Asher Bio Closes $55 Million Series C Financing to Advance Lead Program into Phase 1b Clinical Trials

Asher Biotherapeutics, a biotechnology company developing precisely-targeted immunotherapies for cancer, autoimmune, and infectious diseases, today announced the closing of a Series C financing, which raised $55 million. The financing was led by RA Capital Management, and included new investors AstraZeneca (LSE/STO/Nasdaq: AZN) and Bristol Myers Squibb, along with existing investors Janus Henderson Investors, Third Rock Ventures, Wellington Management and Boxer Capital and other undisclosed institutional investors.

"We are delighted to have the continued support of RA Capital, and excited to add two top biopharmaceutical companies and experts in oncology to our investor syndicate," said Craig Gibbs, Ph.D., Chief Executive Officer of Asher Bio. "We are committed to delivering a new class of highly selective cis-targeted immunotherapies for cancer, which are designed to activate only the desired immune cell type to potentially maximize efficacy and limit off-target toxicities. We are pleased to have investors with deep and hands-on expertise in the cytokine space recognizing our early clinical data and our differentiated approach. This Series C financing generated robust demand and positions us well to continue AB248's clinical development to generate tumor response data from monotherapy expansion cohorts, as well as data from dose escalation and expansion in combination with a PD-1 checkpoint inhibitor."

Asher Bio plans to use the proceeds from this financing to advance the clinical development of its lead program, AB248, a novel CD8+ T cell selective IL-2, generated by fusing a reduced potency IL-2 mutein to an anti-CD8? antibody. AB248 is currently being investigated in a Phase 1a/1b study, which is evaluating AB248 as a monotherapy and in combination with KEYTRUDA^® (pembrolizumab), in patients with recurrent locally advanced or metastatic solid tumors, including melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN), previously treated with a PD1 or PD-L1 checkpoint inhibitor.

AB248 was specifically engineered to selectively and potently activate CD8+ T-cells, while avoiding natural killer (NK) cells, which can act as a pharmacological sink and contribute to toxicity, and regulatory T (Treg) cells, which are immunosuppressive. Initial pharmacokinetic and pharmacodynamic data from the ongoing Phase 1a/1b clinical trial support AB248's proof of mechanism and activity with a highly differentiated clinical profile. Early data shows potent and selective CD8+ T cell activation without substantial changes to Treg and NK cell numbers and initial evidence of anti-tumor activity, with a generally well-tolerated safety profile.

"Asher's groundbreaking cis-targeting platform offers a highly differentiated approach to immunotherapy, with the potential to overcome the limitations of other immune-based treatments by maximizing efficacy and limiting off-target toxicities," said Jake Simson, RA Capital Management. "The company has produced promising preclinical and early clinical data to date and we are excited to continue to support Asher as they further advance their lead program in the clinic."

KEYTRUDA^® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About Asher Bio

Asher Bio is a biotechnology company developing therapies to precisely engage specific immune cells to fight cancer, chronic viral infection and autoimmune disease. We utilize our proprietary cis-targeting platform to develop therapies engineered to overcome limitations of other immune-based treatments by selectively activating specific immune cell types with validated disease fighting functionality. Our candidates feature an antibody connected to a modified immunomodulatory protein, such as a cytokine. Our candidate design is intended to enable our candidates to selectively activate the desired immune cells and not other cells that contribute to toxicity or immune suppression. Our lead program AB248, an investigational IL-2 molecule specifically targeted to CD8+ effector T cells, is currently in Phase 1 trials for oncology. Our broader portfolio includes AB821, a CD8-targeted IL-21 immunotherapy, and early-stage programs targeting CAR-T cells, myeloid cells and CD4+ T cells. Asher Bio was founded by Ivana Djuretic and Andy Yeung with support from Third Rock Ventures and is located in South San Francisco. For more information, please visit www.asherbio.com and follow us on X (formerly Twitter) @AsherBio and on LinkedIn.