Pharma, BioPharma

Asher Bio’s encouraging early data against rival cancer drug sparks $108M financing

Five months after raising $55 million to back a new technology and a promising lead cancer immunotherapy, Asher Biotherapeutics has reeled in $108 million more. CEO Craig Gibbs said investors were enticed by encouraging new data suggesting Asher Bio’s lead program is superior to a competitor's.

 

Asher Biotherapeutics emerged from stealth in the spring with a novel technology, a lead cancer immunotherapy candidate, and the cash to reach the clinic. Clinical trials are coming, but the startup now has additional preclinical data showing its drug bests a rival immunotherapy candidate head to head, and those animal results have persuaded investors to pump an additional $108 million into the company.

Wellington Management Company led the Series B round of funding announced Wednesday.

The research of South San Francisco-based Asher Bio focuses on interleukin-2 (IL-2), a signaling protein in the body that sparks an immune response. Engineered IL-2 therapies have been available for years, but their broad effect beyond the intended target cells, as well as their toxicity, limit their use. Asher aims to overcome those problems with technology that activates the IL-2 pathway in a more targeted manner.

Asher’s drugs achieve a targeted effect because they’re designed to hit two receptors on the same target cell. The company calls its approach cis-targeting. Lead Asher Bio drug candidate AB248 is a fusion protein engineered to selectively activate the IL-2 pathway on a specific type of immune cell called a CD8+ T cell. When Asher Bio closed its $55 million Series A financing in March, the company had mouse data showing that the immunotherapy cleared tumors.

In the months since, Asher Bio has generated additional data that have driven investor interest, CEO Craig Gibbs said in an email. The company now has results comparing AB248 against another IL-2 drug showing that a single dose of Asher’s fusion protein was better at eliminating most of the tumors in three different mouse tumor models. Those effects were achieved without weight loss in the mice, which would be a sign of adverse effects. He added that preliminary toxicology data in monkey studies indicate a favorable therapeutic index for the therapy.

Gibbs did not identify the immunotherapy that Asher’s drug was compared to, other than to say it was a “leading clinical-stage IL-2 therapeutic candidate.” That description fits THOR-707, the lead IL-2 therapy from Synthorx and the centerpiece of that biotech’s $2.5 billion acquisition by Sanofi last year. At the annual meeting of the American Association for Cancer Research in April, Sanofi reported preliminary Phase 1 data indicating anti-tumor activity for THOR-707, by itself and in combination with a type of immunotherapy called a checkpoint inhibitor. Xilio Therapetics is also developing an IL-2 drug, but the Waltham, Massachusetts-based biotech is not yet reached the clinic.

So far, Asher has not published any of its research. Gibbs said the company plans to present data at medical meetings this fall, followed by publication of those data in peer-reviewed journals. Asher has more IL-2 drugs in the pipeline. Gibbs said that the company has demonstrated preclinical proof of concept for two additional programs. The new Series B financing will support the company’s lead program through Phase 2 development; an investigational new drug application is expected in the third quarter of next year. The cash will also enable the company to advance a second program through the preclinical research leading up to clinical testing.

Other new Asher Bio investors that joined the latest financing include RA Capital Management, Janus Henderson Investors, Logos Capital, Marshall Wace and Alexandria Venture Investments. Earlier investors Third Rock Ventures, Invus, Boxer Capital of Tavistock Group, Mission BioCapital, also participated in the financing. Some of the Series B investors are firms that put their money into both private companies and public companies. Drawing large sums of cash from such “crossover” investors can be viewed as a sign that a company is preparing for an IPO.

Gibbs would not say whether the round was a crossover round. He said Asher’s goal was to have a group of leading life science investors, a mix of those with experience in the private and public markets, to support the company’s lead program and allow the firm to exploit the full potential of the cis-targeting platform.

“We feel that this puts Asher Bio in the best position to have strong and diverse investors, so we have the expertise and capital around the table to pursue a range of opportunities for our future growth,” Gibbs said.

Photo by Asher Biotherapeutics

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