- AstraZeneca on Wednesday said it will exercise an option to buy the rest of rare disease drugmaker Caelum Biosciences for $150 million, betting on the promise of an experimental medicine to treat light chain amyloidosis.
- The U.K. drugmaker inherited the option along with its $39 billion acquisition of Alexion that was announced late last year. Under deal terms, AstraZeneca's Alexion unit may also make as much as $350 million in additional payments to Caelum should certain regulatory and marketing milestones be met.
- AstraZeneca said it expects the purchase to close on Oct. 5, after which Caelum will receive the $150 million option exercise fee.
Light chain, or AL, amyloidosis has been a tough target for drugmakers. Caused by defective plasma cells, the disease results in misfolded amyloid proteins that can build up in organs and cause organ failure or death. About 4,500 new cases are diagnosed each year in the U.S.
Caelum's drug, dubbed CAEL-101, is an antibody that binds to the misfolded proteins. AstraZeneca views the drug as promising, noting in a statement its potential to remove amyloid deposits from tissue and improve organ function.
The Food and Drug Administration has granted both Orphan Drug and Fast Track designations to CAEL-101, both incentives that help encourage development of rare disease drugs and speed their review if studies are successful. CAEL-101 is currently being tested in Phase 3 trials.
Earlier this year, Johnson & Johnson won an accelerated FDA approval for its blood cancer medicine Darzalex Faspro to treat newly diagnosed light chain amyloidosis based on results from a study of nearly 400 patients.
Other drugmakers have stumbled in attempts to develop drugs for AL amyloidosis, though. Takeda tried to develop its Ninlaro multiple myeloma medicine for the disease and in 2019 reported a Phase 3 study had failed. Earlier that year, GlaxoSmithKline gave up on an experimental combination of two drugs after studying them for the condition.
Prothena, meanwhile, discontinued development of an experimental candidate in 2018, only to revive it a year later after continued analysis suggested the therapy might have a benefit for the patients at highest risk of early death from the disease. That drug, birtamimab, is now in Phase 3 testing.
With the purchase of Alexion, AstraZeneca has significantly expanded its rare disease drug research. Last month, the company reported positive Phase 3 trial results for an Alexion medicine to treat Wilson disease.