Biotech Values

[DewDiligence]

Boceprevir Briefing Docs Have No Smoking Gun

[FDA staffers do not appear to be unduly concerned about anemia, which has been the purported Achilles heel of Boceprevir. Approval would seem to be very likely.]

http://www.reuters.com/article/2011/04/25/merck-hepatitis-idUSN2513073820110425

›Mon Apr 25, 2011 4:49pm EDT
By Lisa Richwine

WASHINGTON, April 25 (Reuters) - A proposed Merck & Co (MRK) medicine eliminated the liver-destroying hepatitis C virus although anemia and other safety concerns remained for the potential blockbuster pill, U.S. drug reviewers said.

Food and Drug Administration staff, in documents released on Monday, also noted suicidal and homicidal thoughts reported by a small number of patients.

Industry analysts said the safety findings were not strong enough to derail the drug given its high cure rate for a disease that infects tens of millions of people around the world. Analysts said they expected an advisory panel to recommend approval on Wednesday.

The pill, boceprevir, and a proposed rival from Vertex Pharmaceuticals Inc (VRTX) are considered possible blockbuster products because of their potential to cure far more people and in as little as half the time of standard drugs. Current therapies require almost a year of treatment and often cause flu-like symptoms that are tough to tolerate.

Merck shares rose 0.9 percent to close at $34.33 on the New York Stock Exchange. Vertex shares fell 2.7 percent to close at $48.04 on the Nasdaq.

Many Vertex investors were expecting "a materially worse review of Boceprevir, which doesn't look like that may happen," JPMorgan analyst Geoff Meacham said.

About 3.2 million Americans and 170 million people worldwide have hepatitis C, a bloodborne disease that can lead to chronic liver problems, liver cancer, cirrhosis and death.

In two Merck-funded studies, 66 percent of patients given boceprevir plus standard therapy had a "sustained virologic response" (SVR), meaning the virus was not detectable in the blood. SVR is considered a cure.

For older therapies, the SVR rate was 38 percent. Patients had not been treated previously for hepatitis C.

The FDA staff said they generally agreed with Merck's assessment of the drug's effectiveness.

Vertex has reported cure rates as high as 75 percent for its drug, telaprevir. The FDA is set to release its preliminary analysis of the Vertex data on Tuesday, and an advisory panel will review the medicine on Thursday.

SAFETY ISSUES NOT SEEN AS DEAL-BREAKERS

On the Merck drug, the FDA reviewers said they will ask outside advisers to consider an increase in the frequency and severity of anemia, a deficiency of red blood cells that can cause fatigue and other problems.

Another "potential safety signal" is a small number of reports of psychiatric symptoms such as suicidal and homicidal thoughts, the FDA reviewers said.

But they added it was "difficult to make any meaningful clinical conclusions" about the cases. The same symptoms have been reported with pegylated interferon, one of the hepatitis treatments also given to patients in the studies.

Meacham said the staff comments were in line with expectations and supported a positive recommendation for approval. The focus on anemia was expected and the issue "doesn't look to be a deal-breaker," Meacham said in a research note.

He said the psychiatric issue was new but noted the symptoms already were linked with the other treatment.

About 1 percent of patients treated with boceprevir reported suicidal thoughts compared with less than 1 percent in a control group, the FDA staff said. Four out of 1,548 boceprevir patients reported homicidal thoughts, compared with none in the control group.

Dr. Eliav Barr, a Merck vice president, said there was no evidence boceprevir increased those problems and said other factors could explain them. For example, intravenous drug use is a main route of transmission for hepatitis C and drug abusers have higher rates of psychiatric symptoms.‹