Leaked Conference Article Shows Pfizer’s Positive Phase I Prostate Cancer Data

Pfizer’s experimental drug mevrometostat cutting disease progression rates in half in combination with standard hormone therapy, according to an article describing data from a Phase I trial of metastatic castration-resistant prostate cancer that appeared on Monday morning on the website for the ASCO Genitourinary Cancers Symposium.

The only issue is that the team from Pfizer wasn’t going to speak about the data until Thursday. Later in the day Monday, the conference published a full study abstract.

In addition to reducing disease progression rates, mevrometostat cut the risk of death by 49% in trial participants, all of whom had already received hormone treatment and one round of chemotherapy, according to reporting from Endpoints News.

Adverse effects were diarrhea (78% of patients), decreased appetite (58.5%) and dysgeusia (58.5%).

Pfizer is currently recruiting for two Phase III trials, MEVPRO-1 and MEVPRO-2, testing mevrometostat, an inhibitor of the oncoprotein EZH2, in prostate cancer as well.

Castration-resistant prostate cancer is a common form of prostate cancer, often treated with androgen deprivation therapy and chemotherapy.

The results, although announced prematurely, should be welcome news for Pfizer. Analysts were already buoyant on the company, with Guggenheim analysts writing in an investor note early Monday morning, before the leak, that Pfizer beat their fourth quarter 2024 expectations as well as consensus estimates.

Pfizer has a number of critical updates from its oncology pipeline coming down the pike this year. Phase III data for vepdegestrant in treating breast cancer and danuglipron for obesity are expected later this quarter, as well as Padcev in combination with pembrolizumab for bladder cancer sometime this year. On Monday, Pfizer announced data showing that Padcev in combination with Merck’s Keytruda reduced the risk of death by 49% in urothelial cancer compared to chemotherapy.