Context Therapeutics and World-Renowned Cancer Center Announce a Phase 2 Trial for Apristor® in Progesterone Receptor Positive Gynecological Cancers

  • Apristor® (onapristone extended release), a full
    progesterone receptor antagonist, is being studied in patients with
    rare gynecological cancers who are Progesterone Receptor Positive
  • Up to 84 PgR+ patients will be enrolled across three groups:

    • Low Grade Serous Ovarian Cancer
    • Granulosa Cell Tumor of the Ovary
    • Endometrioid Endometrial Cancer

PHILADELPHIA–(BUSINESS WIRE)–Context Therapeutics, a clinical-stage biopharmaceutical company
dedicated to advancing medicines for hormone driven cancers, today
announced the start of an open-label (NCT03909152) basket study to
evaluate the efficacy and safety of Apristor® (onapristone
extended release) in advanced gynecological tumors that are progesterone
receptor positive (PgR+). Rachel N. Grisham, MD of Memorial Sloan
Kettering Cancer Center is the study’s Primary Investigator.

The Phase 2 trial will include patients who have different PgR+ solid
tumors in advanced stages, including low grade serous ovarian, granulosa
cell, and endometrioid endometrial cancer, who have received prior
chemotherapy treatment. The progesterone receptor antagonist Apristor
will be assessed in up to 84 cancer patients. 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 Apristor in these patients, as well as biomarker analyses to
explore predictive factors of response to Apristor. Preliminary trial
results are expected in mid-2020.

“Currently, there are limited therapeutic options to treat these cancers
in the advanced setting. Recent preclinical findings, together with
Phase 1 study results in patients with advanced PgR+ ovarian and
endometrial cancers, give us reason to believe that Apristor can help
these women with PgR+ gynecological cancers,” said Tarek Sahmoud, MD,
PhD, Chief Medical Officer of Context Therapeutics. 1,2 “We
believe Apristor can make a meaningful difference for patients in the

For more information about the trial being conducted, please visit:

About Apristor®

Apristor® (onapristone extended release) is an
investigational new drug that is an orally administered full
progesterone receptor antagonist. Currently, there are no approved
therapies that selectively target PgR+ cancers. In a recent Phase 1
trial, Apristor was well tolerated and exhibited clinical benefit in
heavily pretreated patients with PgR+ endometrial, ovarian and breast
cancer. Preclinical data suggest that Apristor has anticancer activity
by blocking the activation of progesterone receptor signaling by
progesterone and/or mitogenic growth factors, inhibiting mammosphere
formation and downregulating gene signatures associated with cancer stem
cell mobilization and metastasis3,4.

About Context Therapeutics

Context Therapeutics is empowering people with cancer to take back
their lives.
Context is a clinical-stage biopharmaceutical company
advancing medicines to treat hormone driven cancers. Context’s lead
program is Apristor® (onapristone extended release), an
investigational Phase 2 drug that is being developed for progesterone
receptor positive (PgR+) metastatic breast, ovarian, and endometrial
cancers. In addition, Context is advancing CTX-30916, a pre-clinical
progesterone receptor agonist, and a discovery-stage program targeting
Sigma1. For more information on Context, visit

1 Huang, Y, et al. (2018) Inhibiting nuclear
phospho-progesterone receptor enhances antitumor activity of onapristone
in uterine cancer. Molecular cancer therapeutics17(2),
Cottu PH, et al. (2018) Phase I study of onapristone, a type I
antiprogestin, in female patients with previously treated recurrent or
metastatic progesterone receptor-expressing cancers. PLoS ONE 13(10):
Knutson TP et al. (2017) Posttranslationally modified progesterone
receptors direct ligand-specific expression of breast cancer stem
cell-associated gene programs. Journal of Hematology & Oncology 10:89.
Truong TH et al. (2019) Phosphorylated progesterone receptor
isoforms mediate opposing stem cell and proliferative breast cancer cell
fates. Endocrinology 160:430–46.


For Context Therapeutics:
Company Contact:
Martin Lehr
& Chief Executive Officer
[email protected]
Solebury Trout
Michael Levitan
[email protected]