Asher Biotherapeutics is not the only biotech looking to improve upon the first generation of cytokine immunotherapies hampered by limited efficacy, tolerability and safety issues, but investors have taken note of the selectivity of the startup's cis-targeting platform and are confident enough to dole out $108 million.
That series B figure, at an oversubscribed amount, is the same amount hauled in by Synthekine, another company attempting to rewrite the cytokine landscape with an interleukin-2 (IL-2) approach, in June. The two companies have both received cash confidence from Janus Henderson and RA Capital Management.
Asher's series B also included lead investor Wellington Management and new backers Logos Capital, Marshall Wace and Alexandria Venture Investments in addition to Third Rock Ventures and multiple other original backers.
The proceeds will go toward Asher Bio's three main programs, including lead asset AB248. That lead drug is a cis-targeted IL-2 immunotherapy that activates CD8 effector T cells, which are critical to immune defense against intracellular viruses and bacteria and serve a role in surveilling tumors, while not activating regulatory T cells and natural killer cells.
Asher expects to file for trial approval and enter the clinic for AB248 in the third quarter of 2022, said Craig Gibbs, Ph.D., Asher CEO, in an interview with Fierce Biotech.
Asher will test AB248 in patients with solid tumors. The drug has a level of specificity 1,000-to-10,000 fold higher than traditional cytokine immunotherapies, Gibbs said. Cytokines interact with receptors on multiple cell types, leading to unwanted impacts on many different cell types, whereas Asher's AB248 is able to selectively engage two receptors on the same cell.
A toxicity study completed this summer "significantly de-risks the program and shows that we have a very clear therapeutic index that hasn't been seen before with previous IL-2 therapies, so that gave us a lot of confidence that we could be more aggressive about developing AB248," Gibbs said.
Early pharmacodynamic signals should arrive in early 2023, and a big readout in early 2024 would hopefully show "clinical proof of concept in terms of seeing objective anti-tumor responses in a good number of patients," Gibbs said.
Beyond AB248, Asher will use the series B proceeds to bankroll other preclinical programs, including a CD8+ T‑cell cis-targeted STAT3 cytokine and a CAR-T cis-targeted IL-2. Both assets have demonstrated preclinical proof-of-concept, the company said. Asher is in the preclinical stages for opportunities targeting infectious diseases, Gibbs said.
Gibbs said Asher would ideally advance its lead programs "as far as we can ourselves," but won't preclude collaboration opportunities, such as combination therapies and regional partnerships. Asher could look to partner on programs outside its leadership team's core expertise of immuno-oncology and oncology, Gibbs said.
The CEO was previously chief business officer of Forty Seven, a CD47 antibody that Gilead ponied up $4.9 billion to acquire in March 2020. Prior to Forty Seven, Gibbs spent 21 years at Gilead, leading up to vice president of commercial strategy.
Gibbs's leadership team includes Chief Scientific Officer, Ivana Djuretic, Ph.D., Chief Technology Officer Andy Yeung, Ph.D., and Chief Operating Officer Kyle Elrod. Djuretic and Yeung co-founded Asher in 2019 after leaving Pfizer, where Djuretic was head of cytokine biology in the Big Pharma's cancer immunology discovery unit.
The co-founders wanted to restore joy and happiness in patients, hence the biotech's name, Gibbs said. Asher means happy or blessed in Yiddish, he said.