There is though no single treatment or medicine to the problem, but there have been some that have shown their effectiveness in its treatment.
Medical Cannabis being one of them. There have been researches that have highlighted the benefits of medical marijuana in treatment of cancer. It helps the cancer patients with reducing anorexia, vomiting, and nausea. It also helps those living with HIV. More info at: https://onlinemedicalcard.wordpress.com/2019/02/06/is-medical-marijuana-the-cure-to-cachexia/