GlaxoSmithKline (GSK) has signed an agreement for the acquisition of US-based late-stage biopharmaceutical company Sierra Oncology for a total equity price of $1.9bn (£1.5bn), or $55 for each share, in cash.

Sierra focuses on developing targeted therapies to treat rare kinds of cancer. 

Its differentiated therapy, momelotinib, can potentially address the crucial unmet medical needs of myelofibrosis patients with anaemia.

Momelotinib possesses inhibitory activity along crucial signalling pathways. This activity could provide beneficial treatment effects on anaemia and lessen transfusion requirements while treating symptoms. 

In January this year, the company reported positive topline data from the Phase III MOMENTUM clinal trial of momelotinib.

Findings showed that the trial met all the primary and key secondary endpoints and momelotinib offered a statistically significant and clinically meaningful benefit on symptoms, anaemia and splenic response.

GSK noted that momelotinib complements its Blenrep (belantamab mafodotin), expanding the company’s commercial and medical capabilities in haematology. 

Sierra had plans to make a regulatory submission in the US in the second quarter and submission in the EU in the second half of this year.

Apart from momelotinib, Sierra’s pipeline comprises two assets, SRA515 and SRA737, which are currently in the Phase I development stage. 

The proposed deal is in line with the goal of GSK in establishing a robust portfolio of new speciality therapies and vaccines. 

GSK chief commercial officer Luke Miels said: “Momelotinib offers a differentiated treatment option that could address the significant unmet medical needs of myelofibrosis patients with anaemia, the major reason patients discontinue treatment. 

“With this proposed acquisition, we have the opportunity to potentially bring meaningful new benefits to patients and further strengthen our portfolio of speciality medicines.”

The deal is anticipated to conclude in the third quarter of this year or earlier subject to necessary conditions and approvals.

In March this year, GSK and LifeMine Therapeutics signed a research and development collaboration to detect small molecule leads.