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

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

Author: Frank Vinluan

Xconomy Editor Frank Vinluan is a business journalist with experience covering technology and life sciences. Based in Raleigh, he was a staff writer at the Triangle Business Journal covering technology, biotechnology and energy before joining MedCityNews.com as North Carolina bureau chief. Prior to moving to North Carolina’s Research Triangle in 2007 he held business reporting positions at The Des Moines Register and The Seattle Times.