After a late stage trial showed the beneficial effects of an immunotherapy drug called Keytruda on some head and neck cancer patients, the Food and Drug Administration (FDA) has approved the drug for those patients.
The FDA said that Keytruda can be used either alone or in combination with a common chemotherapy regimen for patients with relapsed head and neck cancer. Keytruda itself is an immunotherapy drug, meaning it uses the body's own immune system to attack the cancer.
Read MoreUsually patients with relapsed head and neck cancer are treated with a combination of two chemotherapy drugs and a targeted antibody. A targeted antibody is a drug that blocks cancer cell growth my interfering with specific targeted molecules, and the chemotherapy component is aggressive to the point of being characterized "extreme."
In the study, led in the UK by a team at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, researchers first looked at patients patients with higher levels of PD-L1. PD-L1 is a protein that suppresses the immune system.
Patients with higher levels of PD-L1, who were given the immunotherapy drug pembrolizumab (Keytruda) along with chemotherapy, lived on average for 14.7 months. Patients who had aggressive chemotherapy treatments but had no immunotherapy added lived on average for 11.0 months.
Patients in the study with lower levels of the immune suppressing protein PD-L1 also benefitted from the immunotherapy treatment, but not quite as much as patients with high levels of PD-L1.
For this group, average survival for patients treated with immunotherapy and chemotherapy combined lived for an average of 13.6 months after treatment. Patients who received the standard, aggressive dose of chemotherapy without immunotherapy lived an average of 10.4 months after treatment.
And a third of patients who were treated with pembrolizumab and chemotherapy survived for three years after starting treatment, compared with only one in twelve of those receiving extreme chemotherapy and no immunotherapy.
Compared with the standard, aggressive chemotherapy treatment, immunotherapy alone (without combination with chemotherapy) can still be beneficial for anyone with the PD-L1 marker, which includes most patients with relapsed head and neck cancer.
When given the immunotherapy alone, 16.9 percent of patients responded, versus 36 percent who responded when given immunotherapy and chemotherapy combined. But this was still an improvement over the standard, aggressive chemotherapy regimen.
"For head and neck cancers, the sheer number of mutations predisposes patients to a higher response rate to immunotherapy," said Dr. Aggarwal.
"However, it's not as high as we want," she explained. "The response rate was still under 20 percent, so there is still a large subset of patients that don't benefit, and we are constantly looking for ways to improve the response rate for those patients."
When the immunotherapy did work, it worked really well, with the average duration of response to the drug lasting 22.6 months, where patients given the standard, aggressive chemotherapy regimen responded for about 4.5 months.
Another benefit of the immunotherapy drug alone is that people who received just the immunotherapy didn't experience as many side effects as people on the standard chemotherapy regimen. Only 55 percent of people treated with immunotherapy alone experienced side effects, compared with 83 percent of patients on aggressive chemotherapy who experienced side effect.
85 percent of patients who received the immunotherapy drug combined with chemotherapy, however, experienced side effects.
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