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As CLN Stat has reported previously, immunotherapy continues to gain ground in the fight against cancer, particularly melanoma. Now research finds success harnessing the body’s immune system against Merkel cell carcinoma, head and neck cancer, and B-cell acute lymphoblastic leukemia.

Two such studies were presented at the American Association for Cancer Research’s annual meeting in April.

One study, which was simultaneously published in The New England Journal of Medicine, reported the results of a Phase 2 clinical trial of pembrolizumab, an immune checkpoint blocking drug that blocks the PD-1 protein. The protein is found on the surface of immune system T cells. Blocking it allows the immune system to identify the cancer cells as foreign and destroy them. Pembrolizumab is approved for treating advanced lung cancer and melanoma.

In this study, investigators enrolled 26 patients with recurrent or metastatic virus-linked Merkel cell carcinoma. All had already undergone standard chemotherapy and/or radiation therapy, but none had received systemic therapies for the advanced disease.

Participants received pembrolizumab intravenously every 3 weeks for a median follow-up time of 33 weeks. Imaging showed that 56% (14 of the 25 who completed the trial) responded to the drug, with four experiencing a complete response. Sixty-three percent of those who responded had virus-linked cancer, compared with 44% whose cancers were not linked to the virus, suggesting that this class of drugs may be effective in other virus-associated cancers.

In the second study, 240 patients with relapsed or metastatic head and neck cancer were randomized to nivolumab, another PD-1 inhibitor, and 121 patients to one of three chemotherapies. After 1 year, 36% of those treated with nivolumab were still alive compared with 17% of the control group, for a median survival of 7.5 months vs 5.1 months. Patients who tested positive for the HPV virus, however, survived more than twice as long as those who were HPV-negative (9.1 vs. 4.4 months). Fewer patients on nivolumab experienced severe side effects (13 percent vs. 35 percent).

The trial’s principal investigator, Kevin Harrington, professor of biological cancer therapies at The Institute of Cancer Research in London, called the results “a potential game changer for head and neck cancer.”

Another recently published study found that 27 of 29 patients with B-cell acute lymphoblastic leukemia who received infusions of their own genetically modified T cells demonstrated no detectable signs of disease within a month. The study was published online in the Journal of Clinical Investigation in late April.