GSK Enters $1.9B Agreement to Develop Rare Cancer Treatments

GSK recently entered into a $1.9 billion agreement to acquire biopharmaceutical company Sierra Oncology to treat rare cancers.  

Myelofibrosis is a rare blood cancer that causes considerable scarring in the bone marrow, leading to severe anemia. At diagnosis, about 40% of patients are already anemic, and nearly all patients will eventually develop anemia.  

Sierra Oncology’s dual JAK1 and JAK2 inhibitor, momelotinib, can address the critical unmet needs of myelofibrosis patients with anemia. Momelotinib complements GSK’s prescription medicine Blenrep, building on GSK’s commercial and medical expertise in hematology.  

Recent studies found that momelotinib helped myelofibrosis patients with anemia and reduced the need for transfusions while also treating symptoms. 

In January 2022, Sierra Oncology announced that the MOMENTUM Phase 3 clinical trial met its primary and key secondary endpoints. Overall, momelotinib achieved a statistically significant and clinically meaningful benefit on symptoms, splenic response, and anemia. 

The proposed acquisition furthers GSK’s strategy to build a strong medicines and vaccines portfolio. GSK expects momelotinib will contribute to its growing specialty medicines business, with sales expected to begin in 2023.  

“Sierra Oncology complements our commercial and medical expertise in hematology. Momelotinib offers a differentiated treatment option that could address the significant unmet medical needs of myelofibrosis patients with anemia, the major reason patients discontinue treatment,” Luke Miels, chief commercial officer, GSK, said in the announcement.  

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

Myelofibrosis is a fatal cancer of the bone marrow impacting the normal production of blood cells. There are nearly 1.5 cases reported per 100,000 people annually in both men and women in the United States.  

Last month, FDA approved pacritinib (Vonjo) for patients with myelofibrosis based on data from Phase 2 and Phase 3 studies in over 600 patients assigned to receive pacratinib or the best available therapy. 

In the studies, pacritinib reduced spleen size by 35% or more, improved symptoms including fatigue by 50%, improved platelet counts, and reduced the need for transfusions.