Bristol Myers Squibb has returned an experimental cancer immunotherapy to Agenus, ending an alliance that couldve been worth more than $1 billion to the Lexington, Massachusetts-based biotechnology company.In a regulatory filing Friday, Agenus revealed a licensing deal the two forged in 2021 was terminated by Bristol Myers as part of the pharmaceutical firms strategic realignment to its research and development efforts. That restructuring involves Agenus drug, codenamed AGEN1777, as well as other licensed products, and will result in the deals termination on Jan. 26.AGEN1777 is one of several drug candidates aimed at a protein called TIGIT. These drugs have been closely watched in recent years because of early results suggesting they may boost the effects of other cancer immunotherapies. Large companies such as Merck & Co., Roche, Gilead Sciences, GSK and Bristol Myers have all either advanced in-house programs or cut deals for TIGIT prospects.But later-stage results have been less clear. Roches TIGIT drug, tiragolumab, failed multiple late-stage trials, leading the company to discontinue a few additional tests. Mercks vibostolimab has struggled as well and, following a study setback in May, the company has appreciably pulled back its TIGIT work by stopping multiple studies, wrote Leerink Partners analyst Daina Graybosch in a research note last month.Though other key study results lay ahead most notably, a Phase 3 trial evaluating whether Roches drug helps people with lung cancer live longer the findings so far have left analysts skeptical of the class potential.The totality of evidence suggests TIGIT adds clinically relevant, but modest, benefit to commonly used cancer immunotherapies, Graybosch wrote.Bristol Myers is now reducing its investment in TIGIT as well. The company acquired AGEN1777 in 2021 by paying Agenus $200 million in cash. The drug has since advanced to mid-stage testing in a form of gastric cancer, and Agenus received $45 million in additional milestone payments. Bristol Myers was expected to report data from that trial this year.Those results havent yet been disclosed. Agenus said in its regulatory filing that the trial has generated significant safety data and shown indications of clinical activity. The company intends to either develop AGEN1777 on its own or find a new partner.Still, the deals termination leaves another $1 billion or so in downstream payouts unpaid, a financial blow to a company that in the last year has restructured and lost most of its share value. Agenus had about $53 million on hand at the end of the first quarter and cut a royalty financing deal to bolster its cash reserves.Bristol Myers, meanwhile, has been trimming its pipeline as part of a broader restructuring meant to save the company $1.5 billion by the end of next year. It intends to reinvest those savings towards higher growth opportunities, David Elkins, the companys chief financial officer, said on a conference call with analysts last month. The company doesnt have any other TIGIT drugs in clinical testing. '