Context Therapeutics Inc. (NASDAQ: CNTX) has released data from the window of opportunity clinical study of onapristone extended-release (ONA-XR) in postmenopausal women with progesterone receptor-positive early breast cancer, indicating that ONA-XR considerably increased tumor cell proliferation suppression. The company presented the data during the 2021 San Antonio Breast Cancer Symposium.
SOLTI conducted ONAWA Study
Spanish cancer research team SOLTI conducted the phase 0 single-arm, open-label, multicentre ONAWA (SOLTI-1802) study whereby 10 participants with PR+/ER+/HER2+ negative tumor and cell proliferation marker “Ki67” above 10% were enrolled. The study evaluated ONA-XR by rate if Complete Cell Cycle Arrest determined by Ki-67 when given three weeks before surgery. The study’s secondary endpoints included safety and correlating biological activity with immunohistochemistry of tumor expression, estradiol, and progesterone blood levels and gene expression profile.
Co-principal study investigator Meritxell Bellet said, “The data from the ONAWA trial signal the potential of ONA-XR to help inhibit tumor proliferation and shift tumors to a more endocrine treatment-sensitive phenotype during treatment prior to surgery in postmenopausal women with operable breast cancer and improve overall prognosis for these patients. These results support further evaluation of ONA-XR in the treatment of early breast cancer.”
Context CEO Martin Lehr commented, “ONA-XR is being evaluated in four investigator-sponsored clinical trials in hormone-driven breast, ovarian and endometrial cancers. This readout is the first for the novel PR antagonist, and the results are encouraging early evidence of the potential of ONA-XR to offer a new therapeutic option for hormone-dependent cancers. We look forward to data updates from three other ONA-XR trials in 2022.”
Two study designs evaluating ONA-XR presented
The company also presented the design of two other clinical studies evaluating ONA-XR in metastatic breast cancer during the SABCS. They included the SMILE Study, which is a second phase study evaluating OIN-XR combination with fulvestrant for HER2- and ER+ MBC following endocrine therapy and CDK4/6 inhibitors. The other study was the Memorial Sloan Kettering Cancer Center’s Phase 1b study seeking to define tolerability, dose recommendation, and safety of ONA-XR plus letrozole and palbociclib in a phase 2 study.