This has prompted urgent global scientific collaboration on therapies and drugs. The advances in immunotherapy – a modality that reduces cancer’s insidious ability to block the body’s natural immune defences – emerged from such collaboration. In mid-February this year, the European Society of Medical Oncology held its summit at Century City in Cape Town where global experts, some of them South African, shared the latest therapeutic advances.
Two cancers where immunotherapy excels, or dramatically boosts more traditional treatments - thereby possibly prolonging more lives - are advanced lung and skin cancer (melanomas).
Worldwide, lung cancer is the leading cause of cancer death. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined.
While in every three cancers diagnosed is a skin cancer. By using immunotherapy drugs, up to 25% to 30% more of selected melanoma patients are now surviving up to eight years longer than with traditional treatments alone, says Professor Bernardo Rapoport, medical oncologist and extraordinary professor of immunology at the University of Pretoria says. With immunotherapy drugs, one in four melanoma patients survives.
Additionally, half of non-small cell lung cancer patients with a PD-L1 expression on at least 50% of tumour cells) survives at least two years, says Rapoport.
In a trial of one immunotherapy drug registered in South Africa two years ago, 20% of patients with advanced malignant melanoma continued living for longer than five years. The median survival rate for patients with identical advanced disease using chemotherapy or radiation was less than 18 months. “I have three or four (immunotherapy-treated) patients still alive after 10 years,” says Dr Daniel Vorobiof, founder of the Sandton Oncology Centre.
In a five-year study of advanced lung cancer using immunotherapy, 16% of patients were still alive after five years. “With the best existing chemotherapy, almost all of them could be dead within five years,” says Professor Alex Adjei, a principal clinical investigator at the Mayo Clinic.
The trio of oncology experts say that immunotherapy has the a lot of potential to cure cancer but caution that current research is focussed on understanding why some patients have dramatic benefits and others none. Immunotherapy candidates are assessed using biomarkers which reveal an individual’s built-in propensity to respond favourably or not.
Asked to roughly quantify how widely immunotherapy is being used, either in clinical trials or expanded access programs, Rapoport puts it at roughly 95% chemotherapy, radiation or surgery, versus five percent Immunotherapy. However, he believes that within 15 years, this equation will be reversed.
