NEW YORK – Columbus, Ohio-based Sermonix Pharmaceuticals said on Wednesday that it is collaborating with Eli Lilly in an upcoming Phase II trial studying Sermonix's lasofoxifene in combination with Lilly's CDK 4 and 6 inhibitor abemaciclib (Verzenio) in estrogen receptor-positive, HER2-negative metastatic breast cancer patients who also harbor an ESR1 mutation.
The trial, which is expected to start enrolling patients in the third quarter of 2020, will evaluate the safety of the combination treatment.
Lasofoxifene is a selective estrogen receptor modulator and is Sermonix's lead investigational drug candidate. Sermonix is also studying lasofoxifene in combination with fulvestrant (AstraZeneca's Faslodex) in another Phase II trial targeting the same indication, with progression-free survival as the primary endpoint.
In preclinical studies at the University of Chicago, researchers found that the combination of lasofoxifene with CDK 4 and 6 inhibitor palbociclib (Pfizer's Ibrance) had a synergistic anti-tumor effect in tumor cells that had ESR1 mutations.
"Endocrine therapy is the backbone of combination therapies in ER-positive/HER2-negative breast cancer, and as a well-characterized compound, lasofoxifene may offer patients a potentially well-tolerated oral option alone and in combination in an area of significant unmet need," Sermonix Board Chairman Anthony Wild said in a statement.