Merck And AiCuris Report Phase 2 Results Of Antiviral Letermovir

AiCuris and Merck announced positive results from the Phase II trial of the investigational antiviral agent letermovir in bone marrow transplant patients.

Professor Helga Rübsamen-Schaeff, CEO of AiCuris, said, “We are very pleased to see the encouraging data regarding the efficacy and tolerability of our innovative drug for treatment of CMV infection among transplant recipients published in this prestigious journal. We are looking forward to the start of Phase 3 clinical testing.”

The double blind, placebo-controlled, randomized, Phase II trial assessed the efficacy and safety of letermovir for the prevention of human cytomegalovirus (CMV) infection in patients undergoing bone marrow transplant. The drug in CMV-seropositive allogeneic human blood precursor cell recipients (bone marrow transplant patients) met the study’s two primary efficacy endpoints. The primary endpoint of all-cause prophylaxis failure in the modified intention-to-treat (mITT) population was observed to be lower compared to the placebo population. Incidence of virologic failure was also lower in other lower-dosage and placebo groups compared to the 240 mg group. Equally important is that the time to the onset of prophylaxis failure, a co-primary endpoint in the trial, was markedly shorter in the 240 mg group than in the placebo group.

Letermovir is derived from the novel chemical class quinazolines and is designed to inhibit the HCMV viral terminase. The investigational drug has been awarded Orphan Product Designation by the European Medicines Agency and the U.S. Food and Drug Administration (FDA). The FDA has also granted Fast Track Status to letermovir in the U.S.

The Human Cytomegalovirus causes severe, life-threatening infections in immuno-compromised patients, such as HIV/AIDS patients, newborn babies, and transplant recipients. The infection is characterized by leucopenia or very low white blood cell count, fever, and thrombocytopenia. HCMV infection is prevented through pre-emptive treatment or the use of anti-HCMV drug prophylaxis such as letermovir.

Results of the trial were published in the latest issue of the New England Journal of Medicine. Merck announced that it plans to conduct a Phase III trial for the investigational agent letermovir in the second quarter of 2014.