(Updated - July 21, 2020 8:32 AM EDT)

Gilead Sciences, Inc. (Nasdaq: GILD) today announced that it will invest $300 million to acquire a 49.9 percent equity interest in Tizona Therapeutics, Inc., a privately held company developing first-in-class cancer immunotherapies. Gilead will also receive an exclusive option to acquire the remainder of Tizona for up to an additional $1.25 billion, including an option exercise fee and potential future milestone payments.

Gilead can exercise its option to acquire the remainder of Tizona following the readout of a Phase 1b study of Tizona’s investigational antibody, TTX-080, or earlier if Gilead decides to do so. TTX-080, discovered by Tizona, is a potential first-in-class medicine that targets HLA-G, a novel and emerging immune checkpoint expressed across multiple tumor types. The expression pattern of HLA-G often appears distinct from that of PD-(L)1, suggesting potential utility to address tumors that do not respond to current anti-PD-(L)1 treatments and to deepen responses in tumors that are sensitive to anti-PD-(L)1 therapies.

The U.S. Food and Drug Administration has cleared Tizona’s Investigational New Drug (IND) application for TTX-080, and in the third quarter of this year, Tizona plans to initiate a Phase 1 clinical trial evaluating TTX-080 both as a monotherapy and in combination with other agents in patients with advanced cancers.

“Tizona is pursuing first-in-class cancer immunotherapies that could make an important difference in oncology by helping patients who don’t respond to current checkpoint inhibitors,” said Daniel O’Day, Chairman and Chief Executive Officer, Gilead Sciences. “This agreement with Tizona adds to the significant progress we’ve made in the first half of this year in building out a strong and diverse immuno-oncology pipeline. We now have multiple opportunities to develop novel therapies that will improve the treatment of cancer.”

“Gilead’s support will enable Tizona to accelerate and broaden our TTX-080 clinical program while also enabling us to rapidly advance our rich, first-in-class preclinical portfolio and target validation efforts,” said Scott Clarke, Chief Executive Officer, Tizona. “Our mission is dedicated to translating novel scientific insights into first-in-class immunotherapies and Gilead is a partner that shares our passion for science and delivering breakthrough innovation to people with cancer.”

Terms of the Agreement

Under the terms of the agreement, Tizona equity holders will receive $300 million upon closing. Gilead will obtain a 49.9 percent equity stake and an exclusive option to purchase the remaining equity exercisable following the completion of Phase 1b studies for TTX-080, or earlier if Gilead chooses. Tizona equity holders will be eligible to receive up to $1.25 billion in an option exercise fee and potential future milestone payments. Gilead will also provide funding to support Tizona’s ongoing research and development to advance its novel pipeline.

The transaction is expected to close in the third quarter of this year and is subject to antitrust clearance under the Hart-Scott-Rodino Antitrust Improvements Act and other customary closing conditions.

Gilead will have the right to appoint two individuals to Tizona’s Board of Directors upon closing of the transaction.

Tizona will spin off TTX-030, the company’s investigational, first-in-class anti-CD39 antibody partnered with AbbVie, into a separate entity prior to closing of this transaction. TTX-030 is not subject to this agreement.

TTX-080 is investigational and not approved anywhere globally. Its efficacy and safety have not been established.

Cowen is acting as financial advisor and Ropes & Gray is acting as legal counsel to Gilead. Latham & Watkins is acting as legal counsel and Squire Patton Boggs is acting as IP counsel to Tizona.