Jazz pays $75M for chance to buy into ImmunoGen ADCs

Jazz is paying $75 million and committing to $100 million in R&D funding to buy into ImmunoGen’s early-stage pipeline. The deal gives Jazz an option to pick up worldwide rights to two hematology antibody-drug conjugates (ADCs) and a third as-yet-unidentified program.  

IMGN779 is the most advanced of the candidates. ImmunoGen moved the CD33-targeted ADC into testing in patients with acute myeloid leukemia last year. The second candidate, anti-CD123 ADC IMGN632, is due to follow the collaboration’s lead candidate into the clinic later this year.

Jazz can opt-in to the programs at any time up to the start of a pivotal trial in return for about $50 million. Alternatively, Jazz can wait until ImmunoGen is nearly ready to file a BLA and opt-in for a fee just north of $100 million. Either way, ImmunoGen will get another payday when the drug is approved and then start pulling in royalties, the size of which will depend on when Jazz opted-in. The royalties top out just above 20%.   

The variation in royalties reflects the effect of the time Jazz opts-in on its financial contributions to the programs. Jazz will share costs once it opts-in.  

That is one of several flexible components of the deal. ImmunoGen can also choose to co-promote one drug, perhaps two "under certain limited circumstances," in the U.S. to claim a share of the profits rather than milestones and royalties. 

The deal forms part of string of transactions ImmunoGen has struck to strengthen its cash position. The sequence started in May when ImmunoGen unveiled back-to-back deals with Debiopharm and Sanofi. ImmunoGen pulled in $55 million in upfront fees through the deals, leading it to increase its anticipated end-of-year bank balance to about $95 million and extend its runway out into the back half of next year.

Boosted by $75 million from Jazz, ImmunoGen’s financial future is now secured for longer still. One beneficiary of ImmunoGen’s renewed financial strength is mirvetuximab soravtansine, the firm’s wholly-owned folate receptor alpha-targeting ADC. The asset is now in phase 3. And, with deals for other drugs providing cash, ImmunoGen has the freedom to retain the rights to the drug unless a particularly-juicy deal comes along.

The thinking behind the desire to hold on to the U.S. and, unless the terms are right, the ex-U.S. rights, for mirvetuximab is evident in the Jazz terms. ImmunoGen CEO Mark Enyedy has spoken of wanting to keep a stake in assets through co-development and commercialization deals to extract long-term value from ADCs. The retention of rights to mirvetuximab and co-commercialization option in the Jazz deal reflect this thinking.