The US Food and Drug Administration yesterday approved Prevymis (letermovir) tablets and injection, the first drug indicated to help prevent CMV (cytomegalovirus) infection and disease in adults who have been exposed to CMV and have received an allogeneic hematopoietic stem cell (bone marrow) transplant (HSCT).
The news pushed the shares of the drug’s maker, Merck & Co (NYSE: MRK), up 1.78% to $56.58 by close of trading yesterday.
Merck purchased worldwide rights to develop and commercialize letermovir from AiCuris GmbH in 2012 for around $570 million. The drug is also under review in Europe, where it has been granted orphan designation.
Among the more than 27,000 allogeneic HSCTs performed each year worldwide (including approximately 8,500 transplants in the USA), an estimated 65%-80% of recipients have been previously exposed to CMV and are therefore at high risk for CMV infection. Without prophylactic measures, many patients undergoing allogeneic HSCT will experience CMV infection, which can cause a range of serious negative health outcomes in this population. In a randomized controlled trial evaluating Prevymis as a preventive therapy in patients that had undergone an allogeneic HSCT, patients receiving Prevymis had a lower incidence of CMV infection than those receiving a placebo control.
According to Credit Suisse analysts, letermovir could grow quickly to reach $370 million in sales by 2020. However, the drug could see a rival in the shape of Chimerix’ brincidofovir, which is being tested not only for prevention of CMV but also other opportunistic infections that can affect HSCT patients.
The FDA granted this application Breakthrough Therapy and Orphan Drug designation, the latter of which provides incentives to assist and encourage the development of drugs for rare diseases.
The most common Prevymis side effects include nausea, diarrhea, vomiting, swelling in the arms and legs, cough, headache, tiredness and stomach (abdominal) pain. Prevymis is contraindicated in patients receiving pimozide and ergot alkaloids and in patients receiving pitavastatin or simvastatin when co-administered with cyclosporine.