Review on Immuno-Oncology Agents for Cancer Therapy

Until recently, cancer therapy comprised of four main types of treatment: surgery, radiotherapy, chemotherapy and targeted therapy. Over the past decade, immuno-oncology (IO) has emerged as a novel and important approach to cancer treatment through the stimulation of the body’s own immune system to kill cancer cells. This newly recognised method of treating cancer is rapidly developing, with many accelerated approvals by the US Food and Drug Administration and European Medicines Agency in 2019. Several therapeutic classes have emerged within IO, and are the focus of this review article. In particular, the immune checkpoint inhibitors have had remarkable success across multiple malignancies, and are the most well-established therapeutic class of IO agents to date. Biomarker testing for the programmed death-ligand 1 (PD-L1) checkpoint target has been developed and is now obligatory before treatment with pembrolizumab (Keytruda, Merck) when used for nonsmall-cell lung carcinoma, gastric cancer, head and neck squamous cell carcinoma and cervical cancer, as well as before treatment with atezolizumab (Tecentriq, Roche) when used for urothelial carcinoma. However, ambiguity remains as to the relevance of PD-L1 expression for checkpoint inhibition therapy for other tumour types. More recently, combining IO agents with conventional therapies has been evaluated with some significant improvements in patient outcomes. While IO agents are rapidly changing the standard of care for people with cancer, there are still many challenges to overcome in terms of managing their toxicities and ensuring that healthcare systems, such as the NHS, can afford the high cost of these therapies. The IO pipeline also includes chimeric antigen receptor T-cell therapies and cancer vaccines, both of which show great promise for the future but have their own unique toxicity and cost-effectiveness issues.