A new cancer drug has potential to help shrink or eradicate tumors in patients whose cancer had resisted every other form of treatment.
The drug is the happy result of a failed trial. A nearly identical drug, nivolumab, was given to 33 colon cancer patients, and just one showed any response — but his cancer vanished altogether.
What was special about that one patient? The man’s cancer cells contained a plethora of mutated genes, which produced thousands of strange-looking proteins on the surfaces of the cells. Once the tumor’s cloaking mechanism was short-circuited by the drug, the man’s immune system had no trouble targeting the foreign proteins on the cancer cells.
That led to the idea for the Dr. Diaz’s new study. He and his colleagues sought patients whose tumors had the same genetic defect, which can arise in any of four genes in a pathway that repairs damaged DNA.
The study followed 86 cancer patients with tumors of the pancreas, prostate, uterus or bone. Each patient was given pembrolizumab, which also goes by the brand name Keytruda.
After taking the drug, 66 patients had their tumors shrink substantially and stabilize, instead of continuing to grow. Among them were 18 patients whose tumors vanished and have not returned.
According to the New York Times, this is the first time a drug has been approved for use against tumors that share a particular genetic profile, regardless of where they appear in the body.
Dr. Jack Jacoub, a medical oncologist and director of thoracic oncology at Memorial Care Cancer Institute at Orange Coast Memorial Medical Center, said “The FDA doesn’t take these kinds of things lightly. The data was so good, they had to approve it.”
The Drug is now being marketed by Merck & Co. Pharmaceutical, and will cost approximately $100,000 per year.