Terminally ill cancer patients have been given new hope as clinical trials reveal broad success for a revolutionary treatment.
Patients with advanced bladder, head and neck cancer, and classical Hodgkin lymphoma were among those whose lives were extended by immunotherapy, the recent American Society of Clinical Oncology Annual meeting in Chicago revealed.
Unlike surgery, radio or chemo, immunotherapy doesn’t directly target cancer cells. Instead, it retrains the immune system, which finds pathogens but doesn’t see cancer cells, to fight them.
Some cancer cells, for instance, multiply aggressively because they produce a signal called PD-L1 which deactivates the immune cells around them. Immunotherapy drugs called checkpoint inhibitors block that signal and free immune cells for the cancer-fighting cause.
While immunotherapy was shown last year to improve survival for patients with melanoma and lung cancer, success has now been revealed for other types, including hard-to-treat cancers.
One example is bladder cancer, estimated to affect 76,000 people in 2016 the US alone. The five-year survival rate is just 15%, if the disease is diagnosed in its advanced stages.
In two trials of previously treated metastatic bladder cancer patients, the immunotherapy drugs atezolizumab (brand name Tecentriq), which was FDA approved last month, and nivolumab (brand name Opdivo), shrunk tumours by 30% in at least a fifth of patients.
And on nivolumab, 45.6% of bladder cancer patients survived for at least a year, a follow-up study showed – “better than anything we’ve seen in the past”, according to oncologist Padmanee Sharma, who was involved in the trial.
Another checkpoint inhibitor called pembrolizumab (brand name Keytruda) was tested on heavily pre-treated patients with reoccurring or metastatic head and neck cancer, an “extremely difficult disease to treat”, according to Ranee Mehra, head and neck oncology at Philadelphia’s Fox Chase Cancer Center.
In this study, 18% of 192 patients responded with either partial or full remission of tumours, and 65% of the responders continued to respond for 30 months. Merck has applied for Keytruda approval for metastatic head and neck cancer, which will be reviewed under the FDA’s Accelerated Approval program.
Other cancer types reported to respond to immunotherapy included metastatic anal cancer and advanced kidney cancer. Success was also reported for classical Hodgkin lymphoma – a trial showed 66% of 80 patients responded to nivolumab with partial or full remissions after their cancer had progressed following stem cell transplants and chemotherapy.
A problem remains that only around a fifth of cancer patients respond to immunotherapy. So researchers are combining these therapies together or with chemotherapy drugs to drive up success rates.
One of these combinations is already FDA-approved for advanced melanoma – ipilimumab (trade name Yervoy) and nivolumab, which block two different signals that deactivate immune cells. The two-year survival rate for melanoma patients treated with both drugs was 69%, compared to 53% on ipilimumab alone, a trial revealed. Two-year survival rates for metastatic melanoma patients between 2004 and 2009 have been reported to range between 9% and 40%.
“There are multiple things happening in the tumour micro-environment and in the cancer itself, so we need to come in with a multi-pronged attack,” Jill O’Donnell-Tormey, CEO of the non-profit Cancer Research Institute in New York, told Forbes.
“That’s what’s exciting about these combinations—we’re starting to come in from different angles and different mechanisms.”
One of the most exciting of the conference’s presentations, according to the conference’s chief medical officer Richard Schlisky, was a large myeloma trial.
Patients with relapsed or previously unresponsive multiple myelomas were jabbed with both the immunotherapy drug daratumumab (brand name Darzalex) and standard chemotherapy. Those receiving daratumumab had a 61% lower risk of death or cancer progression than those who received chemotherapy alone. The drug also doubled the number of patients that showed no sign of any remaining cancer from 9% to 19%.
“Overall the future for all of these immunotherapy approaches is bright,” said O’Donnell-Tormey. “We’re continuing to see immunotherapies expand to larger patient populations and different cancer types. I think this is potentially going to be a way to treat all cancers.”
Viviane Richter is a freelance science writer based in Melbourne.
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