In an arrangement that may hamper Vertex Pharmaceuticals' success in the burgeoning hepatitis C protease inhibitor market, Merck and Roche have agreed to co-promote Merck's recently approved rival Victrelis (boceprevir) in the U.S.

The deal, for which no financial details were revealed, may expand to include additional territories as Victrelis gains additional regulatory approvals worldwide. It also commits the two pharmas to work together on trials in which boceprevir will be tested in combination with other direct-acting antivirals the companies have in development for HCV.

Merck and Roche are the current market leaders in HCV, with Merck selling backbone therapies PEG-Intron (pegylated interferon alfa 2b) and Rebetol (ribavirin), and Roche marketing Pegasys (pegylated interferon alfa 2A) and Copegus (ribavirin). Roche largely has won the interferon battle, commanding the lion's share of that market, and now Merck can tap into its rival's success at marketing HCV therapies. The companies were careful to note that their interferon franchises remained "very separate and independent."

The label for boceprevir, which was approved by FDA on May 13, specifies that the drug must be used in tandem with pegylated interferon and ribavirin, the existing standard of care for HCV (Also see "Merck To Ship Hepatitis C Drug Victrelis To Pharmacies Within A Week" - Pink Sheet, 13 May, 2011.). In addition to the Merck and Roche branded versions, ribavirin also is available in generic form from Aurobindo and Sandoz, the generic drug division of Novartis AG.

Vertex's competing protease inhibitor Incivek (telaprevir) has an FDA approval date of May 23 and is considered very likely to be approved, meaning Merck should have less than a two-week advantage out of the gate in marketing boceprevir. Market analysts generally anticipate that telaprevir will command a larger share of the market because of superior efficacy findings in clinical trials.

The terms of the non-exclusive arrangement between Merck and Roche specify that Roche representatives will include boceprevir as part of their promotion to health care providers on the use of Pegasys in triple combination therapy for HCV. A Roche spokesperson clarified that Roche reps will detail boceprevir to doctors using Merck-approved materials, but that boceprevir will not be sold in a bundle with Pegasys and/or Copegus. A Merck spokesperson stressed that the arrangement will "not alter the economics of Victrelis for Merck."

Co-Promotion Pact Pairs Boceprevir With Leading Peg-Interferon

Bernstein Research analyst Tim Anderson in a May 17 note called the agreement one "that we would not have envisioned" but a smart play by Merck as it will effectively partner boceprevir with Pegasys, which has emerged as the product of choice in the peg-interferon market, with a U.S. market share of roughly 75%.

Merck primarily studied boceprevir in tandem with its own PEG-Intron, although one study did demonstrate that the protease inhibitor could be used with either peg-interferon. "With Roche on board, this potential shortcoming gets more than removed in our opinion," Anderson wrote. "This is further buttressed by Victrelis' label that implies the drug works with either pegylated interferon."

Although the Merck/Roche agreement is non-exclusive, Anderson opined that Roche is unlikely to also team up with Vertex. (Vertex already is partnered with Johnson & Johnson to commercialize telaprevir in Europe and has said it plans to launch and market the drug on its own in the U.S.)

"In essence, the Merck/Roche agreement effectively tries to shut telaprevir out of the market to some degree," Anderson said. He notes that Victrelis' competitive position is "undoubtedly strengthened by the new collaboration" but that it does nothing to prevent physicians from prescribing Vertex's drug.

Under the agreement, Merck and Roche also will collaborate to examine novel combinations of marketed and investigational medicines from both companies in the treatment of HCV. Many companies developing therapies for HCV are testing combos that pair protease inhibitors with drugs with other mechanisms of action, including polymerase inhibitors.

Roche already is collaborating with Pharmasset Inc. to develop the Phase II polymerase inhibitor RG7128 and brings the Phase II protease inhibitor danoprevir (RG7227) and Phase I polymerase inhibitor RG7432 to its partnership with Merck. Merck's pipeline of HCV candidates at present is limited to protease inhibitors, including the follow-on vaniprevir (MK-7009) currently in Phase IIb. It also has MK-7152 in Phase I.

-Joseph Haas (j.haas@elsevier.com)

Merck/Roche Co-Promote Pact Attempts To Shut Vertex Out Of HCV Protease Inhibitor Space

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