A combination of two immunotherapy drugs is safe to give to patients with melanoma, a type of skin cancer, that has spread to the brain, and could help control the disease.
Melanomas that had spread to the brain responded to, or were kept stable, by the drugs ipilimumab (Yervoy) and nivolumab (Opdivo) in around half of patients, according to an early look at unpublished results from two clinical studies.
While patient numbers were small, the results could offer a new treatment option if confirmed in future studies.
Dr Lynn Mara Schuchter, from the University of Pennsylvania in the US, said the findings 'could be practice changing'. But she added that patients now need to be followed up for longer.
Schuchter said that larger clinical trials would be needed to confirm the potential benefit for these patients, and to work out when is the best time to offer this treatment.
The findings were presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago in the US.
Little is known about how immunotherapy might be able to help control melanoma that has spread to the brain, a common complication in patients diagnosed with late stage disease.
Patients whose disease has spread to the brain have been ineligible for previous clinical trials of immunotherapy for melanoma.
The phase 2 CheckMate 204 study , led by Dr Hussein Abdul-Hassan Tawbi from the University of Texas MD Anderson Cancer Center, and the phase 2 Anti-PD1 Brain Collaboration (ABC) trial , led by Professor Georgina Long from the University of Sydney, specifically recruited patients with melanoma that had spread to the brain. Most of these patients weren't experiencing symptoms as a result of the tumours in their brains.
Of the 75 patients treated on the CheckMate 204 study, 60 percent saw the disease in their brain respond to the combined treatment, or be kept stable by it, at the middle point of follow-up, which was 9.2 months.
16 patients (21 percent) saw the disease in their brain completely disappear following treatment.
Professor Peter Johnson, Cancer Research UK's chief clinician, said the results of the CheckMate 2014 study "suggest that a combination of the immunotherapy drugs nivolumab and ipilimumab is safe and effective against skin cancer that's spread to the brain."
"Radiotherapy can have limited benefits, so these results are encouraging and may be another option for some patients in the future once larger trials are done," he added.
On the ABC trial, 42 percent of the 26 patients treated saw the disease in their brain respond to some degree to the combined immunotherapy drugs at the middle point of follow-up, which was 16.4 months after treatment. This increased to 50 percent when looking at 20 patients who had not previously been treated with a targeted cancer drug for melanoma, suggesting the immunotherapy combination may work better upfront, although these numbers are small.
4 patients (15 percent) saw the disease in their brain completely disappear following the combined immunotherapy treatment.
Six months after treatment, 67 percent of patients on the CheckMate 204 study hadn't seen their disease get worse, so-called progression free survival. On the ABC trial this was 46 percent.
Schuchter said that while these early results were 'fantastic', most patients on these studies did ultimately see their disease get worse. And across the different study groups between a quarter and half of patients who took part have died.
According to both lead researchers and Schuchter, the side effects experienced by patients on these studies were as expected for immunotherapy treatment of melanoma. But in some cases these can be serious, and must be carefully managed.
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More information: Efficacy and safety of nivolumab (NIVO) plus ipilimumab (IPI) in patients with melanoma (MEL) metastatic to the brain: Results of the phase II study CheckMate 204. abstracts.asco.org/199/AbstView_199_181375.html
A randomized phase II study of nivolumab or nivolumab combined with ipilimumab in patients (pts) with melanoma brain metastases (mets): The Anti-PD1 Brain Collaboration (ABC). abstracts.asco.org/199/AbstView_199_187928.html