Pfizer's prostate cancer drug candidate 'mevrometostat' clinical trial phase 1 results have been leaked ahead of their official announcement.
According to the published results, mevrometostat reduced the risk of death in prostate cancer patients by 49% when used in combination with another prostate cancer medication, Xtandi.
On the 11th (local time), the medical community reported that a research team led by Michael Schweizer from the University of Washington revealed the results of the phase 1 clinical trial of mevrometostat through the American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium website.
Initially, Pfizer planned to present the related data at the conference on the 13th, but due to the leak of the clinical trial results, the data was pre-released as a conference abstract.
Mevrometostat is a drug candidate developed by Pfizer as a secondary treatment for metastatic castration-resistant prostate cancer.
Metastatic castration-resistant prostate cancer refers to cancer that continues to grow even when levels of the male hormone testosterone decrease. As hormone therapy, commonly used in prostate cancer treatment, is ineffective, chemotherapy is used as the standard treatment. However, due to severe side effects associated with chemotherapy, recent developments focus on inhibitors that block the functions of proteins like PARP and LSD1 that promote cancer cell growth.
Mevrometostat has the effect of inhibiting cancer cell growth by targeting EZH2, known as a 'gene regulation switch.' EZH plays a role in regulating cell growth and differentiation by activating or inhibiting gene expression. In South Korea, Hanmi Pharmaceutical is developing next-generation anticancer drugs that simultaneously inhibit EZH1 and EZH2.
The phase 1 clinical trial results revealed this time involved 81 patients with metastatic castration-resistant prostate cancer who had prior experiences with hormone therapy and chemotherapy. Among the participants, 41 received combination treatment with mevrometostat and another prostate cancer treatment, Xtandi (active ingredient enzalutamide), while the remaining 40 were treated with Xtandi only for comparison. Xtandi is an androgen receptor inhibitor that blocks signals promoting the progression of prostate cancer.
As a result, the progression-free survival period for patients who received both mevrometostat and Xtandi was 14.3 months, which was about double that of the 6.2 months for patients who received only Xtandi. The progression-free survival period is used as a measure of the duration a patient remains alive without disease progression after starting treatment.
There were no reported deaths among the clinical trial participants; however, some side effects were observed in patients who received the combination treatment. Common side effects included diarrhea, decreased appetite, and taste abnormalities.
Dana Kennedy, head of Pfizer's Genitourinary Cancers Development Division, noted in an interview with the medical publication Endpoints, 'We confirmed that the combination therapy of mevrometostat and Xtandi enhances the effect of Xtandi and prevents resistance, improving treatment efficacy for metastatic castration-resistant prostate cancer.'
Pfizer is currently preparing for phase 3 clinical trials of mevrometostat, and is in the process of recruiting trial participants.