Bolt Bio Bags $54M for Drugs that Turn the Heat Up on “Cold” Tumors

Xconomy San Francisco — 

In cancer lingo, “cold” tumors are cancers that the immune system doesn’t recognize or respond to, even when immune-stimulating drugs are given.

Bolt Biotherapeutics is developing drugs intended to turn cold tumors—the majority of cancers—“hot” so that other immunotherapies can work, and has raised $54 million to support its research. The Redwood City, CA, startup says its goal is to unleash the immune system in patients for whom a class of cancer immunotherapies, called checkpoint inhibitors, are ineffective. Bolt Bio says it is now working toward human tests of its lead drug.

Bolt Bio’s approach gives a one-two punch to cancer. The company’s therapies consist of a tumor-targeting antibody that homes in on tumors and is paired with an immune stimulant that turns cold tumors into hot ones. In preclinical testing, the company says that these immune-stimulating antibody conjugates eliminated tumors. The company has not yet said which cancers it aims to treat.

Bolt Bio was founded by Ed Engleman, a professor of pathology and medicine at Stanford Medicine. The company’s drug platform is based on technology licensed from Stanford University.

Pivotal bioVenture Partners led the Series B round of funding, and was joined by Nan Fung Life Sciences. Earlier investors Novo  Holdings and Vivo Capital also participated in the financing.

Photo by Flickr user Dierk Schaefer via a Creative Commons license