This article has been updated to include pricing information for the upsized public offering.
NEW YORK – ImmunoGen on Thursday announced a proposed public offering to sell $325 million in shares of its common stock.
The firm will offer 26,000,000 shares of its common stock at a price of $12.50 per share. ImmunoGen will also offer the underwriters a 30-day option to purchase up to 3,900,000 shares of its common stock at the public offering price. The offering is expected to close on May 9.
Jefferies, Goldman Sachs, and Guggenheim Securities are joint book-running managers on the offering, and Canaccord Genuity is serving as lead manager.
The firm will use the proceeds to support global commercialization activities and supply for its folate receptor alpha (FRα)-directed antibody Elahere (mirvetuximab soravtansine-gynx), along with clinical trial activities, pipeline research and development activities, business development activities, and capital expenditures, according to a filing with the US Securities and Exchange Commission.
Elahere was approved in the US last year for patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received up to three prior systemic treatments. ImmunoGen is also working with NeoGenomics on a biomarker testing program to identify patients whose tumors express the FRα protein for treatment using Roche's Ventana FOLR1 (FOLR1-2.1) RxDx assay.
ImmunoGen, based in Waltham, Massachusetts, is also studying Elahere in earlier lines of therapy and in combination trials. The firm has several other precision oncology candidates in its pipeline including drugs targeting CD123 and ADAM9, and other programs targeting FRα.