Alexion bags option on Caelum to boost hematology franchise

Alexion has gained an option to buy Caelum Biosciences for its light chain (AL) amyloidosis candidate. The deal sees Alexion take an equity stake in the Fortress Biotech subsidiary and commit to a package that could top $500 million.

Caelum landed the deal on the strength of the potential of its lead drug CAEL-101, a fibril-reactive monoclonal antibody designed to bind to kappa and lambda misfolded proteins. Through this action, Caelum thinks CAEL-101 can reduce or eliminate the amyloid deposits that build up around tissues in patients with the rare disease AL amyloidosis and cause progressive organ damage.

Alexion is convinced of both the unmet need in AL amyloidosis and the potential for CAEL-101 to address it. 

“With a median survival time of less than 18 months following diagnosis and no approved therapies to address the organ damage caused by AL amyloidosis, there is a significant need for new treatments for this devastating disease,” Alexion R&D chief John Orloff said in a statement. “We believe CAEL-101 holds significant promise in being able to help these patients and we’re excited to add it to our growing clinical-stage rare hematology portfolio.”

Having identified CAEL-101 as a good fit for its hematology franchise, Alexion has agreed to pay up to $60 million in the form of an investment and development funding payments linked to milestones. If Alexion exercises its acquisition option after seeing phase 2 data, it will pay up to $500 million in upfront and milestone fees. 

Striking the deal gives Caelum financial and developmental support as it heads toward the phase 2 readout that will dictate the future of CAEL-101. Alexion will provide input on the design of the phase 2, but Caelum will retain responsibility for the study and production of clinical materials.

Caelum wrapped up its previous trial of CAEL-101, a phase 1a/1b study, in 2017. Of the 24 evaluable patients treated in the study, 14 experienced an organ response. No dose-limiting or grade 4 or 5 toxicities were seen in the study.

Shares in Fortress Biotech, which owns around 40% of Caelum, jumped following the news.