Scholar Rock Announces First Patient Dosed in Part A2 of DRAGON Phase 1 Proof-of-Concept Trial of SRK-181 to Overcome Primary Resistance to Anti-PD-(L)1 Therapy

Sept. 9, 2020 11:30 UTC


- Patients with locally advanced or metastatic solid tumors are being enrolled and dosed with SRK-181 in combination with anti-PD-(L)1 therapy in Part A2 of the DRAGON Phase 1 clinical trial

- An update on Part A dose escalation is expected in the fourth quarter of 2020; Part B efficacy and safety data from the trial anticipated starting in 2021


CAMBRIDGE, Mass.--(BUSINESS WIRE)--Scholar Rock (NASDAQ: SRRK), a clinical-stage biopharmaceutical company focused on the treatment of serious diseases in which protein growth factors play a fundamental role, today announced that the first patient has been dosed with SRK-181 in combination with anti-PD-(L)1 therapy in Part A2 of the DRAGON Phase 1 proof-of-concept trial. Part A1 of the DRAGON trial has successfully progressed dose escalation of SRK-181 monotherapy through 800 mg and continues to advance dose escalation. Part A1 and Part A2 are being conducted in a parallel but staggered fashion and will each evaluate doses up to 2400 mg. SRK-181 is a potent and highly selective inhibitor of latent TGFβ1 activation and is being developed to increase responses to immunotherapy by overcoming primary resistance to anti-PD-1 or anti-PD-L1 antibody therapy.

“We are encouraged by the dose escalation progress-to-date in Part A1 of the DRAGON trial, which has enabled us to begin the evaluation of SRK-181 in combination with anti-PD-(L)1 therapy,” said Yung Chyung, M.D., Chief Medical Officer of Scholar Rock. “While checkpoint inhibitor therapies have become standard of care for a large number of cancer patients, there is still significant unmet need as many patients demonstrate resistance to this therapeutic class. It is our belief that SRK-181 could help overcome this immune exclusion and has the potential to increase the therapeutic benefit of this class of drugs.”

The DRAGON Phase 1 open-label, dose escalation and dose expansion clinical trial consists of two parts to evaluate the efficacy, safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of SRK-181 in adult patients with locally advanced or metastatic solid tumors enrolled across multiple sites in the U.S. The Part A dose escalation portion of the trial is evaluating SRK-181 as both a single agent (Part A1) and in combination with approved anti-PD-(L)1 therapy (Part A2). The Part B dose expansion portion of the trial is expected to initiate in the first quarter of 2021 and will evaluate SRK-181 in combination with approved anti-PD-(L)1 therapy in multiple tumor-specific cohorts, including urothelial carcinoma, cutaneous melanoma, non-small cell lung cancer, and other solid tumors. As is the case in Part A2, Part B of the trial will enroll patients with locally advanced or metastatic solid tumors who had a lack of response to anti-PD-(L)1 therapy. These patients will be treated with SRK-181 in combination with anti-PD-(L)1 therapy to evaluate if they are able to achieve an anti-tumor response. Intravenous (IV) SRK-181 is administered every 3 weeks (Q3W) and additional dosing regimens may be explored. An update on Part A dose escalation is expected in the fourth quarter of 2020 and efficacy and safety data from Part B of the trial is anticipated starting in 2021.

About SRK-181

SRK-181 is a potent and highly selective inhibitor of TGFβ1 activation and is an investigational product candidate being developed to overcome primary resistance to checkpoint inhibitor therapy, such as anti-PD-(L)1 antibodies. TGFβ1 is the predominant TGFβ isoform expressed in many human tumors, particularly for those tumors where checkpoint therapies are currently approved. Based on analyses of human tumors that are resistant to anti-PD-(L)1 therapy, data suggests TGFβ1 is a key contributor to excluding immune cell entry into the tumor microenvironment, thereby preventing normal immune function. Scholar Rock believes SRK-181 has the potential to overcome this immune cell exclusion and induce tumor regression when administered in combination with anti-PD-(L)1 therapy. By specifically targeting the latent TGFβ1 isoform, Scholar Rock hypothesizes that SRK-181 can increase the therapeutic window by potentially avoiding toxicities associated with non-selective TGFβ inhibition. A Phase 1 proof-of-concept clinical trial in patients with locally advanced or metastatic solid tumors is ongoing. The effectiveness and safety of SRK-181 have not been established and SRK-181 has not been approved for any use by the FDA or any other regulatory agency.

About Scholar Rock

Scholar Rock is a clinical-stage biopharmaceutical company focused on the discovery and development of innovative medicines for the treatment of serious diseases in which signaling by protein growth factors plays a fundamental role. Scholar Rock is creating a pipeline of novel product candidates with the potential to transform the lives of patients suffering from a wide range of serious diseases, including neuromuscular disorders, cancer, fibrosis and anemia. Scholar Rock’s approach to targeting the molecular mechanisms of growth factor activation enabled it to develop a proprietary platform for the discovery and development of monoclonal antibodies that locally and selectively target these signaling proteins at the cellular level. By developing product candidates that act in the disease microenvironment, the Company intends to avoid the historical challenges associated with inhibiting growth factors for therapeutic effect. Scholar Rock believes its focus on biologically validated growth factors may facilitate a more efficient development path. For more information, please visit or follow Scholar Rock on Twitter (@ScholarRock) and LinkedIn (

Scholar Rock® is a registered trademark of Scholar Rock, Inc.

Forward-Looking Statements

This press release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding Scholar Rock’s future expectations, plans and prospects, including without limitation, Scholar Rock’s expectations regarding its growth, strategy, progress and timing of its clinical trials for SRK-181, the ability of any product candidate to perform in humans in a manner consistent with nonclinical, preclinical or previous clinical study data, and the potential of any product candidate or its proprietary platform. The use of words such as “may,” “might,” “will,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “project,” “intend,” “future,” “potential,” or “continue,” and other similar expressions are intended to identify such forward-looking statements. All such forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include Scholar Rock’s ability to provide the financial support, resources and expertise necessary to identify and develop product candidates on the expected timeline, the data generated from Scholar Rock’s nonclinical and preclinical studies and clinical trials, competition from third parties that are developing products for similar uses, Scholar Rock’s ability to obtain, maintain and protect its intellectual property, the success of Scholar Rock’s current and potential future collaborations, including its collaboration with Gilead, Scholar Rock’s dependence on third parties for development and manufacture of product candidates including to supply any clinical trials, Scholar Rock’s ability to manage expenses and to obtain additional funding when needed to support its business activities and establish and maintain strategic business alliances and new business initiatives, and the impacts of public health pandemics such as COVID-19 on business operations and expectations, as well as those risks more fully discussed in the section entitled "Risk Factors" in Scholar Rock’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2020, as well as discussions of potential risks, uncertainties, and other important factors in Scholar Rock’s subsequent filings with the Securities and Exchange Commission. Any forward-looking statements represent Scholar Rock’s views only as of today and should not be relied upon as representing its views as of any subsequent date. All information in this press release is as of the date of the release, and Scholar Rock undertakes no duty to update this information unless required by law.


Scholar Rock Contact:
Catherine Hu

Media Contact:
The Yates Network
Kathryn Morris


Source: Scholar Rock, Inc.

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