Harpoon Therapeutics, a US-based immuno-oncology drug developer that counts pharmaceutical firms Eli Lilly and Taiho as investors, floated on Friday in a $75.6m initial public offering.
The offering consisted of 5.4 million shares issued on the Nasdaq Global Select Market and priced at $14 each, in the middle of its $13 to $15 range, valuing the company at approximately $334m. They debuted at $14.00 each on Friday before closing at $13.50.
Founded in 2015, Harpoon is developing T cell engagers meant to leverage the body’s immune system to treat diseases including cancer, by getting T cells to kill cells expressing specific proteins which are carried by the target cells.
Harpoon will put $67m of the IPO proceeds into taking its lead product candidate, HPN424, through a phase 1 clinical trial for metastatic castration-resistant prostate cancer and into phase 2 testing, and a second candidate, HPN536, into clinical development for ovarian cancer.
Lilly Asia Ventures and Taiho Ventures, respective subsidiaries of Eli Lilly and Taiho, joined OrbiMed, MPM Capital, Arix Bioscience, New Leaf Venture Partners Cormorant Asset Management, NS Investment, UBS Oncology Impact Fund and Ridgeback Capital Investments for Harpoon’s $70m series C round in November 2018.
The company had raised $45m in a mid-2017 series B round co-led by Arix Bioscience and New Leaf Venture Partners and backed by Taiho Ventures and MPM Capital, the latter of which had invested an undisclosed sum in the company the previous year.
MPM Capital remains the company’s largest investor, with a 23.2% stake diluted to 17.9% in the offering, followed by UBS Oncology Impact Fund (15.5% post-IPO), New Leaf (10.7%), Arix (10.5%) and OrbiMed (8.9%).
Existing shareholders agreed to buy $40m of shares in the IPO, but Harpoon did not disclose their identity, and the stake sizes above do not reflect any purchases made in the offering.
Citigroup and SVB Leerink are joint book-running managers for the IPO while Canaccord Genuity and Wedbush PacGrow are co-managers. They have 30 days to buy another 810,000 shares that would lift the size of the offering to approximately $87m.
