Boehringer Ingelheim has rolled into an alliance with undruggable target specialist Circle Pharma, putting together a package potentially worth up to $607 million to secure the rights to a preclinical cancer program.
Circle burst onto the scene 10 years ago, emerging with seed funding from Pfizer and two collaborations with the Big Pharma to develop cell permeable macrocyclic peptide therapeutics. Interest in the biotech was built on a belief it may be able to realize the potential of macrocycle drugs, a class of molecules with the potential to bind to challenging sites.
The therapeutic use of macrocycle molecules dates back decades but most products and drug candidates are based on natural products. Circle’s platform uses structure-based rational drug design and synthetic chemistry to discover cell-permeable macrocycles.
Boehringer has identified the technology as a good fit for its oncology strategy. The German drugmaker has zeroed in on proteins that drive the growth of tumor cells as attractive targets for cancer drugs. That focus aligns with work at Circle, which has discovered macrocycles that directly inhibit the cyclin proteins that regulate cell division.
Toxicity and low selectivity have hindered the targeting of cyclin-dependent kinases to date. Boehringer’s belief Circle may have found a solution to those problems informed its decision to bet up to $607 million on the program. Neither party has disclosed the size of the upfront fee, which typically makes up a small part of the overall package in deals for preclinical assets.
The Boehringer program, which could target multiple cancers, is the only asset in Circle’s public pipeline with a partner. Circle has attracted Big Pharma attention throughout its history, with investment from Eli Lilly following the engagement with Pfizer, but owns all its disclosed assets. The pipeline is led by a cyclin A/B RxL inhibitor that Circle took into the clinic in August. Circle raised $90 million to fund the trial.