Pancreatic cancer pill that doubled survival may get Canada clinical trial
The head of pancreatic cancer at Princess Margaret Cancer Centre says she hopes clinical trials for a pill that could double survival time will soon be open to Canadian patients.
Medical oncologist Dr. Jennifer Knox independently reviewed a U.S.-led study of the experimental drug daraxonrasib and calls the results “amazing.”
The randomized Phase 3 clinical trial of 500 pancreatic cancer patients found those who took the daily pill survived for more than a year compared to just over six months for patients who had chemotherapy alone.
Manufacturer Revolution Medicines has applied to the U.S. Food and Drug Administration to license the drug.
Health Canada says it has not received an application to license it in Canada.
Knox says she plans to open clinical trials so as many patients as possible with pancreatic cancer can get the experimental drug without waiting for it to be licensed.
She presented her assessment of the study, which was published in the New England Journal of Medicine, at a meeting of the American Society for Clinical Oncology in Chicago on Sunday.
“I think the world expected to see that this drug would improve survival for pancreas cancer and we wouldn’t say no to any help there because so many things just don’t work,” Knox said in an interview on Tuesday.
“But to see it double the survival, I mean, it’s never been seen in pancreas cancer before.”
Pancreatic cancer has a low survival rate because it is aggressive and is often not discovered until it has spread to other organs, Knox said.
Daraxonrasib works by shutting down a protein called RAS. RAS mutations are found in more than 90 per cent of pancreas cancer cases.
“The mutation makes the RAS molecule spend all its time turned on, as opposed to cycling on, off, on, off,” Knox said.
“(Being) on all the time means it just drives everything in the cell to divide and spread and turn into the cancer.”
In addition to increasing survival, patients on daraxonrasib reported better quality of life and less pain, she said.
The most common side-effects in the study were rashes and a sore mouth.
Knox said for decades, RAS proteins causing pancreatic cancer were considered “undruggable” because there was no place for a drug molecule to attach.
Daraxonrasib works around that by attaching to cyclophilin A and the two work together to lock the RAS protein.
There are other RAS inhibitors besides daraxonrasib that show promise and she hopes to also offer those to patients through clinical trials, Knox said.
All the patients in the New England Journal of Medicine study had already been treated with a round of chemotherapy.
Knox said the next step is to offer patients a RAS inhibitor drug at the beginning of their treatment cycle, with the hope that it will work even better at that early stage.
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