Antibody drug conjugates continue to be a robust area for research and dealmaking, and Eli Lilly’s latest move in this space is the acquisition of CrossBridge Bio, a preclinical startup with technology and a lead program that could bring patients more powerful cancer treatments.
Lilly is paying up to $300 million for CrossBridge, according to deal terms announced Tuesday. The companies did not provide a financial breakdown, other than to say the sum spans an upfront payment and a subsequent payment for a development milestone that was not disclosed.
In an ADC, a toxic drug payload is delivered to a tumor by leveraging the targeting ability of an antibody. Houston-based CrossBridge develops ADCs engineered to carry two drug payloads. This approach is intended to provide a wider therapeutic index, the dose range that balances safety and efficacy. It can also address mechanisms that cancers use to develop drug resistance.
Lead CrossBridge program CBB-120 is designed to target TROP2, a protein expressed by many solid tumors including cancers of the breast and lungs. This target is already addressed by Trodelvy, a blockbuster ADC marketed by Gilead Sciences for treating certain breast and bladder cancers. Trodelvy’s drug payload inhibits topoisomerase 1, an enzyme that’s active in rapidly dividing cancer cells. CrossBridge’s dual-payload ADC carries a topoisomerase 1 inhibitor and an inhibitor of ATR, a protein that promotes the survival of cancer cells. An investigational new drug (IND) application for CBB-120 is expected this year.
CrossBridge was founded in 2023 based on ADC technology developed by Kyoji Tsuchikama, a professor of medicinal chemistry at the University of Texas Health Science Center at Houston. In 2024, CrossBridge announced $10 million in seed financing led by TMC Venture Fund and CE-Ventures. Last year, the Cancer Prevention and Research Institute of Texas awarded CrossBridge a $15 million grant to support IND-enabling studies for CBB-120.
“We look forward to seeing how Lilly advances our new generation of dual-payload antibody-drug conjugates, including CBB-120, with the potential to meaningfully improve outcomes for patients with limited treatment options,” CrossBridge co-founder and CEO Michael Torres said in a prepared statement. “At CrossBridge Bio, we believe our dual-payload ADC platform is uniquely positioned to be transformative in oncology.”
Lilly already has a presence in ADC R&D. Its clinical-stage pipeline includes sofetabart miptecan, an ADC designed to target folate receptor alpha to treat platinum-resistant ovarian cancer. This drug is currently in Phase 3 testing. In 2023, Lilly purchased Germany-based ADC developer Emergence Therapeutics. A Nectin-4-targeting ADC from the deal, ETx-22, is in preclinical development for urothelial cancer, according to Lilly’s annual report.
Lilly’s CrossBridge acquisition is the latest in a recent flurry of ADC business deals. Last week, Gilead announced a $3.15 billion deal to buy Tubulis, a clinical-stage ADC developer with platform technologies that yield ADCs with better stability and larger capacity to carry more drug payload. The week also included mega-financing rounds from startups Sidewinder Therapeutics and Stipple Bio, each developing new approaches to improving the targeting ability of ADCs.
Photo by Flickr user Paul Sableman via a Creative Commons license
