Cancer start-up will get $47m

Jounce to focus on immunotherapy; Third Rock has started 21 companies

Boston venture capital firm Third Rock Ventures is set to disclose Thursday that it is putting up $47 million to launch a cancer immunotherapy start-up in Cambridge.

The company will be called Jounce Therapeutics Inc., a name derived partly from a well-known physics term and partly from a synonym for jolt. It is meant to signal the dramatic change the company and its financial backers expect from their cancer-fighting approach.

Rather than targeting tumors directly, Jounce intends to develop drugs that can harness the immune system to seek out and attack cancerous cells, sometimes in combination with other medicines. Jounce hopes it’s an approach that can be used against many types of cancers.


“We’re taking a pretty broad approach, going after multiple mechanisms of action and molecular targets in this [cancer] space,” said Cary ­Pfeffer, the Third Rock partner who will serve as interim chief executive of Jounce until the company hires a permanent chief executive.

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Jounce’s launching is typical of Third Rock, which focuses exclusively on the biopharmaceutical field and prefers to start companies rather than simply invest in established operations. Since it was formed in 2007, Third Rock has given birth to 21 start-ups, including 15 in the Boston area.

For Jounce, which is setting up shop at 1030 Massachusetts Ave. outside Harvard Square, Third Rock has assembled a group of founding scientists who have been leaders in the field of immunobiology. They include James P. Allison, chairman of the department of immunology at the University of Texas MD Anderson Cancer Center. Allison’s research spurred clinical development of the melanoma treatment Yervoy, one of the first cancer immunotherapies.

Allison said the goal of Jounce will be to develop therapies to activate naturally occurring cells in the human body that can then recognize and attack cancer cells. Company scientists will also seek to understand why tumors aren’t recognized in some cases.

“We’re treating the immune system, not the tumor,” Allison said of the Jounce approach. “We can definitely look forward to a durable response when we do it this way.” Several other drug companies are also working in the area­ of cancer immunotherapies, including Merck & Co. and Bristol-Myers Squibb Co., but Pfeffer said he was betting on Jounce’s team.


The company is starting with just under 10 employees but expects its staff to grow to between 20 and 25 by the end of the year, Pfeffer said.

Robert Weisman can be reached at