Asher Biotherapeutics: $55 Million Raised To Develop Precisely-Targeted Immunotherapies

By Amit Chowdhry • Apr 17, 2024

Asher Biotherapeutics, a biotechnology company that is developing precisely targeted immunotherapies for cancer, autoimmune, and infectious diseases, announced the closing of a $55 million Series C funding round. This funding was led by RA Capital Management and included new investors AstraZeneca and Bristol Myers Squibb, along with existing investors Janus Henderson Investors, Third Rock Ventures, Wellington Management, Boxer Capital, and other undisclosed institutional investors.

Asher Bio plans to use the proceeds from this funding round 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-CD8β antibody.

AB248 is now 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 built to selectively and potently activate CD8+ T-cells, while avoiding natural killer (NK) cells, which could act as a pharmacological sink and contribute to toxicity, and regulatory T (Treg) cells, and are immunosuppressive. And the 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.

The early data showed potent and selective CD8+ T cell activation without substantial changes to Treg and NK cell numbers, initial evidence of anti-tumor activity, and a generally well-tolerated safety profile.


“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. 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.”

– Craig Gibbs, Ph.D., Chief Executive Officer of Asher Bio

“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. 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.”

– Jake Simson, RA Capital Management