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Context Therapeutics Signs Strategic Research Collaborations for Apristor® (onapristone extended release) With Key Academic Leaders in the Progesterone Receptor (PR) and Breast Cancer Fields

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  • Apristor1 is entering a phase 2 clinical
    trial for PR positive metastatic breast cancer in early 2019
  • Apristor has demonstrated clinical efficacy in three metastatic
    breast cancer studies with 140 patients

Context Therapeutics, a clinical stage biopharmaceutical company
dedicated to the treatment of hormone driven cancers, today announces it
has signed multiple research collaborations to further understand the
role of progesterone receptor (PR) signaling and its blockade to
overcome resistance mechanisms underlying metastatic breast cancer
(mBCa). These collaborations are with key leaders in the progesterone
and breast cancer fields and include Dr. Carol Lange, PhD at University
of Minnesota and Dr. Suzanne Fuqua, PhD at Baylor College of Medicine,
both of whom also serve as Scientific Advisory Board members at Context.
Additional academic collaborations include the laboratories of Dr. Sarat
Chandarlapaty, MD, PhD at Memorial Sloan Kettering Cancer Center, Dr.
Geoffrey Greene, PhD at University of Chicago and Dr. Seema Khan, MD at
Northwestern University.

Breast cancer is the most commonly diagnosed cancer and the second
leading cause of cancer related death in women. Approximately 155,0002
women in the United States have mBCa and the median overall survival in
this setting is three years3. Three primary mBCa subtypes
exist: hormone receptor positive (HR+) that express estrogen receptor
(ER) and/or progesterone receptor (70-80% of patients)4;
human epidermal growth factor receptor 2 (HER2)-positive (10-15%)5;
and triple negative (10-17%)6. For patients with HR+ mBCa,
antiestrogen blockade is the backbone therapy across first (1L) and
second (2L) treatment lines. Unfortunately, current treatments in 1L and
2L are not curative and only delay progression to chemotherapy.
Therefore, there is a critical need for targeting additional mechanisms
alone or in combination with antiestrogens to enhance therapeutic
response and provide these patients with better outcomes.

Progesterone, a major mitogen in the adult human mammary epithelium, is
also a key driver of breast cancer cell proliferation. Context
Therapeutics is pursuing an innovative approach to the treatment of
advanced breast cancer by blocking both ER and PR, the primary drivers
of HR+ mBCa disease progression, through the combination of Apristor, a
unique PR full antagonist7, with the antiestrogen Falsodex®8
(fulvestrant). Apristor has established efficacy as an antitumor agent
in the clinical setting, as well as in multiple preclinical breast
cancer models and exhibits additive/synergistic effects with
antiestrogens, providing a strong rationale for this combination.

A Phase 2 clinical trial in advanced breast cancer patients with
Apristor in combination with Fulvestrant in 2L therapy is planned for
early 2019. The randomized, double-blind, placebo-controlled study will
be powered to show efficacy with Apristor added to the standard of care
(Fulvestrant) versus the standard of care alone.

The research at the above academic centers will focus on expanding the
understanding of mechanisms underlying resistance in breast cancer and
novel therapeutic combinations that could be useful in treating advanced
breast cancer with Apristor.

Under the terms of the collaborations, Context will provide Apristor and
collaborate with the research groups. While it is well known that
Apristor is a unique PR antagonist that inhibits both ligand-dependent
and growth factor induced PR activities, access to the drug for basic
research purposes has been historically limited. Context is providing
the compound to key interested academic partners with the aim of
advancing breast cancer research and understanding the role of PR
signaling in mammary tumors and other indications.

About Progesterone Receptor Antagonism

Context is developing Apristor, a first-in-class orally-bioavailable
progesterone receptor (PR) antagonist for PR+ breast cancer. Up to 60%
of breast cancer patients are believed to be PR+9. Apristor
is an investigational medicine that has completed Phase 1 development
and will be further evaluated in an upcoming randomized,
placebo-controlled Phase 2 trial in second-line metastatic breast cancer
patients who are PR+ and have failed prior antiestrogen therapeutic with
or without the addition of a Cdk4/6 inhibitor.

About Context Therapeutics

Context Therapeutics is a clinical-stage biopharmaceutical company
dedicated to creating new medicines to treat hormone-responsive cancers.
Context's lead program is Apristor (onapristone extended release), an
investigational Phase 2 drug that is being developed for progesterone
receptor positive (PR+) metastatic breast cancers. In addition, Context
is advancing a discovery-stage program targeting Sigma1. For more
information on Context, visit www.contexttherapeutics.com.

1 When discussing historical trials, references to Apristor
include both onapristone immediate release and onapristone extended
release; all current and future trials will consist solely of
onapristone extended release.

2 Cancer Epidemiol Biomarkers Prev. 2017 26(6): 809–815

3 Breast. 2012; Vol 21, Issue 3, pages 242–252

4,5,6 American Cancer Society. Breast Cancer Facts & Figures
2017-2018. Atlanta: American Cancer Society, Inc. 2017

7 Steroid Biochem. Molec. Biol. Vol. 53, No. 1-6, pp.
449-458, 1995; Journal of Hematology & Oncology (2017) 10:89; Molecular
Cellular Biology, Mar. 1998, p. 1369–1378; Oncogene (2014), 1–10

8 Falsodex® is a registered trademark of the Astra
Zeneca group of companies

9 www.breastcancer.org

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