AACR Annual Meeting 2016: Exciting Immunotherapy Advances Confirm Long-term Benefit, Offer Hope for More Cancer Types
Immunotherapy was one of the hottest topics at last year’s AACR Annual Meeting, and this year the trend is continuing. Among the presentations on immune checkpoint inhibitors was a study featuring long-term survival data from a nivolumab (Opdivo) trial, one on a new use for nivolumab, and yet another on a new use for pembrolizumab (Keytruda). These results emphasized that immunotherapies have not just arrived, they are here to stay.
Five-year survival rates in melanoma patients treated with nivolumab much higher than historical rates
Medical oncologist F. Stephen Hodi, MD, of Harvard Medical School presented the first long-term follow-up data and analysis from a phase I clinical trial, in which metastatic melanoma patients were treated with the anti-PD-1 immunotherapy nivolumab for up to two years.
Trial results showed that more than one-third of metastatic melanoma patients (34 percent) who received the anti-PD-1 immunotherapeutic nivolumab are still alive five years after starting treatment. These results are exciting, given that the five-year survival rate for metastatic melanoma patients diagnosed between 2005 and 2011, according to the National Cancer Institute’s SEER data, was 16.6 percent. The immunotherapy has doubled this statistic in this clinical trial.
The overall survival 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 in an interview.
“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.”
Data from a phase III trial shows nivolumab is effective against head and neck cancers
Results from the phase III clinical trial, CheckMate-141, showed nivolumab improved the survival rate in patients with recurrent or metastatic head and neck squamous cell carcinoma that progressed after platinum-based chemotherapy, compared with single-agent chemotherapy of the investigator’s choice.
At 12 months, 36 percent of the patients treated with nivolumab were alive compared with 17 percent of those assigned therapy of investigator’s choice. Patients treated with nivolumab had an overall response rate of 11.7 percent, compared with 7.4 percent in those who received chemotherapy of investigator’s choice.
“This study is the first randomized clinical trial to clearly demonstrate improved overall survival for patients with platinum-refractory recurrent or metastatic head and neck squamous cell carcinoma,” said Maura L. Gillison, MD, PhD, a professor at The Ohio State University Comprehensive Cancer Center, who presented this study. “We hope that the results will establish nivolumab as a new standard-of-care option for this patient population and thereby fulfill a huge unmet need.”
The effect of nivolumab on overall survival was seen for both patients with human papillomavirus (HPV)-positive disease and those with HPV-negative disease. Given that certain types of head and neck squamous cell carcinoma have been linked to HPV infection, these results are promising.
“We are hopeful that this represents the tip of the iceberg with regard to future benefit of immunotherapy for patients with head and neck squamous cell carcinoma,” Gillison said.
Pembrolizumab promising for patients with advanced Merkel cell carcinoma
Data from a phase II clinical trial showed that many patients with advanced Merkel cell carcinoma, an aggressive type of skin cancer, who received the immunotherapeutic pembrolizumab as first-line therapy had durable responses. Responses were seen in those whose cancers were driven by a virus as well as those whose cancers were induced by exposure to ultraviolet (UV) light.
Merkel cell carcinoma is a rare, aggressive type of skin cancer, and Merkel polyomavirus (MCPyV) is the driving factor in about 80 percent of the cases, said medical oncologist Paul Nghiem, MD, PhD, from the University of Washington School of Medicine and Fred Hutchinson Cancer Research Center. This type of skin cancer is 35-fold less common than melanoma, but on average, it is about three times more likely to kill a patient than melanoma. Response to chemotherapy is typically quite brief and half of patients develop progressive disease within three months of initiating treatment, he added.
“In this clinical trial, patients with metastatic Merkel cell carcinoma who received pembrolizumab had an objective response rate of 56 percent, which is similar to chemotherapy outcomes, but the duration of response to pembrolizumab appears to be significantly longer than that for chemotherapy,” Nghiem said.
“Currently there are no FDA-approved drugs for the treatment of MCC. We are expanding this trial to recruit additional patients and we hope that these data will contribute to meaningful new therapeutic options becoming available for these patients,” he added.
These stories are picking up national media attention, including a piece in the Washington Post.