Merck’s (MRK) hepatitis C virus (HCV) treatment, Victrelis (boceprevir) will soon get a new safety update in its label. Merck recently issued a “Dear Doctor” letter informing healthcare professionals about drug interactions between Victrelis and certain ritonavir-boosted HIV protease inhibitors (atazanavir, lopinavir, darunavir).
Merck presented results from a pharmacokinetic study which evaluated drug interactions between Victrelis and ritonavir-boosted HIV protease inhibitors in healthy volunteers (n=39). Results showed that the use of Victrelis with the HIV medicines together could potentially reduce the effectiveness of the medicines.
Merck said that the drug interactions could be clinically significant for patients suffering from both chronic HCV and HIV. We note that Victrelis is not indicated for use in patients who are infected with both HIV-1 and chronic HCV.
The FDA has notified both healthcare professionals and patients about these drug interactions and intends to update Victrelis’ label to include information regarding the same.
The agency said that patients should not discontinue their medicines without consulting their healthcare professionals first. Healthcare professionals have been asked to closely monitor patients who have been prescribed both Victrelis and the HIV medicines.
Victrelis, which was approved in May 2011, posted sales of $87 million in the fourth quarter of 2011. Although sales increased on a sequential basis, Victrelis sales are lagging significantly behind Vertex Pharmaceutical’s (VRTX) Incivek, which posted fourth quarter 2011 sales of $456.8 million .
Merck has an agreement with Roche (RHHBY) for the global marketing of Victrelis as part of a triple combination therapy. Victrelis is available in the US and several other countries.
We currently have a Neutral recommendation on Merck, which carries a Zacks #3 Rank (short-term “Hold” rating). Victrelis sales could be affected further by the updated label as quite a large number of patients are co-infected with HCV and HIV.
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