CHMP backs GSK’s momelotinib for myelofibrosis

GSK is on the brink of EU approval for JAK inhibitor momelotinib as a treatment for myelofibrosis patients with anaemia, after the EMA’s human medicines committee issued a positive opinion on the marketing application.

At its November meeting, the CHMP recommended the drug under the Omjjara trade name for the treatment of disease-related splenomegaly or symptoms in adult patients with moderate-to-severe anaemia who have primary myelofibrosis, post-polycythaemia vera myelofibrosis, or post-essential thrombocythaemia myelofibrosis.

The drug – which was the principal asset in its $1.9 billion acquisition of Sierra Oncology last year and has been predicted by GSK to have blockbuster sales potential – was approved as Ojjaara by the US FDA in September after a three-month delay.

If approved by the European Commission, which usually occurs in the weeks following a CHMP recommendation, the once-daily oral JAK1/JAK2 and activin A receptor type 1 (ACVR1) inhibitor will become the first and only treatment in the EU specifically indicated for myelofibrosis patients with moderate to severe anaemia.

It can be used in patients who have either not been treated with JAK inhibitors before or those who have previously received Novartis’ Jakavi (ruxolitinib), a widely used myelofibrosis therapy.

In clinical trials, Omjjara achieved reductions of 50% or more in disease-related symptoms and at least 35% reductions in spleen volume in patients, according to the CHMP. The most common side effects with treatment are diarrhoea, thrombocytopenia, and nausea.

Approval for first-line use in both Europe and the US is a boost for GSK, which at one point had been expecting the drug to be reserved for second-line use in patients previously treated with Jakavi (known as Jakafi in some markets) or other JAK drugs, like Bristol Myers Squibb’s Inrebic (fedratinib) and CTI Biopharma’s Vonjo (pacritinib).

According to Nina Mojas, head of oncology product strategy at GSK, momelotinib offers a “differentiated mechanism of action” compared to other drugs in the JAK class.

“The vast majority of myelofibrosis patients will develop anaemia, causing them to require transfusions and leading a notable proportion to discontinue treatment,” she said. “This positive CHMP opinion is a significant step in bringing momelotinib to patients in the EU with this difficult-to-treat blood cancer.”

Current therapies for myelofibrosis can help relieve symptoms of myelofibrosis and improve long-term survival, but can exacerbate anaemia, a common symptom of the blood cancer. Anaemia is the main reason for myelofibrosis treatment discontinuation, which occurs in around 30% of patients.