PHILADELPHIA & MADISON, Wis.--(BUSINESS WIRE)-- Context Therapeutics, a clinical-stage biopharmaceutical company dedicated to advancing treatments for hormone driven cancers, today announced a Phase 2 clinical collaboration with the Wisconsin Oncology Network. This clinical collaboration will evaluate whether the addition of Apristor to the antiestrogen, fulvestrant, can enhance outcomes for patients with metastatic breast cancer whose cancer has progressed on prior therapies.

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The Phase 2 trial will assess the combination of the progesterone receptor antagonist, Apristor (onapristone ER) plus the antiestrogen, Faslodex^® (fulvestrant), in up to 40 patients who have ER+,PR+, and HER2- tumors and who have received prior antiestrogen (aromatase inhibitor) plus CDK4/6 inhibitor treatment. The primary endpoint will be overall response rate (ORR), which is the proportion of patients who have either a complete or partial response. To further characterize the activity of Apristor, secondary endpoints will include duration of response, clinical benefit rate, and progression-free survival (PFS). In addition, this study will evaluate the safety and pharmacological profile of the combination in these patients, as well as biomarker and functional imaging analyses to explore predictive factors of response to complete hormone blockade. This data will support Context’s ongoing Phase 2 studies and help design a future Phase 3 trial.

“Currently, there are limited therapeutic options to treat hormone driven breast cancer in the advanced setting. Recent preclinical findings in models of antiestrogen and/or CDK4/6 inhibitor resistance give us reason to believe that Apristor when combined with an antiestrogen can provide complete hormone blockade and help women with ER+,PR+,HER2- breast cancers,” said Martin Lehr, CEO of Context Therapeutics. “We are humbled by the enthusiasm and support of Wisconsin Oncology Network (WON), coordinated out of the University of Wisconsin Carbone Cancer center, a leading breast cancer clinical consortium in the Midwest. The skill and scale of WON, under the leadership of Drs. Ruth O’Regan, Ryan Mattison, and Kari Wisinski, gives our company tremendous confidence that WON will maximize patient access to this important trial.”

The study will be coordinated by the Study Chair, Dr. Sailaja Kamaraju, an Associate Professor of Medical Oncology at the Medical College of Wisconsin, and study’s Primary Investigator, Dr. Kari Wisinski, Associate Professor of Medical Oncology at the University of Wisconsin Carbone Cancer Center. Final study design and other details will be announced upon enrollment of the first patient, expected in early 2020.

“The majority of breast cancer patients have hormone driven breast cancer. The hormones estrogen and progesterone drive breast cancer progression in those patients, but antiestrogens are the only antihormonal therapy available to clinicians. Therefore, treatment of those patients to date has consisted of antiestrogens alone or in combination with agents, including CDK4/6 inhibitors, that enhance the antitumor activity of antiestrogens. Given the broad use of antiestrogens, antiestrogen resistance is now a major clinical challenge,” said Dr. Kamaraju. “We believe that a progesterone receptor antagonist has the potential to address antiestrogen resistance, which we believe will lead to better outcomes for patients. This study, run in parallel with other Apristor breast cancer studies, including a window of opportunity (neoadjuvant) study at SOLTI and a first line (1L) biochemical recurrence study at Memorial Sloan Kettering Cancer Center, will provide clinicians with a complete picture of how Apristor works in advanced ER+,PR+,HER2- breast cancer and inform the design of a future Phase 3 trial.”

About Hormone Driven Breast Cancer

Hormone receptor positive (HR+) breast cancer is the most common form of breast cancer and accounts for more than 70% of all breast cancers. Metastatic HR+ cancer is usually treated with antiestrogen therapies first that help stop tumor growth. For many patients, antiestrogen therapy becomes ineffective over time and the cancer becomes resistant to antiestrogen therapy. In this recurrent setting, progesterone receptor has emerged as a prominent resistance mechanism. It is estimated that there are over 750,000 patients with recurrent disease worldwide.

About Wisconsin Oncology Network

The Wisconsin Oncology Network (WON) is a regional network of 19 sites that allows community health centers to enroll patients in select cancer clinical trials that are open at the University of Wisconsin Carbone Cancer Center. Non-UW sites account for nearly 40% of accrual to WON clinical trials. To date, more than 2,200 patients have participated in WON studies, leading to multiple publications and scientific presentations.

About Apristor

Apristor (onapristone extended release) is a potent and specific antagonist of the progesterone receptor that is orally administered. Currently, there are no approved therapies that selectively target PR+ cancers. Preliminary preclinical and clinical data suggest that Apristor has anticancer activity by inhibiting the binding of progesterone receptor to chromatin, downregulating cancer stem cell mobilization, and blocking immune evasion. Apristor is an investigational drug that has not been approved for marketing by any regulatory authority.

About Context Therapeutics

Context is a clinical-stage biopharmaceutical company advancing medicines to treat hormone driven cancers. Context’s lead program is Apristor, an investigational Phase 2 drug that is being developed for progesterone receptor positive (PR+) metastatic breast, ovarian, and endometrial cancers. For more information on Context, visit www.contexttherapeutics.com.

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