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GSK acquires Sierra Oncology for 1.9bn

GlaxoSmithKline acquires California-based Sierra Oncology and a ready-for-approval product candidate for myelofibrosis.

GSK is paying $1.9 bn in cash ($55 per share) for the deal. This is a 39 per cent premium to the Sierra share price on 12 April and a 63 per cent premium to the volume-weighted average price of the preceding 30 days. The takeover will give GSK control of momelotinib, a Janus kinase (JAK) inhibitor that met all endpoints in a phase III head-to-head trials with the rival drug Jakafi (danazol, Novartis AG/Incyte) that enrolled 195 patients (130 received momelotinib, 65 danazol) with the blood cancer myelofibrosis.

According tzo GSK, at diagnosis, approximately 40% of patients with myelofibrosis are anaemic, and it is estimated that nearly all patients will eventually develop anaemia while only 20% die. While patients treated with danazol often require transfusions, and more than 30% discontinue treatment due to anaemia, 31% of momelotinib patients were transfusion independent at Week 24.

The U.S. regulatory filing is expected to be submitted during the current quarter. European-wide market clearance is expected to be filed in the second half of this year. GSK expects first revenues from momelotinib sales starting in 2023, and is confident the drug has “siginficant growth potential” in the medium term and will have a positive impact on operating profit margins. Sierra reports net loss of nearly $95m for 2021.