On Tuesday, the US Food and Drug Administration approved the first-ever immunotherapy drug (pembrolizumab) that can treat solid tumors anywhere in the body as long as the tumor has the matching genetic biomarker.
The clinical trial data showed the immunotherapy drug pembrolizumab induced complete or partial tumor shrinkage in around 40% of patients with one of 15 end-stage cancers. For 78% of the patients who responded to the drug, the tumor shrinkage lasted for six months or longer. In a separate clinical trial it was found that in 57% of late-stage cancer patients, pembrolizumab halted tumor growth or induced tumor shrinkage, and 80% of the patients were still alive a year after starting the drug. Pembrolizumab went through the Food and Drug Administration’s accelerated approval process as they considered it likely to benefit late-stage cancer patients, often patients who are left with no other treatment options.
Pembrolizumab works by blocking the PD-1/PD-L1 cellular pathway and had previously been approved by the Food and Drug Administration to treat head and neck cancer, melanoma, Hodgkin’s lymphoma and lung cancer.
The Food and Drug Administration’s announcement is a major step for targeted cancer therapies as it demonstrates the promise of drugs that target specific genetic biomarkers for cancers regardless of their location within the body. The biomaker that Pembrolizumab targets is prevalent in colon and intestinal cancers, and is also occasionally found in prostate, bladder, thyroid and breast cancers. An estimated 1 in 20 late-stage cancers have the required genetic biomarker for Pembrolizumab.
These are still very early days for immunotherapy but the field is moving so fast that scientists and regulators are struggling to keep up. There are currently multiple clinical trials for other cancer immunotherapies taking place around the world. Drugs like Pembrolizumab are showing the promise of targeted drugs but also the need to increase investment and research funding to enable scientists and regulators to keep pace with the field’s progress.
This approval by the Food and Drug Administration will hopefully encourage a rise in industry interest in developing immunotherapies and other targeted cancer therapeutics. In the near future, machine learning could also play a pivotal role in speeding up this type of research by rapidly identifying useful molecular pathways for cancer drugs to exploit.