Vir Biotechnology Announces Encouraging Safety and Efficacy Data in Ongoing Dose Escalation Trials for Dual Masked T-Cell Engagers VIR-5818 in Solid Tumors and VIR-5500 in mCRPC
– Compelling early clinical response signals for VIR-5818 and VIR-5500 in heavily pretreated patients with various solid tumors
○ VIR-5818: In patients receiving doses ≥400 µg/kg, tumor shrinkage observed in
○ VIR-5500: PSA declines in
– Promising safety profile with MTD not yet reached for VIR-5818 or VIR-5500 and no dose-limiting cytokine release syndrome (CRS) observed; no CRS greater than grade 2 reported
– Initial clinical data demonstrate PRO-XTEN™ masking technology may lead to minimal systemic unmasking and unlocks expanded therapeutic index
– Investor conference call January 8, 2025, at 5:00 a.m. PT / 8:00 a.m. ET, available on https://investors.vir.bio
“Overcoming the toxicity-driven limitations of traditional T-cell engagers could address an important unmet medical need in cancer care,” said Marianne De Backer, M.Sc., Ph.D., MBA, Chief Executive Officer, Vir Biotechnology. “Preliminary safety and efficacy data for our dual-masked T-cell engagers VIR-5818 and VIR-5500 are compelling, and we will continue dose escalation with an opportunity to expand the therapeutic window. We are encouraged that our candidates may enable efficacious and well-tolerated treatment regimens, potentially improving outcomes for people living with a range of solid tumors.”
VIR-5818: PRO-XTEN™ Initial Proof-of-Concept and Potential First-in-Class HER2 Immunotherapy
Despite availability of HER2-targeting therapies, there remains a significant unmet need for treatments with novel mechanisms of action to improve tolerability and extend survival. Currently, no HER2-directed immunotherapies are approved for solid tumors. The preliminary safety and efficacy data of VIR-5818 support the tumor-specific activation of PRO-XTEN™ dual-masked TCEs and the potential of this technology to broaden the therapeutic index of TCEs.
VIR-5818 is being evaluated in a Phase 1 clinical trial (NCT05356741) designed to study its safety and pharmacokinetics alone, and in combination with pembrolizumab, in participants with a variety of HER2-expressing cancers, including breast and colorectal cancer (CRC). The study has enrolled 79 heterogeneous and heavily pretreated participants in monotherapy cohorts.
Early efficacy data indicate that
Preliminary safety data demonstrate that VIR-5818 is generally well-tolerated, with minimal grade 1 or 2 CRS (
VIR-5500: First Dual-Masked PSMA-Targeting TCE
Prostate cancer is the second most diagnosed cancer in men1. Despite advancements, there is still a significant unmet need for efficacious, well-tolerated treatments that can extend survival and improve quality of life.
VIR-5500 is being evaluated in a Phase 1 clinical trial (NCT05997615) designed to assess its safety, pharmacokinetics, and preliminary efficacy in participants with mCRPC. The study has enrolled 18 participants with significant disease burden who have received 3 to 6 prior lines of therapy.
Early efficacy data show encouraging signs of prostate-specific antigen (PSA) responses, and PSA reductions were observed in
Preliminary data show a promising safety profile, with no dose-limiting toxicities observed up to 1000 µg/kg without prophylactic corticosteroids. Safety findings showed minimal grade 1 or 2 CRS (
About VIR-5818, VIR-5500, VIR-5525
VIR-5818, VIR-5500, VIR-5525 are investigational, clinical candidates currently being evaluated for the treatment of solid tumors. These assets leverage the PRO-XTEN™ masking technology with three different T-cell engagers (TCEs) targeting HER2, PSMA, and EGFR, respectively.
TCEs are powerful anti-tumor agents that can direct the immune system, specifically T-cells, to destroy cancer cells. The PRO-XTEN™ masking technology is designed to keep the TCEs inactive (or masked) until they reach the tumor microenvironment, where tumor-specific proteases cleave off the mask and activate the TCEs, leading to killing of cancer cells. By driving the activity exclusively to the tumor microenvironment, we aim to circumvent the traditionally high toxicity associated with TCEs and increase their efficacy and tolerability. Additionally, the mask is designed to help drug candidates stay in the bloodstream longer in their inactive form, allowing them to better reach the site of action and potentially allowing less frequent dosing regimens for patients and clinicians.
References:
1 Ferlay J, Ervik M, Lam F, Laversanne M, Colombet M, Mery L, Piñeros M, Znaor A, Soerjomataram I, Bray F (2024). Global Cancer Observatory: Cancer Today.
About Vir Biotechnology, Inc.
Vir Biotechnology, Inc. is a clinical-stage biopharmaceutical company focused on powering the immune system to transform lives by discovering and developing medicines for serious infectious diseases and cancer. Its clinical-stage portfolio includes infectious disease programs for chronic hepatitis delta and chronic hepatitis B infections and multiple dual-masked T-cell engagers across validated targets in solid tumor indications. Vir Biotechnology also has a preclinical portfolio of programs across a range of infectious diseases and oncologic malignancies. Vir Biotechnology routinely posts information that may be important to investors on its website.
Vir Biotechnology has exclusive rights to the PRO-XTEN™ masking platform for oncology and infectious disease. PRO-XTEN™ is a trademark of Amunix Pharmaceuticals, Inc., a Sanofi company.
Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “should,” “could,” “may,” “might,” “will,” “plan,” “potential,” “aim,” “expect,” “anticipate,” “promising” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements regarding: the therapeutic potential of Vir Biotechnology’s oncology solid tumor portfolio, preclinical pipeline and PRO-XTEN™ masked TCE platform, including the capability to overcome toxicity-driven limitations of traditional TCEs and expand therapeutic index with efficacious and well-tolerated TCE treatment regimens, which could improve outcomes for people living with a range of solid tumors; Vir Biotechnology’s clinical development plans and expectations for its TCE assets, including with respect to potential dosing regimens; and any assumptions underlying any of the foregoing. Many factors may cause differences between current expectations and actual results, including, without limitation: unexpected safety or efficacy data or results observed during clinical studies or in data readouts, including the occurrence of adverse safety events; risks of unexpected costs, delays or other unexpected hurdles; the timing and amount of Vir Biotechnology’s actual operating expenses, as determined in accordance with
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Arran Attridge
Senior Vice President, Corporate Communications
aattridge@vir.bio
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Richard Lepke
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rlepke@vir.bio
Source: Vir Biotechnology, Inc.