Merck’s Four-Week Hepatitis C Regimen Fails to Top Gilead

Merck & Co. won’t move forward with an ultra-short hepatitis C regimen that attempted to cut treatment durations in half by combining two of its drugs with another from Gilead Sciences Inc.

Patients in the mid-stage, 102-person trial got Merck’s experimental drugs grazoprevir and elbasvir, along with Gilead’s Sovaldi, for as little as four weeks, with the length of treatment based partly on how severe their infection was.

In patients whose livers weren’t already badly damaged by the virus, 38.7 percent were cured in four weeks and 86.7 percent were cured in six weeks, according to data presented today at the American Association for the Study of Liver Diseases conference in Boston.

That’s well below the 90 percent-plus cure rates seen with longer treatments. Merck won’t take the four-week course into a new round of testing, said Eliav Barr, the company’s vice president of infectious diseases.

Gilead’s drugs Sovaldi and Harvoni are already approved and are on track to become among the best-selling medicines in history. Harvoni, a combination of Sovaldi and a second drug, has shown cure rates as high as 99 percent after 12 weeks of treatment.

Merck, along with its competitors, is testing its hepatitis C drugs in different patient types to find the shortest and most effective durations for each. The medicines are part of a new generation of treatments that does away with side effect-heavy injections, works faster and is more likely to clear the virus.

Gilead Gains

Today’s data removes a “medium-term competitive overhang” for Gilead, “indicating that getting down to treatments durations of less than eight weeks” could be a challenge, wrote Brian Abrahams, a Wells Fargo & Co. analyst, in a note to clients today.

Gilead shares gained less than 1 percent to $106.99 at the close in New York. Merck shares fell less than 1 percent to $58.81.

The companies are vying for a bigger piece of a market that will reach $15 billion by 2016, according to Credit Suisse Group AG. About 3.2 million people in the U.S. have hepatitis C, according to the Centers for Disease Control and Prevention.

Merck’s trial also tested patients whose liver had been damaged by the viral infection, a condition called cirrhosis. Of those, 80 percent were cured in six weeks of therapy, and 94.7 percent were cured in eight weeks.

New Tests

The drugmaker also said that it will start testing two other new three-drug regimens, adding grazoprevir and elbasvir in combination with MK-3682 in one test and grazoprevir together with MK-3682 and MK-8408 in another. Those trials will start at eight weeks of treatment, with the option to go to six weeks.

Merck, based in Whitehouse Station, New Jersey, acquired MK-3682 with its $3.85 billion purchase of Idenix Pharmaceuticals Inc. The Idenix drug uses the same mechanism as Sovaldi to attack the liver virus.

The short-duration tests showed Merck the limits of the new drugs. “The key thing for me was having a clear road map” for the next trial, Merck’s Barr said in an interview. “I was afraid it’d be a pastiche of results difficult to interpret, whereas this clearly shows the Achilles’ heel in terms of duration.”

Merck’s ultimate aim, said Barr, is to create a one-pill combination that works in all of the six known strains of the disease.

Upper Hand

For the current generation of treatments, Gilead has the upper hand. Merck and AbbVie Inc., which is also developing a drug combination, don’t yet have faster or better regimens. That has led to speculation that the two companies might try and gain market share by cutting the price of their drugs, said Vamil Divan, an analyst at Credit Suisse.

Gilead has come under scrutiny by lawmakers and criticism from insurers for the price tag of Sovaldi, which costs $84,000 for a 12-week regimen. Harvoni, approved in October, combines Sovaldi with another drug, ledipasvir, for an all-oral combination that eliminates the need for additional therapies, which often include injections. Harvoni will cost $94,500 for a 12-week treatment and $63,000 for eight weeks.

Next year, Merck plans to submit for regulator approval its experimental two-drug combination that in interim results has shown a 98 percent cure rate in patients with the most common strain of the disease after 12 weeks of treatment. The combination could target patients with kidney disease who don’t tolerate Sovaldi well, Barr said.

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