Immunotherapy in Oncology by The Lynx Group

BIOLOGICS • VACCINES • BIOTHERAPIES • PRECISION

Immunotherapy in oncology COLORECTAL CANCER

Checkpoint Inhibition: A Promising Immunotherapeutic Approach for Colorectal Cancer..............................Page 8

MELANOMA Pembrolizumab Combination Shows Robust Antitumor Activity.................................................Page 13

SOCIETY FOR IMMUNOTHERAPY OF CANCER Certain Types of T-Cells Show Clinical Benefit in Patients with Glioblastoma.................................................Page 14

STAKEHOLDER PERSPECTIVE

The Coming Government Takeover of Drug Pricing..................................................................Page 20

NATURAL KILLER CELLS

Using Natural Killer Cells in Immunotherapy: What Is Known, and Where to Next...............................Page 22

From the publishers of

The offical publication of

Immunotherapy in oncology BIOLOGICS • VACCINES • BIOTHERAPIES • PRECISION

TABLE OF CONTENTS LETTER TO OUR READERS

A New Year for Immunotherapy

COLORECTAL CANCER

Checkpoint Inhibition: A Promising Immunotherapeutic Approach for Colorectal Cancer

This featured article provides an in-depth review of checkpoint inhibition as it relates to colorectal cancer, and the use of pembrolizumab, nivolumab plus ipilimumab, and durvalumab. MELANOMA

Pembrolizumab Combination Shows Robust Antitumor Activity

This brief overview highlights data from 3 trials demonstrating improved overall response rates in patients with metastatic melanoma taking pembrolizumab (Keytruda) combination therapy. SOCIETY FOR IMMUNOTHERAPY OF CANCER

14 Certain Types of T-Cells Show Clinical Benefit in Patients with Glioblastoma 14 Epacadostat plus Pembrolizumab Shows Promise in Patients with Advanced Cancers 15 Making Headway with Autologous T-Cells in Metastatic Cancer 15 Significance of Mitochondrial Activity in CD8T–NK-Cell Interaction 16 Anti-CD123 plus Anti-CD19 Chimeric Antigen Receptor T-Cells Effective

OUR MISSION Personalized Medicine in Oncology provides the bridge between academic research and practicing clinicians by demonstrating the immediate implications of precision medicine – including advancements in molecular sequencing, targeted therapies, and new diagnostic modalities – to the management of patients with cancer, offering oncologists, oncology nurses, payers, researchers, drug developers, policymakers, and all oncology stakeholders the relevant practical information they need to improve cancer outcomes. This journal translates the new understanding of the biology of cancer into the day-to-day management of the individual patient with cancer, using a patient’s unique genetic makeup to select the best available therapy. OUR VISION Our vision is to transform the current medical model into a new model of personalized care, where decisions and practices are tailored for the individual – beginning with an incremental integration of personalized techniques into the conventional practice paradigm currently in place.

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Immunotherapy in oncology

BIOLOGICS • VACCINES • BIOTHERAPIES • PRECISION

TABLE OF CONTENTS (Continued from page 3) SOCIETY FOR IMMUNOTHERAPY OF CANCER

17 Targeted Treatment Possible in Patients with TNBC Who Overexpress the B7-H4 Receptor 17 CD8+PD-1+ Is Enhanced in Tumor-Reactive, Mutation-Specific Cancer Cells 18 Local Immunotherapy Injection Targets Unresponsive Tumors, Increases Survival STAKEHOLDER PERSPECTIVE

The Coming Government Takeover of Drug Pricing

In this perspective, the author provides a controversial view of drug pricing and purports that ObamaCare provides the tools for a unilateral move against the industry the left loves to demonize. NATURAL KILLER CELLS

Using Natural Killer Cells in Immunotherapy: What Is Known, and Where to Next

In this report, we provide brief highlights of an in-depth review discussing the role of natural killer cell–based therapies targeting cancer, including current data and novel therapies.

Personalized Medicine in Oncology is included in the following indexing and database services: Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCO research databases Personalized Medicine in Oncology, ISSN 2166-0166 (print); ISSN applied for (online) is published 10 times a year by Green Hill Healthcare Communications, LLC, 1249 South River Road, Suite 202A, Cranbury, NJ 08512. Telephone: 732.656.7935. Fax: 732.656.7938. Copyright © 2016 by Green Hill Healthcare Communications, LLC. All rights reserved. Personalized Medicine in Oncology logo is a trademark of Green Hill Healthcare Communications, LLC. No part of this publication may be reproduced or transmitted in any form or by any means now or hereafter known, electronic or mechanical, including photocopy, recording, or any informational storage and retrieval system, without written permission from the publisher. Printed in the United States of America. EDITORIAL CORRESPONDENCE should be addressed to EDITORIAL DIRECTOR, Personalized Medicine in Oncology (PMO), 1249 South River Road, Suite 202A, Cranbury, NJ 08512. YEARLY SUBSCRIPTION RATES: United States and possessions: individuals, $50.00; institutions, $90.00; single issues, $5.00. Orders will be billed at individual rate until proof of status is confirmed. Prices are subject to change without notice. Correspondence regarding permission to reprint all or part of any article published in this journal should be addressed to REPRINT PERMISSIONS DEPARTMENT, Green Hill Healthcare Communications, LLC, 1249 South River Road, Suite 202A, Cranbury, NJ 08512. The ideas and opinions expressed in PMO do not necessarily reflect those of the editorial board, the editorial director, or the publishers. Publication of an advertisement or other product mentioned in PMO should not be construed as an endorsement of the product or the manufacturer’s claims. Readers are encouraged to contact the manufacturer with questions about the features or limitations of the products mentioned. Neither the editorial board nor the publishers assume any responsibility for any injury and/or damage to persons or property arising out of or related to any use of the material contained in this periodical. The reader is advised to check the appropriate medical literature and the product information currently provided by the manufacturer of each drug to be administered to verify the dosage, the method and duration of administration, or contraindications. It is the responsibility of the treating physician or other healthcare professional, relying on independent experience and knowledge of the patient, to determine drug dosages and the best treatment for the patient. Every effort has been made to check generic and trade names, and to verify dosages. The ultimate responsibility, however, lies with the prescribing physician. Please convey any errors to the editorial director.

EDITORIAL BOARD

Melanoma Doug Schwartzentruber, MD Indiana University Simon Cancer Center Indianapolis, Indiana

Kim Margolin, MD University of Washington Fred Hutchinson Cancer Research Center Seattle, Washington

Al B. Benson III, MD, FACP, FASCO Northwestern University Chicago, Illinois

Prostate Cancer Oliver Sartor, MD Tulane University New Orleans, Louisiana

Gene Morse, PharmD University at Buffalo Buffalo, New York

SECTION EDITORS Biomarkers Pranil K. Chandra, DO PathGroup Brentwood, Tennessee

EDITORIAL BOARD Gregory D. Ayers, MS Vanderbilt University School of Medicine Nashville, Tennessee

EDITORS IN CHIEF Sanjiv S. Agarwala, MD St. Luke’s Hospital Bethlehem, Pennsylvania

Darren Sigal, MD Scripps Clinic Medical Group San Diego, California Hematologic Malignancies Gautam Borthakur, MD The University of Texas MD Anderson Cancer Center Houston, Texas Pathology David L. Rimm, MD, PhD Yale Pathology Tissue Services Yale University School of Medicine New Haven, Connecticut Drug Development Igor Puzanov, MD Vanderbilt University Vanderbilt-Ingram Cancer Center Nashville, Tennessee Lung Cancer Vincent A. Miller, MD Foundation Medicine Cambridge, Massachusetts Predictive Modeling Michael Kattan, PhD Case Western Reserve University Cleveland, Ohio Gastrointestinal Cancer Eunice Kwak, MD Massachusetts General Hospital Cancer Center Harvard Medical School Boston, Massachusetts Genetic Counseling Cristi Radford, MS, CGC Moffitt Cancer Center Tampa, Florida

Lyudmila Bazhenova, MD University of California, San Diego San Diego, California Leif Bergsagel, MD Mayo Clinic Scottsdale, Arizona Mark S. Boguski, MD, PhD Harvard Medical School Boston, Massachusetts Gilberto Castro, MD Instituto do Câncer do Estado de São Paulo São Paulo, Brazil Madeleine Duvic, MD The University of Texas MD Anderson Cancer Center Houston, Texas Beth Faiman, PhD, MSN, APRN-BC, AOCN Cleveland Clinic Taussig Cancer Center Cleveland, Ohio Steven D. Gore, MD The Johns Hopkins University School of Medicine Baltimore, Maryland Gregory Kalemkerian, MD University of Michigan Ann Arbor, Michigan Howard L. Kaufman, MD Cancer Institute of New Jersey New Brunswick, New Jersey Katie Kelley, MD UCSF School of Medicine San Francisco, California Minetta Liu, MD Mayo Clinic Cancer Center Rochester, Minnesota

Nikhil C. Munshi, MD Dana-Farber Cancer Institute Boston, Massachusetts Steven O’Day, MD John Wayne Cancer Institute Santa Monica, California Rafael Rosell, MD, PhD Catalan Institute of Oncology Barcelona, Spain Steven T. Rosen, MD, FACP Northwestern University Chicago, Illinois Hope S. Rugo, MD University of California, San Francisco San Francisco, California Lee Schwartzberg, MD The West Clinic Memphis, Tennessee Lillie D. Shockney, RN, BS, MAS Johns Hopkins University Baltimore, Maryland Lawrence N. Shulman, MD Dana-Farber Cancer Institute Boston, Massachusetts Jamie Shutter, MD South Beach Medical Consultants, LLC Miami Beach, Florida David Spigel, MD Sarah Cannon Research Institute Nashville, Tennessee Moshe Talpaz, MD University of Michigan Medical Center Ann Arbor, Michigan Sheila D. Walcoff, JD Goldbug Strategies, LLC Rockville, Maryland Anas Younes, MD The University of Texas MD Anderson Cancer Center Houston, Texas

LETTER TO OUR READERS

A New Year for Immunotherapy Dear Colleague,

hope you had great holidays and a happy New Year! In this first issue of the year, we feature an in-depth review about immune checkpoint inhibition in patients with colorectal cancer. This is a continuation of our series on immunotherapy in specific disease states. In this article, we provide information on microsatellite instability and DNA mismatch, as well as data on combination therapy with the drugs pembrolizumab, nivolumab plus ipilimumab, and durvalumab. “Because the prognosis for patients with recurrent or metastatic colorectal cancer is very poor, alternative strategies such as immunotherapy are needed to improve outcomes for patients Sanjiv S. with advanced disease,” the author concluded (see page 11). Agarwala, MD In addition, we highlight recent data on pembrolizumab combination therapy and data indicating antitumor activity (see Immunotherapy Watch, on page 13). You will read about the latest research in immunotherapy as part of the conference coverage of the 2015 Society for Immu- This is a brand new year for notherapy of Cancer 30th Anniversary Annual Meeting (see immunotherapy. Look to Immunotherapy page 14). In particular, we discuss the clinical benefits associated with T-cells in patients with glioblastoma, the signifi- in Oncology for the latest data on cance of mitochondrial activity in CD8T–natural killer cell advancements in molecular sequencing, interaction, and targeted therapy in patients with renal or targeted therapies, and new diagnostic ovarian cancers who express B7-H4 receptors. In this issue, we also provide an interesting perspective on modalities. the impact of the Affordable Care Act (see “The Coming Government Takeover of Drug Pricing,” on page 20). Let us know your thoughts about this article. We hope you will enjoy this issue, and look forward to your continued feedback. This is a brand new year for immunotherapy. Look to Immunotherapy in Oncology for the latest data on advancements in molecular sequencing, targeted therapies, and new diagnostic modalities. Best regards,

Sanjiv S. Agarwala, MD Editor-in-Chief Immunotherapy in Oncology

COLORECTAL CANCER

Checkpoint Inhibition: A Promising Immunotherapeutic Approach for Colorectal Cancer

ccording to the American Cancer Society, colorectal cancer is the third most common cancer in men and women, and the second leading cause of cancer deaths in the United States.1 An estimated 132,700 new cases of, and 49,700 deaths from, colorectal cancer are expected to occur in 2015. For patients with colorectal cancer, the 5- and 10-year relative survival rates are 65% and 58%, respectively. The 5-year survival rate increases to 90% when coloÂ rectal cancer is detected at a localized stage; however, only 40% of colorectal cancers are diagnosed at this

early stage. The 5-year survival rate drops to 71% if by the time of diagnosis, the cancer has spread regionally and involves nearby organs or lymph nodes. If the disease has metastasized, the 5-year survival rate decreases to 13%. Colorectal cancer is one of the major cancer types with existing US Food and Drug Administration (FDA)-approved targeted therapies (Table 1).2-6 These agents are added to standard first-line chemotherapy for metastatic colon cancer, which can consist of 1 of 2 regimens: fluorouracil (Efudex), leucovorin (Wellcovorin),

Table 1 FDA-Approved Agents for Patients with Metastatic Colorectal Cancer Agent Cetuximab

Bevacizumab

Type mAb

mAb

Target EGFR

VEGF

Year of FDA approval

Indication

2004

First-line therapy for EGFR-expressing metastatic colorectal cancer in combination with irinotecan in patients whose disease is refractory to irinotecan-based chemotherapy

2007

Monotherapy for patients with EGFR-expressing metastatic coloÂ rectal cancer in whom irinotecan- and oxaliplatin-based chemotherapy regimens were not successful

2004

First-line therapy for patients with metastatic colorectal cancer in combination with FOLFIRI therapy

2006

Second-line therapy for metastatic colorectal cancer in combination with fluorouracil-based chemotherapy

Panitumumab

mAb

EGFR

2006

First-line therapy for EGFR-expressing metastatic colorectal carcinoma in patients who are receiving or have already received chemotherapy regimens containing fluoropyrimidine, oxaliplatin, and irinotecan

Ziv-aflibercept

Recombinant fusion protein

VEGF

2012

Second-line therapy for metastatic colorectal cancer in combination with FOLFIRI therapy in patients whose disease is resistant to, or has progressed after, treatment with a regimen containing oxaliplatin

Regorafenib

Multikinase inhibitor

Multiple targets

2012

Second-line therapy for metastatic colorectal cancer in patients who have previously been treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, an anti-VEGF therapy, and, if KRAS wild type, an anti-EGFR therapy

EGFR indicates epidermal growth factor receptor; FDA, US Food and Drug Administration; FOLFIRI, fluorouracil, leucovorin, irinotecan; mAb, monoclonal antibody; VEGF, vascular endothelial growth factor. Sources: References 2-6.

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Table 2 FDA-Approved Anti–PD-1 Antibodies Anti–PD-1 agent

Date of FDA approval

Description

Indication

Pembrolizumab (formerly known as MK-3475, lambrolizumab)

PD-1–blocking mAb

September 2014

Patients with unresectable or metastatic melanoma and disease progression following therapy with ipilimumab, or, in patients who carry a BRAF V600 mutation, after treatment with ipilimumab and a BRAF inhibitor

Nivolumab (formerly known as BMS- 936558)

PD-1–blocking mAb

December 2014

March 2015

Patients with metastatic NSCLC that has progressed during or after platinum-based chemotherapy

FDA indicates US Food and Drug Administration; mAb, monoclonal antibody; NSCLC, non–small-cell lung cancer; PD-1, programmed death receptor-1. Sources: References 8 and 9.

Table 3 Studies of Checkpoint Inhibitors in Patients with Colorectal Cancer Target

Investigational treatment

Study phase

Study population

ClinicalTrials.gov identifier

PD-1

Pembrolizumab monotherapy

Phase 2

Patients with MSI-positive colorectal cancer, MSI-negative colon cancer, and MSI-positive noncolorectal cancers

NCT01876511

PD-1

Pembrolizumab monotherapy

Phase 2

Patients with previously treated, locally advanced, unresectable or metastatic high colorectal cancer

NCT02460198

PD-1

Nivolumab monotherapy; nivolumab plus ipilimumab

Phase 1/2

Patients with recurrent and metastatic MSI-high colon cancer

NCT02060188

PD-L1

Durvalumab

Phase 2

Patients with advanced colorectal cancer

NCT02227667

MSI indicates microsatellite instability; PD-1, programmed death receptor-1; PD-L1, programmed death ligand-1. Sources: References 10-14.

and oxaliplatin (Eloxatin; FOLFOX), or fluorouracil, leucovorin, and irinotecan (Camptosar; FOLFIRI).

Immune Checkpoint Inhibition Of the many approaches currently under investigation to improve antitumor immune responses in patients with colorectal cancer, immune checkpoint inhibition—targeting the programmed death receptor-1 (PD-1) or programmed death ligand-1 (PD-L1)—has proven to be the most effective thus far in a small, phase 2 study.7 Two anti–PD-1 agents (pembrolizu

mab [Keytruda] and nivolumab [Opdivo]) are currently FDA approved for the treatment of patients with cancer (Table 2).8,9 Table 3 lists several clinical studies of checkpoint inhibitor use in patients with colorectal cancer.10-14 Pembrolizumab is being evaluated as monotherapy in patients with colorectal cancer.10,11 Nivolumab is under investigation as monotherapy and in combination with ipilimumab (Yervoy), an antibody that targets cytotoxic T-lymphocyte–associated antigen-4 (CTLA-4), in patients with colorectal cancer.12,15 Durvalumab

COLORECTAL CANCER

(ORR) of 40% (4/10 patients) Figure 2 Immune-Related Progression-Free Survival Rates with Pembrolizumab was observed; no responses (0/18 patients) were observed in the group with MMR-proficient colorectal cancer (Figure 1).22 The immune-related progression-free survival (PFS) rate was 78% (7/9) for patients with MMR-deficient colorectal cancers, and was 11% (2/18) for patients with MMR-proficient colorectal cancers (Figure 2).22 In the cohort with MMR-deficient colorectal cancer, the median PFS and overall survival were not reached, but were 2.2 months and 5.0 months, respectively, in the cohort with MMR-proficient colorectal cancer (hazard ratio for disease progression or death, 0.10 [P <.001], and hazard ratio for death, 0.22 [P = .05]). Similar responses were seen in patients with MMR-deficient noncolorectal MMR indicates mismatch repair; MSI, microsatellite instability. and colorectal cancers (imSource: Reference 22. mune-related ORR, 71% [5/7 patients]; immune-related PFS Nivolumab plus Ipilimumab in Advanced rate, 67% [4/6 patients]). It was Colorectal Cancer revealed, via whole-exome sequencing, that a mean of Studies have demonstrated that combining check1782 somatic mutations existed in MMR-deficient tupoint inhibitors with different mechanisms of action mors versus 73 in MMR-proficient tumors (P = .007). shows promise in patients with advanced cancers.23 High somatic mutation loads were linked to prolonged Nivolumab is under investigation in combination PFS (P = .02). Results of the study by Le and colleagues with ipilimuÂmab, an antibody that targets CTLA-4, in study showed that MMR status predicted the clinical a phase 1/2 study of patients with recurrent and metastatic MSI-high colon cancer.12

Because the prognosis for patients with recurrent or metastatic colorectal cancer is very poor, alternative strategies such as immunotherapy are needed to improve outcomes for patients with advanced disease.

benefit of immune checkpoint blockade with pembrolizumab.22 Based on the encouraging results of this small, early study, a phase 2 study is under way to evaluate the efficacy and safety of pembrolizumab based on MMR status in patients with locally advanced unresectable or metastatic (stage IV) colorectal cancers.11

Durvalumab in Advanced Colorectal Cancer Durvalumab is a human monoclonal antibody that blocks PD-L1 binding to PD-1 and CD-80 with high affinity and selectivity.13,14 A phase 2 study of this drug is currently under way in patients with advanced coÂ lorectal cancer. Conclusion Because the prognosis for patients with recurrent or metastatic colorectal cancer is very poor, alternative strategies such as immunotherapy are needed to improve outcomes for patients with advanced disease. Although results from a small study of pembrolizumab indicate that MMR status predicted clinical benefit, additional studies of other agents may uncover addi-

COLORECTAL CANCER

tional subsets of patients who may benefit from immunotherapy. As researchers gain understanding about the heterogeneity of colorectal tumors, patient stratification based on molecular subtypes holds promise to improve the clinical outcomes. u

References

1. American Cancer Society. Cancer facts & figures, 2015. www.cancer.org/acs/ groups/content/@editorial/documents/document/acspc-044552.pdf. Accessed December 17, 2015. 2. National Cancer Institute. FDA approval for cetuximab. www.cancer.gov/ about-cancer/treatment/drugs/fda-cetuximab. Updated July 2, 2013. Accessed December 21, 2015. 3. National Cancer Institute. FDA approval for bevacizumab. www.cancer.gov/ about-cancer/treatment/drugs/fda-bevacizumab. Updated December 4, 2014. Accessed December 21, 2015. 4. National Cancer Institute. FDA approval for panitumumab. www.cancer.gov/ about-cancer/treatment/drugs/fda-panitumumab. Updated July 3, 2013. Accessed December 21, 2015. 5. National Cancer Institute. FDA approval for ziv-aflibercept. www.cancer.gov/ about-cancer/treatment/drugs/fda-ziv-aflibercept. Updated July 3, 2013. Accessed December 21, 2015. 6. National Cancer Institute. FDA approval for regorafenib. www.cancer.gov/ about-cancer/treatment/drugs/fda-regorafenib. Updated July 3, 2013. Accessed December 21, 2015. 7. Jacobs J, Smits E, Lardon F, et al. Immune checkpoint modulation in colorectal cancer: whatâ&#x20AC;&#x2122;s new and what to expect. J Immunol Res. 2015;2015:158038. 8. Keytruda [package insert]. Whitehouse Station, NJ: Merck & Co, Inc; 2015. 9. Opdivo [package insert]. Princeton, NJ: Bristol-Myers Squibb Company; 2015. 10. ClinicalTrials.gov. Phase 2 study of MK-3475 in patients with microsatellite unstable (MSI) tumors. https://clinicaltrials.gov/ct2/show/NCT01876511?term=NCT 01876511&rank=1. Updated June 9, 2015. Accessed December 21, 2015. 11. ClinicalTrials.gov. Study of pembrolizumab (MK-3475) as monotherapy in par-

ticipants with previously-treated locally advanced unresectable or metastatic colorectal cancer (MK-3475-164/KEYNOTE-164). https://clinicaltrials.gov/ct2/show/ NCT02460198?term=NCT02460198&rank=1. Updated November 3, 2015. Accessed December 21, 2015. 12. ClinicalTrials.gov. A study of nivolumab and nivolumab plus ipilimumab in recurrent and metastatic colon cancer (CheckMate 142). https://clinicaltrials.gov/ct2/ show/NCT02060188?term=NCT02060188&rank=1. Updated December 8, 2015. Accessed December 21, 2015. 13. AstraZeneca. MedImmune and Mirati Therapeutics partner on immuno-oncology combination in lung cancer. www.astrazeneca.com/our-company/media-centre/pressreleases/2015/medimmune-mirati-therapeutics-immuno-oncology-combinationlung-cancer-05082015.html. Published August 5, 2015. Accessed December 21, 2015. 14. ClinicalTrials.gov. Evaluate the efficacy of MEDI4736 in immunological subsets of advanced colorectal cancer. https://clinicaltrials.gov/ct2/show/NCT0222 7667?term=NCT02227667&rank=1. Updated October 28, 2015. Accessed December 21, 2015. 15. US Food and Drug Administration. FDA approves Yervoy to reduce the risk of melanoma returning after surgery. www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm469944.htm. Updated October 29, 2015. Accessed December 21, 2015. 16. Heinimann K. Toward a molecular classification of colorectal cancer: the role of microsatellite instability status. Front Oncol. 2013;3:272. 17. Poulogiannis G, Frayling IM, Arends MJ. DNA mismatch repair deficiency in sporadic colorectal cancer and Lynch syndrome. Histopathology. 2010;56:167-179. 18. Kloor M, Staffa L, Ahadova A, von Knebel Doeberitz M. Clinical significance of microsatellite instability in colorectal cancer. Langenbecks Arch Surg. 2014;399:2331. 19. Topalian SL, Hodi FS, Brahmer JR, et al. Safety, activity, and immune correlates of anti-PD-1 antibody in cancer. N Engl J Med. 2012;366:2443-2454. 20. Brahmer JR, Tykodi SS, Chow LQ, et al. Safety and activity of anti-PD-L1 antibody in patients with advanced cancer. N Engl J Med. 2012;366:2455-2465. 21. Droeser RA, Hirt C, Viehl CT, et al. Clinical impact of programmed cell death ligand 1 expression in colorectal cancer. Eur J Cancer. 2013;49:2233-2242. 22. Le DT, Uram JN, Wang H, et al. PD-1 blockade in tumors with mismatch-repair deficiency. N Engl J Med. 2015;372:2509-2520. 23. Wolchok JD, Kluger H, Callahan MK, et al. Nivolumab plus ipilimumab in advanced melanoma. N Engl J Med. 2013;369:122-133.

MELANOMA

Pembrolizumab Combination Shows Robust Antitumor Activity Christine Anderson

n 3 phase 1 and 2 studies, improved overall response rates (ORRs) were shown in patients with metastatic melanoma taking pembrolizumab (Keytruda) in combination with 3 other immunotherapies, including epa cadostat, talimogene laherparepvec (Imlygic), and ipi limumab (Yervoy). All 3 studies demonstrated significant antitumor activity. In addition, long-term follow-up data in a phase 3 study indicated improved ORR and progression-free survival (PFS) in pembrolizumab compared with ipilimumab. The KEYNOTE-037 trial is an ongoing, phase 1/2 study evaluating pembrolizumab (2 mg/kg or 200 mg every 3 weeks) plus epacadostat (25, 50, 100, or 300 mg twice daily) in patients with advanced cancers. Early data showed that in 19 patients, this combination therapy demonstrated an ORR of 53%; there were 3 complete responses (CRs) and 7 partial responses (PRs). Grade 3 treatment-related adverse events included rash (8%), arthralgia (2%), aspartate aminotransferase (AST) increase (2%), mucosal inflammation (2%), and nervous system disorder (2%). No grade 4 adverse events or deaths were observed. Another ongoing phase 1b study, MASTERKEY-265, is assessing the safety, efficacy, and tolerability of pembrolizumab plus talimogene laherparepvec—a herpes simplex virus-1–based oncolytic immunotherapy—in patients with previously untreated and unresected advanced melanoma. In the 16 patients evaluated, pembrolizumab (200 mg every 2 weeks) plus talimogene laherparepvec (up to 4 mL of 106 PFU/mL, followed by 108 PFU/mL every 2 weeks) resulted in an unverified ORR of 56.3% (95% confidence interval [CI], 19.870.1), with 2 CRs and 7 PRs. The most common adverse events of any grade were fatigue (52%), pyrexia (48%), chills (43%), rash (38%), headache (33%), and nausea (33%); grade 3 adverse events included headache (5%) and diarrhea (5%). The third study, KEYNOTE-029, is an ongoing phase 1/2 study of patients with advanced melanoma receiving pembrolizumab plus low-dose ipilimumab. Researchers are investigating whether lower doses of ipilimumab improve patients’ tolerance of this combination. Of the 72 evaluable patients, pembrolizumab

(2 mg/kg every 3 weeks) plus low-dose ipilimumab (1 mg/kg every 3 weeks for 4 doses) exhibited an ORR of 56% (95% CI, 43-67), with 3 CRs and 37 PRs. Grades 3 and 4 treatment-related adverse events were observed in 36% of patients, including lipase increase (8%), amylase increase (6%), alanine transferase increase (6%), AST increase (4%), rash (3%), and diarrhea (1%). Grades 3 and 4 immune-mediated adverse events included thyroiditis, hypophysitis, type 1 diabetes mellitus, pneumonitis, colitis, hepatitis, pancreatitis, severe skin reactions, and renal events. Phase 3 trials are planned for each of these studies based on these results. In addition, recent data from KEYNOTE-006, an open-label, randomized, phase 3 study of patients with unresectable stage 3 or 4 advanced melanoma, showed that patients receiving pembrolizumab as a single agent experienced improved ORR and PFS compared with ipilimumab in ipilimumab-naïve patients. These findings are based on 6 additional months of follow-up. PFS rates for pembrolizumab at 12 months were 37.7% in the cohort receiving the drug every 2 weeks, and 36.3% in the cohort receiving pembrolizumab every 3 weeks, compared with 17.2% in patients receiving ipilimumab (hazard ratio [HR], 0.60 [95% CI, 0.49-0.74] and HR, 0.59 [95% CI, 0.48-0.73], respectively). The ORR was 36.2% and 36.1% in patients receiving pembrolizumab every 2 weeks or every 3 weeks, respectively (95% CI, 30.6-42.1 and 95% CI, 30.4-42.1, respectively), compared with 12.9% for ipilimumab (95% CI, 9.2-17.5). New patient-reported, health-related, quality-of-life outcomes showed that physical, emotional, cognitive, and social functioning were better maintained in patients receiving pembrolizumab than in patients receiving ipilimumab. In addition, baseline fatigue, pain, dyspnea, appetite loss, and diarrhea worsened to a lesser degree in patients receiving pembrolizumab than in patients receiving ipilimumab. u Merck & Co. Inc. Merck announces initial results for Keytruda® (pembrolizumab) with novel immunotherapy combinations from 3 investigational studies presented at the Society for Melanoma Research International Congress. www.mercknewsroom.com/news-release/pre scription-medicine-news/merck-announces-initial-re sults-keytruda-pembrolizumab-novel. Published November 21, 2015. Accessed December 2, 2015.

SOCIETY FOR IMMUNOTHERAPY OF CANCER

Certain Types of T-Cells Show Clinical Benefit in Patients with Glioblastoma And other news from the 2015 Society for Immunotherapy of Cancer Christine Erickson, Conference Correspondent

lthough the current standards of care cannot cure glioblastoma (GBM), an adoptive T-cell transfer may help improve outcomes in patients with GBM. At the 2015 Society for Immunotherapy of Cancer 30th Anniversary Annual Meeting, researchers reported their findings from a phase 1 clinical trial, NCT01109095. They observed patients with progressive GBM receiving autologous cytomegalovirus (CMV).pp65 T-cells that were grafted with a second-generation HER2 chimeric antigen receptor (CAR) with a CD28.zeta signaling domain.

Systemically administered HER2 CAR CMV bispecific T-cells are safe, and that approximately 38% of patients experienced a durable clinical benefit. The trial comprised 17 CMV-seropositive patients with radiologically progressive HER2-positive GBM. The median age was 49 years (range, 11-71 years), and included 6 children and 11 adults. The children who were enrolled had significantly larger tumor volumes at the time of infusion. With a peripheral blood draw (90 mL maximum), a cell product was successfully generated for all patients. The researchers found that a median of 67% (range, 46%-82%) of T-cells expressed the HER2 CAR, and demonstrated a median of 985.5 (range, 390-1292) CMV.pp65 reactivity in an interferon-γ Elispot assay (spot-forming cells/105 T cells). Infusions of 1×106/m2 to 1×108/m2 were well tolerated, and there were no severe adverse events or cytokine release syndrome. HER2 CMV T-cells were identified in the peripheral blood for ≤2 weeks postinfusion, according to the real-time polymerase chain reaction of a CAR-specific amplicon. Of the 16 evaluable patients, 8 patients showed progressive disease and 8 patients had objective responses.

One patient experienced a partial response with an approximately 62% reduction in tumor volume lasting 8 months. A total of 7 patients experienced stable disease for >6 weeks (of these, 5 were durable for >10 weeks), and 3 patients currently have a follow-up of 24 to >30 months following T-cell infusion. The median survival was 11.6 months from the time of infusion, and 24.8 months from the time of diagnosis. The median survival for the adults in the trial was 30 months from the time of diagnosis. The researchers concluded that systemically administered HER2 CAR CMV bispecific T-cells are safe, and that approximately 38% of patients experienced a durable clinical benefit.

Epacadostat plus Pembrolizumab Shows Promise in Patients with Advanced Cancers Indoleamine 2,3-dioxygenase 1 (IDO1) is a tryptophan-catabolizing enzyme that induces immune tolerance by suppressing T-cell responses, and is found in many cancer types. Epacadostat is a potent, selective oral inhibitor of IDO1. A dose-escalation study of patients with advanced melanoma receiving epacadostat plus ipilimumab showed a favorable overall response rate (ORR), disease control rate (DCR), and progression-free survival in participants who were immunotherapy-naïve (Gibney G, et al. Abstract presented at European Cancer Congress; September 25-29, 2015;Vienna, Austria). Researchers presented their own ongoing dose-escalation and dose-expansion study at the 2015 Society for Immunotherapy of Cancer 30th Anniversary Annual Meeting. This study analyzes epacadostat plus pembrolizumab in patients with stage IIIB, stage IV, or recurrent non–small-cell lung cancer (NSCLC), melanoma, transitional cell carcinoma (TCC), renal-cell carcinoma (RCC), endometrial adenocarcinoma (EA), or squamous-cell carcinoma of the head and neck (SCCHN). Patients were excluded from the study if they were previously treated with anti–PD-1 or anti– CTLA-4 therapies. Enrollment is complete in the epacadostat 25-mg twice-daily, 50-mg twice-daily, and

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100-mg twice-daily groups with pembrolizumab 2 mg/ kg intravenously every 3 weeks. Expansion groups are currently being enrolled for epacadostat 50 mg twice daily, 100 mg twice daily, and 300 mg twice daily with pembrolizumab 200 mg. A total of 54 patients were enrolled in the study as of August 21, 2015. The researchers included safety data on 28 patients (melanoma, n = 11; RCC, n = 5; NSCLC, n = 5; TCC, n = 3; EA, n = 2; and SCCHN, n = 2); 19 patients are evaluable for efficacy as of July 13, 2015. A dose-limiting, grade 3 rash was observed in 1 of 8 patients receiving epacadostat 50 mg twice daily and pembrolizumab 2 mg/kg. No dose-limiting toxicities were

Epacadostat plus pembrolizumab was well tolerated, and the efficacy data suggest encouraging clinical activity. observed in patients receiving epacadostat 100 mg and pembrolizumab 2 mg/kg. The most common (≥20%) adverse events were fatigue, diarrhea, rash, arthralgia, and nausea; the majority were grade 1 or 2. Immune-related adverse events grade ≥3 were mucosal inflammation and rash. Tumor burden reductions were observed in 15 of the 19 evaluable patients. The responses are ongoing, and were observed in all tumor types. In 7 evaluable patients with melanoma, the ORR was 57%, and the DCR was 86%, including 2 complete responses. In 5 evaluable patients with RCC, the ORR was 40% and the DCR was 80%. Based on a pharmacokinetic–pharmacodynamic model for epacadostat, nearly all patients’ Cavg exceeded the IC50, which is the range of active drug exposure seen in preclinical models. The researchers concluded that epacadostat plus pembrolizumab was well-tolerated, and that the efficacy data suggest encouraging clinical activity. They are evaluating the correlations between biomarker expression and response, and will present the updated data.

Making Headway with Autologous T-Cells in Metastatic Cancer In patients with metastatic melanoma who have received an adoptive cell transfer of patient-derived tumor-infiltrating lymphocytes (TILs), durable complete response rates of 20% have been observed. To further explore these findings, researchers conducted an analysis of TIL that was administered to a pa-

tient with metastatic melanoma who had a complete response for >3 years. Results of the analysis, which were presented at the 2015 Society for Immunotherapy of Cancer 30th Anniversary Annual Meeting, showed that the autologous TIL recognized 10 specific somatically mutated gene products. The investigators identified >4000 nonsynonymous somatic mutation variants by employing whole exome and ribonucleic acid sequencing, with a bioinformatic analysis of the patient’s matched tumor and normal gDNA. A total of 745 somatically mutated genes were screened with tandem minigene constructs that expressed transcripts expressed in autologous tumor cells with expression levels >0.1% of the β-actin levels. Following this, the tandem minigenes were transfected into autologous B-cells, and analyzed for their capacity to stimulate the T-cells that were administered. The results of this analysis showed that the autologous TIL recognized 10 somatically mutated gene products, and each of these gene products was recognized in the context of 3 separate human leukocyte antigen class I restriction elements that were expressed by the patient’s tumor. A detailed T-cell clonal analysis showed that 9 of 20 major clones that were present in the infused TIL encompassed >25% of the total infused cells. These clones also recognized mutated antigens. The results of this analysis helped further support the researchers’ efforts toward identifying mutation-reactive T cells for treating patients with metastatic cancer.

Significance of Mitochondrial Activity in CD8T–NKCell Interaction Patients with an increasingly diverse collection of major histocompatibility complex (MHC) class I molecules are likely to have more responsive natural killer (NK)-cells. In addition, NK-cells with a larger number of inhibitory receptors that recognize surrounding MHC class I molecules respond to stimuli better than NK-cells that have less recognition of the surrounding MHC. At the 2015 Society for Immunotherapy of Cancer 30th Anniversary Annual Meeting, investigators shared their observations of the mechanisms of local tumor antigen-specific T-cell-NK-cell collaboration. This collaboration appeared to be essential for eliminating tumor cells, including antigen-deficient tumor escape variants that appear before metastasis occurs. The investigators observed a mouse model of mastocytoma expressing a self-tumor–antigen P1A. The effector CD8T-cells assisted dormant NK-cells by triggering their antitumor effector function. After an adoptive transfer of P1A-specific T-cells in RAG-/- and RAG-/γc-/- in mice, bioluminescence imaging of mastocytoma tumors showed that NK-cell antitumor activity requires

SOCIETY FOR IMMUNOTHERAPY OF CANCER

cytolytic T-cells, where the T-cells can function without NK-cells. Phorbol myristate acetate and ionomycin-stimulated CD8T have cells formed multiple links with naïve NK lymphocytes in 2D and 3D coculture systems. Data have shown that NK-cells that interact with activated CD8T cells display an upregulation of CD25 and CD69 expression that is mediated by intercellular contacts, as well as the activation of NKG2D receptors and Stat2, Stat6, Jak1, Jak3, Tyk2, and PTEN signaling molecules, with a decrease in the phosphorylation of Stat1, PKB/Akt, SAPK/JNK, and p38.

These findings underscore the significance of mitochondrial activity in the renovation of activation signaling and memory distinction of CD8T–NK-cell interaction. However, the investigators noted that interacting NK-cells downregulate the CD25 molecule expression on CD8T-cells, and encourage the distinction of central-memory CD44+CD62L+T-cells. CD8T-cells demonstrate an elevation in the phosphorylation of Stat1, and a downregulation of Stat5 with stimulated PKB/Akt, Lck, mTOR, and p42/p44. Changes in the phosphorylation status of multiple signaling proteins during CD8T–NK-cell interaction imply a cellular remodeling, where NK-cells polarize activated CD8T-cells toward a central-memory phenotype, and activated CD8T lymphocytes prompt naïve NK-cells toward an effector or regulatory phenotype. In addition, significant cytosolic and mitochondrial Ca2+ changes, mitochondrial reactive oxygen species production, mitochondrial membrane potential, mitochondrial permeability transition pore, and synthesis of nitric oxide and nonprotein thiols—mostly reduced glutathione—were observed in a mutual CD8T–NK-cell interaction. The investigators’ findings underscore the significance of mitochondrial activity in the renovation of activation signaling and memory distinction of CD8T– NK-cell interaction. This has the potential to enhance strategies for cancer immunotherapy.

Anti-CD123 Plus Anti-CD19 Chimeric Antigen Receptor T-Cells Effective Anti-Cluster of Differentiation 19(CD19) chimeric antigen receptor T-cells (CART19) and bispecific anti-CD19/CD3 antibodies (blinatumomab) are now generating complete responses in patients with relapsing/

refractory B-cell acute lymphoblastic leukemia (ALL). However, some of these patients still relapse as a result of a loss of detectable CD19 (Maude SL, et al. N Engl J Med. 2014;371:1507-1517). The interleukin-3 receptor alpha (CD123) was shown to be expressed in several hematologic neoplasms, including acute myeloid leukemia, and, recently, B-cell acute ALL. Marco Ruella, MD, Center for Cellular Immunotherapies, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and colleagues evaluated the impact of targeting CD19 and CD123 with chimeric antigen receptor T-cells on treatment and prevention of CD19-negative relapses in patients who have previously received CD19-directed therapies. The authors analyzed CD123 expression with flow cytometry in 36 relapsing/refractory B-cell ALL samples. They found that CD123 was highly expressed (81.75%, range: 5.10-99.60); therefore, CD123 was shown to be a promising option for targeted therapy in patients with B-cell acute ALL. The authors also found that CD123 was expressed in putative leukemia stem cells, identified as CD34-positive and CD38-negative. In addition, an expression of CD123 was detected in all (N = 6) CD19-negative B-cell acute ALL blasts that were analyzed after patients relapsed with CART19 treatment. Thus, Dr Ruella and colleagues produced CART123, which was costimulated with 4-1-BB using a lentiviral vector. They then evaluated the antileukemia efficacy of CART123 in vitro and in vivo against primary B-cell acute ALL blasts, and the NALM-6 cell line. CART123 showed intense antileukemia activity, defined by a specific CD107a degranulation, cytokine production, cytotoxicity, and proliferation. However, these results were not statistically different from that of CART19. To test the role of CART123 in targeting CD19-negative relapses, the authors developed a new in vivo model, engrafting immunodeficient NOD/SCID/ gamma mice with blasts from a patient with CD19-negative disease who relapsed after treatment with CART19. At day 14, the mice were randomized to receive control T cells, CART19, or CART123 in combination with CART19. CART19 and control T-cell–treated mice showed no antitumor activity; however, CART123 plus CART19 resulted in long-term survival, and complete elimination of the disease. “Here we demonstrate that CD123 is expressed in CD19-negative [B-cell acute ALL] relapses occurring after CD19-directed therapies,” the study authors explained. “Combining CART123 cells with CART19 cells is an effective therapy for the treatment and prevention of antigen-loss relapses in [B-cell acute ALL] murine xenografts.”

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Targeted Treatment Possible in Patients with TNBC Who Overexpress the B7-H4 Receptor B7-H4, a coregulatory receptor that is thought to negatively regulate T-cell function, has been associated with poor prognosis in patients with renal-cell and ovarian cancers. Donald R. Shaffer, PhD, Jounce Therapeutics, Cambridge, MA, and colleagues analyzed gene expression data from the Cancer Genome Atlas, and found that of all the tumors that were analyzed, patients with triple-negative breast cancer (TNBC) had the greatest absolute B7-H4 messenger ribonucleic acid level. Recent clinical trials of anti–programmed cell death1 (PD-1) or programmed death-ligand 1 (PD-L1) therapies have shown promising activity in patients with TNBC. As a result, the study authors investigated archived samples from a cohort of 96 patients with TNBC, which were collected at Yale University, New Haven, CT. Based on these data, checkpoint molecule expression (PD-1, PD-L1, and B7-H4) and immune-cell infiltration expression (CD8, Fox P3) were explored in this patient sample.

The unique expression pattern of B7-H4 in patients with TNBC suggests that there is an opportunity to incorporate targeted treatment approaches with possible immunomodulatory activity. “We developed a specific and sensitive immunohistochemistry (IHC) assay for evaluating B7-H4 protein, and used an immunofluorescence-based multiplex IHC for assessing combinations of checkpoint molecules in the TNBC samples,” Shaffer and colleagues described. They also noted that they were able to detect expression of B7-H4 in the majority of tumors, but expression of PD-L1 was limited to a subset of patients with TNBC; approximately 20% of patients had >5% of PD-L1–positive cells. An analysis of multiplex IHC and flow cytometry showed that the majority of B7-H4 expression was restricted to the tumor epithelial cells, whereas the CD45+ immune cells were shown to be negative for B7-H4 expression. Of note, a majority of the tumors that highly expressed B7-H4 were negative, or showed little PD-L1 staining. In addition, the cells that were B7-H4–positive were negative for PD-L1 staining, which suggests that B7-H4 and PD-L1 checkpoint pro-

teins may act in a mutually exclusive fashion. B7-H4 expression was not associated with overall survival, disease stage, nodal status, or other clinical characteristics; however, PD-L1, PD-1, and CD8 expression all presented a significant survival advantage for patients with TNBC, underscoring the importance of the immune response in this patient population. When the authors further investigated these data, they were unable to find a definitive immunosuppressive role of B7-H4, which is contrary to the results of previously published literature. However, overexpression of B7-H4 in a CT-26 syngeneic in vivo model accelerated tumor growth. The unique expression pattern of B7-H4 in patients with TNBC suggests that there is an opportunity to incorporate targeted treatment approaches with possible immunomodulatory activity. More research is needed on this topic to further explain the immunologic mechanisms of B7-H4. However, the study authors suggest that the unique expression pattern of B7-H4 means that it could be an appealing option for the targeted treatment of patients with TNBC.

CD8+PD-1+ Is Enhanced in Tumor-Reactive, MutationSpecific Cancer Cells T-cells that target unique somatic mutations seem to play a significant role in antitumor responses that occur after T-cell transfer. Furthermore, the isolation of mutation-specific lymphocytes and T-cell receptors has become a hindrance in the development of more effective immunotherapies. Identifying tumor-reactive and mutation-specific cells in patients with cancer has been mainly limited to tumor-infiltrating lymphocytes, but mutation-specific cells are thought to be considerably less prevalent in peripheral blood, which is a more accessible and ample source of T-cells. Alena Gros, PhD, National Cancer Institute, National Institutes of Health, Bethesda, MD, and colleagues previously found that anti–programmed cell death-1 (PD-1) expression identifies the patient-specific catalog of tumor-reactive cells that infiltrate melanoma tumors. Based on these findings, the authors analyzed the utility of PD-1 expression with peripheral blood lymphocytes to detect tumor- and neoantigen-specific lymphocytes, and presented their analysis. The authors separated peripheral blood CD8+ lymphocytes based on PD-1 expression into CD8+PD-1–, CD8+PD-1+, and CD8+PD-1hi cells, and expanded them in vitro for 15 days. They subsequently screened circulating T-cell subsets to acknowledge mutated antigens identified by whole exome sequencing. A high throughput and personalized approach that allows the expression of all potential tumor neoantigens in the au-

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tologous antigen-presenting cells was used. The recognition of shared melanoma differentiation antigens, and cancer germline antigens was also evaluated. “PD-1+ lymphocytes represented a small percentage of all the circulating CD8+ cells in patients with metastatic melanoma,” Gros and colleagues explained. “We found that selection of CD8+PD-1+ lymphocytes circulating in peripheral blood, but not the CD8+ or CD8+PD-1- cells, led to direct enrichment of tumor-reactive cells from peripheral blood in all 4 patients studied.”

These results show that peripheral blood CD8+PD-1+ in patients with cancer is enhanced in naturally occurring, tumorreactive and mutation-specific cells, and provides a new approach for developing personalized T-cell–based therapies to treat patients with cancer. In 3 of 4 patients with melanoma, peripheral blood CD8+PD-1+ and PD-1hi cells included mutation-specific lymphocytes that targeted 3, 3, and 1 unique patient-specific neoantigens, respectively. Circulating CD8+PD-1+ and PD-1hi lymphocytes in the 4 patients with melanoma were also enriched in T-cells that targeted ≥1 cancer germline antigens, including NYESO-I, MAGE-A3, and SSX2. Mutation- and cancer germline-specific lymphocytes were not detected in the peripheral blood CD8+, or in the CD8+PD-1– group. These results show that peripheral blood CD8+PD-1+ in patients with cancer is enhanced in naturally occurring, tumor-reactive and mutation-specific cells, and provides a new approach for developing personalized T-cell–based therapies to treat patients with cancer.

Local Immunotherapy Injection Targets Unresponsive Tumors, Increases Survival With the growing anticipation for new approaches to immunotherapy, viral cancer therapy has shifted from mainly providing oncolysis, to immunotherapy. “Adenoviruses have a unique ability to prime and boost immune responses,” Sari Pesonen, Oncos Therapeutics, Helsinki, Finland, and colleagues noted. “Granulocyte-macrophage colony-stimulating factor coding adenovirus ONCOS-102 causes immunogenic cancer cell death whereupon tumor antigens are presented into the immunogenic environment.”

Previously, ONCOS-102 has been shown to initiate CD8+ T-cell responses against tumor-derived antigens in patients with chemotherapy-refractory cancer. To further explore the impact of local immunotherapy with ONCOS-102, the study authors conducted a phase 1 study, and presented their findings at the 2015 Society for Immunotherapy of Cancer 30th Anniversary Annual Meeting. The study included 12 patients with cancer who received recurring ONCOS-102 intratumoral injections. Researchers collected biopsies at baseline, 1 month, and 2 months after the initial treatment. Using immunohistochemistry (IHC), the biopsy results were analyzed for the presence of immune cells. The expression levels for innate immune (CD68, CD163, CD11c), T- (CD3, CD4, CD8), and B- (CD19) cells were analyzed in tumorous regions with an image analysis algorithm based on color deconvolution and division of the IHC-stained cells. When the authors conducted an exploratory analysis, they found a correlation between the total expression levels of immune-cell markers in the tumors. The correlation between overall survival (OS) and absolute expression levels of different immune-cell markers in tumors was assessed with Spearman’s rank correlation analysis. The absolute expression level of macrophage marker CD68 negatively correlated with OS (P = .04) at baseline. This suggests that tumor-associated macrophages (TAMs) were tumorigenic in untreated tumors. No correlation was observed between other immune-cell markers and OS at baseline. Of the 12 total patients included, 11 showed an increase in tumor-infiltrating innate and adaptive immune cells posttreatment. The most evident increase was observed in CD8+ cells. Posttreatment samples showed a positive correlation between CD68+ cell expression levels and OS (P = .01) compared with baseline. This suggested that the CD68+ macrophages that were drawn to tumors after ONCOS-102 injection displayed a different utility than pretreatment TAMs. In addition, the total expression levels of T-cell markers CD3 (P = .006), CD4 (P = .004), and CD8 (P =.007) all positively correlated with OS in posttreatment biopsies. Ultimately, the ONCOS-102 injection generated infiltration of CD68+ macrophages and T-cells. This was associated with increased OS, whereas pretreatment with CD68+ TAMs was associated with decreased OS. These results suggest that local immunotherapy with ONCOS-102 can activate immunologically unresponsive tumors, and reduce local immune suppression in patients with metastatic tumors. u

STAKEHOLDER PERSPECTIVE

The Coming Government Takeover of Drug Pricing ObamaCare provides the tools for a unilateral move against the industry the left loves to demonize. Scott Gottlieb

illary Clinton has plenty of allies as she demonizes drug-company profits and pushes for federal control over how drugs are priced. There’s a drug-pricing task force led by the White House and a similar Democrat-led effort in Congress. Many of the pharma industry’s proponents in Washington and on Wall Street dismiss this as political noise, arguing that new restrictions impeding investment and innovation are unlikely to get through a Republican Congress. But the Affordable Care Act reordered the legal framework to let a president impose price restrictions unilaterally through the Independent Payment Advisory Board and the Center for Medicare and Medicaid Innovation. These executive-branch bodies were crafted to control what procedures doctors perform, but there is reason to believe they can also control drug prices.

These executive-branch bodies were crafted to control what procedures doctors perform, but there is reason to believe they can also control drug prices. The Independent Payment Advisory Board was designed to take decisions about how to reduce Medicare’s spending out of any public debate. The board’s appointed academicians have no statutory obligation to engage in the public notice and comment that is customary in regulation. IPAB decisions are exempt from judicial review and appeal, and they take effect without Congress. The board is barred by law from making big changes to the structure of Medicare. As a result, its focus probably will turn to implementing price controls and ways to give Scott Gottlieb is a physician and resident fellow at the American Enterprise Institute. He consults with and invests healthcare companies.

Medicare the power to control the use of new technology. The Center for Medicare and Medicaid Innovation is similarly able to create new payment rules—even if they conflict with existing law—to target medical technology and procedures that seem to be spending outliers, costing Medicare more than some ill-defined norm. Under the ObamaCare statute, CMMI can flout any existing Medicare rule by designing “pilot” programs that needn’t be small in scale. Regarding drug prices, IPAB and CMMI are likely to engage in so-called reference pricing that is the backbone of European-style price controls. Under this construct, the agencies will allow the Medicare program to lump together drugs and other treatments that the agencies’ bureaucrats feel are similar enough that they can be used in place of one another—even if a newer but also more expensive treatment might offer benefits over older alternatives. Think of a new cancer drug that obviates a far less-tolerable form of chemotherapy. Only Medicare says the new drug should be priced the same as old, generic chemo because the Food and Drug Administration says that the two remedies have a similar treatment effect. Medicare has long wanted the authority to say that it would only pay for the “least costly alternative” treatment within a given set of therapeutic options. The powers of the Independent Payment Advisory Board are only triggered when Medicare’s rate of spending growth is projected to rise faster than a peg that’s tied to inflation. Medicare’s projections show that this threshold will be triggered in 2017, and maybe sooner. So as a new president takes over, he or she will inherit broad authority to unilaterally rewrite Medicare’s payment rules. The effect on the availability of new treatments could be cataclysmic. Drug discovery is a high-risk, high-cost endeavor. Mounting regulation already has stretched the average time to develop a drug to 128 months between synthesizing a pill and winning its approval. Only about 10% of the drugs that go through Phase I clinical trials

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reach the market. Average out-of-pocket spending is $1.4 billion to develop a new medicine, with an additional $470 million in direct, post-market research costs after a drug is approved.

Constructs like the Independent Payment Advisory Board are unpopular among liberals and conservatives because they target hospitals and providers as well as drugs. Much of this money is spent meeting regulatory demands. In 2002 there were 494,000 data points collected to satisfy regulatory requirements in a typical, late-stage Phase III clinical trial. By 2012 researchers at the Tufts Center for the Study of Drug Development found that figure had grown to 929,000. Government rules like the existing price controls in Medicaid prevent drug developers from experimenting

with new ways to price their products according to the value they’re delivering, like charging different prices based on the indication that a medicine is being used for. Or tying a drug’s price to how well a patient is responding to the treatment. These are far better alternatives to price controls, but, ironically, the government’s price interventions prevent these approaches. Constructs like the Independent Payment Advisory Board are unpopular among liberals and conservatives because they target hospitals and providers as well as drugs. Yet conservatives in Congress have passed on chances to cut away IPAB and the Center for Medicare and Medicaid Innovation. They fear that excising the law’s gangrenous decay makes the whole carcass harder to bury. But leaving these appendages in place weakens their hand. ObamaCare was designed to infect the normal political balance over health policy. The drug kerfuffle will demonstrate how much control Congress has already ceded. u Reprinted by permission of The Wall Street Journal. Copyright © 2015 Dow Jones & Company, Inc. All Rights Reserved Worldwide. License number 3773740113451.

NATURAL KILLER CELLS

Using Natural Killer Cells in Immunotherapy: What Is Known, and Where to Next E. K. Charles, Medical Writer

n their review article, Carin I. M. Dahlberg, PhD, from the Cell Therapies Institute, Nova Southeastern University, Fort Lauderdale, FL, and the Cell and Gene Therapy Group, Center for Hematology and Regenerative Medicine, Karolinska University Hospital Huddinge, NOVUM, Stockholm, Sweden, and colleagues evaluated natural killer (NK)-cell–based therapies targeting cancer. In particular, they discussed current data on the use of NK-cells, as well as novel therapies, including genetic modification and complementary therapies seeking to improve the clinical outcomes of NK-cell–based immunotherapies.

“In the near future, different NK-cell–based products will reach multicenter clinical trial stage, and we will start to see efficacy data.” —Carin I. M. Dahlberg, PhD, and colleagues “Even though NK-cell–based therapies represent one of the most promising strategies to combat cancer, to our knowledge, no clinical trial has clearly demonstrated a significant benefit in patients with malignancies,” the study authors explained. “Nevertheless, there is a lot of promise in early clinical and preclinical data that cannot be omitted. In the near future, different NK-cell–based products will reach multicenter clinical trial stage, and we will start to see efficacy data.”

Using NK-Cells in Cancer Care Dahlberg and colleagues began their review by discussing the role of NK-cells in cancer. These types of cells recognize tumor cells by certain activating receptors, including natural cytotoxicity receptors that detect altered expression of their ligands on the tumor cell surface. Other mechanisms to trigger NK-cells include downregulation or lack of major histocompatibility complex (MHC) class I molecules on the cell surface of tumor cells, as well as mechanisms of action after these cells have been triggered, including upregulation of Fas

ligand on the NK-cell surface, which can lead to apoptosis of the tumor cells. However, tumors, including acute myeloid leukemia (AML), have gained the ability to evade NK-cells, according to the authors. The evasion of those cells in cancer has been associated with several mechanisms, including reduced natural cytotoxicity receptor surface expression, and upregulation of nonclassical MHC class I molecule human leukocyte antigen (HLA)-G. Furthermore, research in patients with cancer has indicated that NK-cells themselves may develop abnormalities. These include defective expression of activating receptors, which has been observed in several cancers, including hepatocellular carcinoma, metastatic melanoma, AML, chronic lymphocytic leukemia, and multiple myeloma. Defective NK-cell proliferation also has been observed in patients with metastatic renal-cell carcinoma and chronic myelogenous leukemia, whereas decreased NK-cell activity has been seen in patients with renal-cell carcinoma.

NK-Cell–Based Products Furthermore, the authors discussed clinical-grade NKcell products, as well as various sources of NK-cells. Most NK-cell–based products originate from peripheral blood mononuclear cells. Other sources include umbilical cord blood, cell lines, and human embryonic stem cells, as well as induced pluripotent stem cells. In addition, Dahlberg and colleagues emphasize the important role of cytokines in ex vivo manufacturing of NK-cell–based products. In this setting, cytokines stimulate, differentiate, activate, and expand NK-cells. Interleukin (IL)-2 is one of the most popular cytokines used for this purpose. IL-15 is another important cytokine, because it is required for NK-cell maturation and survival. Other factors to consider when achieving clinically relevant NK-cell numbers, viability, and tumor cytotoxicity include the expansion platform, cell culture media, and serum supplementation. NK-cell–based anticancer products have been used in the clinical studies of a wide range of patients with cancer, the authors continued. Adoptive autologous NK-

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cells have been studied in patients with breast cancer, lymphoma, glioma renal-cell carcinoma, non–small-cell lung cancer, and adenocarcinoma. Data show that these cells are safe and have no toxic side effects. Some clinical trials have shown that these types of cells only have partial effects on certain tumors, or do not lead to an improvement in patients with metastatic carcinoma or relapsed lymphoma. Another NK-cell–based anticancer product is allogeneic NK-cell products, which have been used to treat patients with leukemia, renal-cell carcinoma, leukemia, colorectal cancer, hepatocellular cancer, lymphoma, and melanoma. However, the authors noted that the risk associated with allogeneic NK-cell transplantation is graftversus-host disease. Precautions should be taken to reduce this risk, including immunosuppression, infusion of CD3-depleted high-purity NK-cells, and selecting the donor that matches the host HLA. Dahlberg and colleagues then discuss immune suppression of NK-cells in the tumor microenvironment, noting that the efficiency of NK-cells targeting solid tumors has not been fully seen in the clinical setting.

Novel Uses for NK-Cells Taking a closer look at future therapies, Dahlberg and colleagues review the use of genetically modified NKcells. In particular, they explain that the specificity of NK-cells can be enhanced to the target cells by modifying them to recognize antigens specifically expressed on tumor cells. In particular, studies have shown that NKcells that have been genetically modified to produce IL-2 or IL-5 cytokines have increased survival and proliferation, and enhanced activation and antitumor activity in vivo. The study authors also mention using another approach to genetically modify NK-cells, where tumor specificity can be enhanced via antibody-dependent cellular cytotoxicity. Monoclonal antibodies (mAbs), including anti-CD20 (rituximab), anti–human epidermal growth factor receptor 2 (trastuzumab), anti-CD52 (alemtuzumab), anti– epidermal growth factor receptor (cetixumab), and anti-CD38 (daratumumab), have been developed to target specific tumor antigens. Dahlberg and colleagues go into detail about the uses of these therapies in different populations of patients with cancer. For example, they reported mild, infusion-related reactivity, and complete or very good partial responses with reduced bone marrow plasma cell levels in patients with relapsed myeloma who were treated with daratumumab. Furthermore, research has shown that combination therapy with mAbs, along with existing treatments, may enhance NK-cell activity in antitumor therapy. Several clinical trials have evaluated the use of completely human IgG4 anti–killer cell

immunoglobulin-like receptor antibody (IPH-2101) as a single treatment, or in a combination, among patients with hematologic diseases. To enhance NK-cell tumor reactivity, bi- and tri-specific antibodies cross-linking CD16 with tumor-specific mAbs have also been engineered from chimeric antigen receptors (CARs). In addition, the authors discuss the use of CARs fused with intracellular lymphocyte stimulatory molecules to create high-affinity, specific recognition of tumor antigens and tumors. The use of CARs has been extensively studied and has led to several phase 1 and 2 clinical trials. Only 2 clinical trials looking at CAR NK-cells have been approved, they noted. Immunomodulatory drugs (IMiDs), including thalidomide, lenalidomide, and pomalidomide, are another area of future research. These drugs can simulate NK-cells and T-cells, and may be better able to target cancer cells.

“NK-cell–based therapies are, in theory, complementary to many different upfront, maintenance, and late-line therapies.” —Carin I. M. Dahlberg, PhD, and colleagues Combining NK-cell products along with other drugs that directly target tumor cells or modulate the cytotoxic activity of NK-cells may be useful if further research indicates that NK-cell products cannot fully eliminate tumor cells as a result of the immunosuppressive effects of the tumor microenvironment, or in vivo expansion and cytotoxicity. mAbs and IMiDs may be used together with NK-cell products to enhance tumor targeting and elimination. In addition, combination therapy with NK-cell–stimulating cytokines (IL-2, IL12, IL-15, and IL-21) could be used to enhance NKcell–mediating killing. NK-cell infusions plus chemotherapy could also be used as an alternative combination to overcome tumor-induced dysfunctions. “NK-cell–based therapies are, in theory, complementary to many different upfront, maintenance, and late-line therapies,” Dahlberg and colleagues concluded. “Further studies clarifying the complementary efficacies and synergies have to be initiated to conclusively state if there is any place for these intriguing cells in [the] search for an effective treatment of cancer.” u

Reference

Dahlberg CI, Sarhan D, Chrobok M, et al. Natural killer cell-based therapies targeting cancer: possible strategies to gain and sustain anti-tumor activity. Front Immunol. 2015;6:605.