More than a third of metastatic melanoma patients (34 percent) who received the anti-PD-1 immunotherapeutic nivolumab (Opdivo) in a phase I clinical trial are still alive five years after starting treatment, according to research presented at the AACR Annual Meeting 2016, April 16-20.

According to the National Cancer Institute’s SEER data, five-year survival rate for metastatic melanoma patients diagnosed between 2005 and 2011 was 16.6 percent.

“This is the first long-term follow-up analysis of data from a clinical trial testing an anti-PD-1 immunotherapy, and it is very encouraging that a subset of melanoma patients is experiencing a long-term survival benefit,” said F. Stephen Hodi, MD, director of the Melanoma Center at
Dana-Farber Cancer Institute, associate professor of medicine and investigator at the Ludwig Center at Harvard Medical School in Boston.

In a phase I clinical trial initiated in 2008, melanoma patients who had received up to five prior treatments (but not ipilimumab) received one of the five doses of nivolumab tested, which included the subsequently recommended dose of 3 mg/kg body weight, every two weeks, for up
to two years.

The median age of the patients was 61 years, and 67 percent were male.

Data from this trial, which were published in the Journal of Clinical Oncology in 2014, showed that some patients had durable responses that persisted even after discontinuation of the treatment.

The investigators followed the 107 patients for up to five years (with a minimum of 45 months of follow-up) from the time a patient received his or her first dose of nivolumab, and calculated overall survival (OS), reported at AACR.

“The five-year OS in all 107 patients was 34 percent, and OS rates appeared to plateau at around 48 months, which is indicative of long-term benefit in some patients, although more follow-up is needed to fully appreciate the benefit of nivolumab monotherapy,” Hodi said.

Survival rates were similar for the 17 patients who received the 3mg/kg dose and the remaining 90 patients who received one of the other doses (0.1 mg, 0.3 mg, 1 mg, and 10 mg nivolumab/kg), he said.

At 12 months, the OS in patients who received 3 mg/kg nivolumab was 64.7 percent, which fell to 47.1, 41.2, and 35.3 percent, at 24, 36, and 48 months, respectively, after which the survival rate plateaued.

The median OS was 20.3 months for those who received the 3mg/kg dose, versus 17.3 months in all 107 patients.

At 30 months after treatment, progression-free survival (PFS) rates were 25.7 percent for those who received 3mg/kg nivolumab and 18.6 percent for all patients.

“These data provide a foundation for establishing anti-PD-1 therapy as another standard for melanoma patients, and hopefully this would translate to other cancer types as well,” Hodi said.

Source: AACR