Promising signs for long-term impact of cancer immunotherapy, says 2022 Stevens Lecturer
The signs are promising that immunotherapy could cure certain advanced-stage cancers in some patients, a leading oncologist has said.
Professor James Larkin, a consultant medical oncologist at The Royal Marsden Hospital, delivered the 2022 Stevens Lecture at the Royal Society of Medicine last week (Tuesday 17 May). He told the audience that the pioneering treatments are “probably curative” in some patients with advanced cancer - but the drugs are still too new for us to know definitively.
He shared the results of studies into patients with metastatic skin and kidney cancers, which seem to respond best to the treatment. Metastatic cancers are those at the most advanced stage and that have spread around the body. Just a decade ago, the average survival time for a patient with metastatic melanoma (skin cancer) would have been six-to-nine months. However, clinical trials have shown that a class of immunotherapy drugs called immune checkpoint inhibitors increases the chance of long-term survival to 20-to-50 per cent.
As trials of such drugs only began around 15 years ago, it is too early to assess the overall effect on lifespans and therefore researchers are cautious about calling it a cure - yet. Professor Larkin said: “Historically, almost all metastatic solid tumours were incurable. I think checkpoint inhibitors are probably curative in some patients with advanced melanoma, as well as kidney and lung cancers. But, ultimately, we need further follow up. We just need to see what happens in the long term.”
The early data is showing that patients treated with this drug who survive to three years have a good chance of making it to five, ten or more years. Professor Larkin referred to a Stage 4 melanoma patient he treated in the early days of clinical trials in 2005, who is now leading a completely normal life 17 years later.
The human body has natural processes for regulating the immune system and stopping it from running rampant and causing damage. The drugs work by inhibiting these processes and, in doing so, unleashing the immune system to recognise and destroy cancer cells. The discovery of the therapy won James P. Allison and Tasuku Honjo the 2018 Nobel Prize in Medicine.
Professor Larkin was optimistic about the future but said that more research is needed into: side effects; finding successful immunotherapies for other cancers; and identifying which patients are most likely to benefit. He said: “The success of immune checkpoint inhibitors really has revitalised cancer immunotherapy and I hope and expect to see further significant progress in the next 15 years or so.”
Professor Roger Kirby, President of the Royal Society of Medicine, introduced Professor Larkin and presented him with the 2022 Stevens Medal, following his lecture. Professor Kirby called the work “miraculous”. He said: “In my lifetime, the outcomes for these patients who seemed destined to die has been completely transformed by these treatments.”
The Stevens Lecture has been given annually at the RSM since 1970 by a leading medical professional on a topic of interest to the general public.