The pharmaceutical industry’s antibody-drug conjugate( ADC) deal spree continues.
AbbVie says it will buy ImmunoGen for about $10 billion, adding to a series of multi-billion dollar acquisitions built around ADCs. Just a month ago, Merck & Co. paid Daiichi Sankyo$ 4 billion to work together on three of these anticancer agents, and Pfizer should soon complete its acquisition of the ADC expert Seagen for $43 billion. Gilead Sciences bought Immunomedics, another ADC firm, for $21 billion in 2020.
The centerpiece of the latest deal is ImmunoGen’s Elahere (mirvetuximab soravtansine), a first-in-class ADC that the US Food and Drug Administration approved in 2022 for ovarian cancer.
Elahere consists of an antibody that binds the folate receptor alpha (FRα) on the surface of ovarian cancer cells linked to a soravtansine payload that kills the cells by interfering with the cell cycle. It is the first ADC to target FRα and the second to use a small-molecule payload derived from maytansine, a natural product first isolated from the flowering shrub Maytenus serrata.
Global sales of Elahere could reach $684 million in 2025, forecast analysts at the investment bank William Blair. “We see it as a good fit for AbbVie, which needs new growth drivers,” write William Blair’s Andy Hsieh and colleagues in a note to clients on the deal. AbbVie’s arthritis treatment Humira (adalimumab), the best-selling drug of all time, is starting to face biosimilar competition. The firm’s cancer treatment Imbruvica (ibrutinib), its second-best seller, is seeing increased competition from similar inhibitors.
“In our view, the ADC modality continues to present as one of the most prized possessions from both a big pharma business development and investor perspective,” the analysts write. The ImmunoGen acquisition will also speed up AbbVie’s progress in the solid tumor space, they add.
ImmunoGen has three other ADCs in clinical trials. Pivekimab sunirine, an anti-CD123 antibody attached to a novel indolinobenzodiazepine payload, is in Phase 2 trials for a rare blood cancer. IMGN-151, a next-generation FRα-targeted ADC, is in Phase 1 trials for ovarian cancer and IMGC936, an anti-ADAM9 ADC, is also in Phase 1 trials for multiple solid tumor types.
The hunt is on for more targets, linkers, and payloads that can broaden the reach of ADCs. Nurix and Seagen partnered earlier this year to combine antibodies with targeted protein degraders. AbbVie’s own Phase 1 candidate ABBV-319, for blood cancers, combines an antibody with a steroid payload.
AbbVie has also long been trying to push ADCs beyond oncology with antibodies conjugated to steroids for immunological diseases. Earlier this year it discontinued development of its once-lead clinical candidate in this space, ABBV-154.