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Seragon’s SERDs entice Genentech into potential $1.725 billion buy

By Marie Powers, Staff Writer

Roche AG unit Genentech is plunking down $725 million in cash, plus contingent milestone-based payments of up to $1 billion, to acquire Seragon Pharmaceuticals Inc. and its portfolio of oral selective estrogen receptor degraders (SERDs), designed to treat hormone receptor-positive breast cancer.

Richard Scheller, executive vice president and head of Genentech Research and Early Development, explained the price of the deal by commenting in a statement that “We believe these investigational oral SERDs could one day redefine the standard of care for hormone receptor-positive breast cancer.”

Up to half of the 40,000 U.S. women who die from breast cancer each year have a form of the disease driven by the estrogen receptor, according to Genentech.

Seragon rose to the top quickly. The privately held San Diego biotech was spun out of Aragon Pharmaceuticals Inc. in August 2013 just prior to Aragon’s acquisition by Johnson & Johnson. The company’s leadership also remained largely intact, led by former Aragon CEO Richard A. Heyman, with the rest of the management team comprising other former Aragon execs – Edna Chow Maneval, Patricia Millican and Nicholas Smith – and board members who had previously helped shepherd Aragon, including Chairman Peter Svennilson, of the Column Group. (See BioWorld Today, June 18, 2013.)

In October 2013, Seragon landed a $30 million series A round that included investors Venbio, Topspin Fund, Aisling Capital, Orbimed Advisors and the Column Group. All had participated in Aragon’s $50 million series D round the previous year. (See BioWorld Today, Oct. 5, 2012, and Oct. 17, 2013.)

Seragon’s SERDs are designed to both block estradiol action at the estrogen receptor and also to clear the estrogen receptor from the cell altogether. SERDs are believed to change the shape of the estrogen receptor in a manner that targets it for elimination by the cell, offering a dual-acting approach to treating hormone receptor-positive breast cancer and, potentially, other cancers driven by the estrogen receptor.

Seragon’s lead product candidate, ARN-810, is a next-generation SERD in phase I trials for patients with hormone receptor-positive breast cancer who failed existing hormonal agents. Seragon has a second SERD candidate with potential in ER-positive breast cancer as well as ER-positive endometrial and ovarian cancer.

Next-generation SERDs nicely complement Genentech’s existing therapies in breast cancer, including Avastin (bevacizumab), Herceptin (trastuzumab), Kadcyla (ado-trastuzumab emtansine) and Perjeta (pertuzumab), as well as programs in development by South San Francisco-based Genentech and parent Roche.

“Although medicines have been approved for the treatment of hormone receptor-positive breast cancer disease for decades, this disease still accounts for half of all breast cancer deaths,” said James Sabry, senior vice president and global head of Genentech Partnering, adding that the acquisition could “advance our breast cancer research by years.”

The Seragon transaction is expected to close in the third quarter, subject to customary conditions, including clearance under the Hart-Scott-Rodino Act. Seragon’s portfolio will be integrated into Genentech Research and Early Development.

See the next edition of BioWorld Today for more on this story.