By BISHAL GYAWALI MD
Me-too deja vu
I read the report of a phase 3 RCT of a “new” breast cancer drug but I had the feeling that I had already read this before. Later I realized that this was indeed a new trial of a new drug, but that I had read a very similar report of a very similar drug with very similar results and conclusions. This new drug is a PARP inhibitor called talazoparib and the deja vu was related to another PARP inhibitor drug called olaparib tested in the same patient population of advanced breast cancer patients with a BRCA mutation. The control arms were the same: physician choice of drug, except that physicians couldn’t choose the one drug that is probably most effective in this patient population (carboplatin). The results were nearly the same: these drugs improved progression-free survival, but didn’t improve overall survival. In another commentary, I had raised some questions on the choice of control arm, endpoint and quality of data about the olaparib trial when it was published last year. This current talazoparib trial is so similar to the olaparib trial that you can literally replace the word “olaparib” with “talazoparib” in that commentary and all statements will stay valid.
The oncology version of half-full, half-empty glass
The PARP inhibitors olaparib and niraparib are also approved in ovarian cancer based on improvement in progression-free survival (PFS), without improving overall survival (OS). If a drug doesn’t improve OS but improves only PFS, it should also improve quality of life to justify its use. According to two new reports, these drugs do not appear to improve quality of life. The niraparibtrial reported that the patients were able to “maintain” their quality of life during treatment while the olaparib trial reported that olaparib did not have a “significant detrimental effect” on quality of life. I find it remarkable that a drug that isn’t proven to improve survival is lauded for not significantly worsening quality of life … at $10,000 a month!
It is also important to recognize that these drugs were tested as maintenance therapy against placebos. For “maintenance therapies,” as explained in this paper, improving PFS alone is not an important endpoint. That’s why I am also not excited about this new trial of sorafenib maintenance in ovarian cancer. A drug has to be very ineffective to fail to improve even PFS as a maintenance therapy against placebo.