Gilead Sciences and Tango Therapeutics hit the dance floor two years ago, with $50 million changing hands in a deal covering up to five immuno-oncology targets. Now, Gilead is ponying up another $125 million upfront, as well making a $20 million equity investment, to expand that deal to include up to 15 targets.
The agreement centers on Tango’s work in synthetic lethality, the interaction between two genes that causes cell death when both are inactivated. In cancer cells, one of these genes is inactivated by a mutation; the other will be inactivated by a drug. Synthetic lethality is a way to treat cancers driven by tumor evasion genes—which keep the immune system from killing tumors—and lost tumor suppressor genes, which have long evaded drug developers.
“Since we signed the original agreement two years ago, we have been very pleased with the productivity of the collaboration and with the quality of scientific discovery that has come from this partnership,” William Lee, Ph.D., executive vice president of research at Gilead, said in a statement Monday. “We are looking forward to working with Tango to run additional cancer context dependent screens to identify a broader set of targets based on our immuno-oncology strategy.”
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The original deal had Gilead on the hook for $1.7 billion in preclinical fees and development, regulatory and commercial milestones if all five programs hit their goals. Now, the company’s promising as much as $410 million for each program it chooses to take forward; if it opts into all 15, that’s an eye-watering $6.15 billion. Gilead will have the next seven years to figure out which programs it wants to pick up.
Tango has carried out, and will continue to handle, discovery work on the targets, and Gilead may pull the trigger on the worldwide rights to any of the targets. Gilead could also hand over option extension fees for Tango to take care of early clinical development, too.
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The partnership does not include Tango’s lead programs, one of which is expected to start IND-enabling studies in 2021. The company picked up $60 million in April to advance that program as well as to conduct earlier-stage work.
“Our lead program is a drug target that is a synthetic lethal pair with a commonly lost gene in cancers,” Weber said.
“We’re making great progress on that program and hope to have a clinical development candidate from that early next year,” Tango CEO Barbara Weber, M.D., said at the series B close.
The company has four drug discovery programs following behind, targeting synthetic lethality in different patient groups. It believes combining its synthetic lethality drugs with other cancer treatments can close the gap between partial responses and complete responses.
Beyond its own pipeline and the Gilead partnership, Tango expects its discovery platform to turn up more targets than it can go after on its own. It will “absolutely” continue striking deals, Weber said.