Hummingbird Bioscience to Present Two Posters on HER3-Targeting Therapeutics at American Association for Cancer Research (AACR) Meeting 2023

Presentations highlight the robust tumor growth inhibition in preclinical models for its HER3-targeting programs HMBD-001 (HER3 mAb) and HMBD-501 (HER3 ADC)

HMBD-001 used as monotherapy or in combination with cetuximab effectively inhibits tumor growth in preclinical squamous cell carcinoma models

HMBD-501 shows superior preclinical efficacy and tolerability compared to other HER3 ADCs across a range of preclinical models,presenting a potentially best-in-class profile

SAN FRANCISCO,HOUSTON and SINGAPORE,March 15,2023 -- Hummingbird Bioscience,a data-driven precision biotherapeutics company discovering and developing transformative biologic medicines for hard-to-treat diseases,today announced two upcoming poster presentations at the American Association for Cancer Research (AACR) Meeting 2023 (April 14-19) in Orlando,Florida.

The company will present a poster describing the efficacy of HMBD-001,a clinical-stage anti-HER3 mAb currently in Phase 1a clinical trial (NCT05057013),across multiple preclinical models of squamous cell carcinomas and a poster demonstrating the efficacy and tolerability of HMBD-501,a next generation HER3-targeting antibody-drug conjugate (ADC),in preclinical solid tumor models.

The poster for HMBD-001 highlights that inhibition of HER3 has broad applicability in squamous cell carcinomas and this anti-tumor activity can be enhanced with concurrent inhibition of EGFR,with significant potential to improve patient outcomes. Robust tumor growth inhibition in various preclinical squamous cancer models,including lung,esophageal and head and neck,is observed with HMBD-001 when used as monotherapy and in combination with cetuximab. The HMBD-501 poster discusses the rational design of the HER3 ADC,its potentially best-in-class safety and tolerability profiles,and superior inhibition of tumor growth compared to other HER3 ADCs,across a range of preclinical cancer models.

"We are excited to be on the cusp of the new horizon of therapies for HER3-expressing cancers. At AACR,we will have the first publication of preclinical results for our potentially best-in-class HER3 ADC," said Jerome Boyd-Kirkup,Ph.D.,Chief Scientific Officer,Hummingbird Bioscience. "The potent anti-tumor activity we see from our clinical-stage HMBD-001 program is exciting and represents a broad treatment opportunity due to conserved sensitivity to HER3 and EGFR inhibition across multiple squamous carcinomas. We look forward to discussing the promising data for our novel HER3-targeting therapeutics with the oncology research community at AACR."

Session Category: Experimental and Molecular Therapeutics

Session Title: Antibody Technologies

Session Date and Time: Monday Apr 17,2023 1:30 PM - 5:00 PM ET

Location: Poster Section 13

HMBD-001 Presentation

Title: Anti-HER3 antibody,HMBD-001,in combination with an EGFR inhibitor effectively inhibits tumor growth in biomarker-selected preclinical models of squamous cell carcinomas

Poster Board Number: 27

Published Abstract Number: 2659

HMBD-501 Presentation

Title: HMBD-501 - a novel Fc engineered,exatecan-based next generation HER3 targeting antibody drug conjugate shows robust efficacy and tolerability in preclinical solid tumor models

Poster Board Number: 28

Published Abstract Number: 2660

About Hummingbird Bioscience

Hummingbird Bioscience is a data-driven precision biotherapeutics company discovering and developing transformative biologic medicines for hard-to-treat diseases. The Hummingbird Bioscience model combines computational and systems biology with wet lab drug discovery in a multi-disciplinary,collaborative environment spanning initial discovery through clinical development. We harness this integrated approach across target identification and patient selection,enabling our team to increase the efficiency of translating novel scientific insights while reducing the inherent risk in drug discovery and development. We are currently developing two clinical-stage assets: HMBD-001,a humanized anti-HER3 monoclonal antibody targeting a novel epitope on HER3,and HMBD-002,a humanized anti-VISTA IgG4 monoclonal antibody. Both programs are currently in Phase 1 studies. At Hummingbird Bioscience,our commitment to rigorous science,teamwork and intellectual integrity underpins our passion to accelerate the journey of new drugs from concept to clinic.

For more information,please visitwww.hummingbirdbioscience.com,and follow Hummingbird Bioscience onLinkedIn,Twitter,andYouTube.

About HMBD-001

HMBD-001 is a clinical-stage IgG1 antibody designed to target HER3. Discovered using Hummingbird Bioscience's proprietary Rational Antibody Discovery (RAD) platform,HMBD-001 is now in development for the treatment of multiple solid tumors. We believe HMBD-001 is the only anti-HER3 antibody in development that has the potential to fully block both ligand-dependent and -independent HER3 activation and oncogenic signaling,by targeting a key epitope located at the interface where HER3 forms heterodimers with HER2 or EGFR. In preclinical models evaluating HMBD-001,the company has observed superior affinity and more potent tumor growth inhibition compared to existing anti-HER3 antibodies. Near-term development plans for HMBD-001 focus on a few priority,high-value indications with strong scientific rationale and supporting preclinical data,which includes HER3-driven cancers.

About HMBD-501

HMBD-501 is a differentiated,potentially best-in-class HER3 ADC with an enhanced efficacy and safety profile over prior generation ADCs. HMBD-501 combines a best-in-class antibody generated by our antibody discovery and engineering platform and state-of-the-art ADC technologies,overcoming issues with prior generation ADCs that do not target optimal epitopes and lack optimal homogeneity,hydrophilicity and stability. HMBD-501 has picomolar binding affinity,an engineered Fc that potentially enhances the safety profile,and a clinically-validated exatecan payload. HMBD-501 shows superior tumor growth inhibition across a range of preclinical solid tumor models and preclinical tolerability. With key proprietary technologies enabling a differentiated molecule,we believe HMBD-501 is poised to become a best-in-class HER3 ADC.

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