BOSTON -- Research abstracts of data set for unveiling at next month's big hepatitis C meeting were published over the weekend, offering another glimpse at experimental drugs from Vertex Pharmaceuticals ( VRTX) and Gilead Sciences ( GILD), among others.

The Liver Meeting, sponsored by the American Association for the Study of Liver Diseases, is the biggest gathering of liver disease experts and researchers in the U.S. This year's event, Nov. 2-6 in Boston, will be the focus of investors and analysts interested in the development of new, potentially blockbuster, drugs for the treatment of hepatitis C.

The October issue of the AASLD medical journal Hepatology was made available to association members last weekend and contained detailed data abstracts ahead of next month's meeting. Some of these abstracts contain new, albeit limited, information about a slew of hepatitis C drugs.

The really important data, however, won't be publicly disclosed until the meeting begins.

But for those hepatitis C junkies who can't wait a month, here's a quick summary of some of the research abstracts. Full public access to the abstracts should be available starting Tuesday and can be found here:


I've written extensively about Vertex and its hepatitis C drug telaprevir, a protease inhibitor that, so far, has shown very promising direct antiviral activity against the hepatitis C virus. (For that background, look here and here.)

The Liver Meeting is a big event for Vertex because for the first time, researchers will be presenting phase II data from a U.S. study detailing rates of sustained virologic response (SVR) for hepatitis C patients taking telaprevir-containing regimens.

In layman's terms, SVR is a cure for hepatitis C, so the data will provide the most important measure of the drug's efficacy and safety to date.

As I wrote last week, investor expectations for the telaprevir SVR rate in the U.S-based phase II trial, known as Prove 1, are in the low-60% range.

There isn't any new information in the abstracts that shed light on the Prove 1 study, but there is some new data from the European-based phase II study known as Prove 2.

Specifically, 79% of patients taking a telaprevir-containing regimen in Prove 2 reported having an undetectable level of virus after 12 weeks.

That compares to a 12-week undetectable rate of 70% in the Prove 1 study. It's expected that the efficacy data from Prove 2 will be a bit better than Prove 1. Historically, European hepatitis C patients perform better than their U.S. counterparts.


The Liver Meeting will be the clinical debut for Gilead's experimental polymerase inhibitor GS 9190, the company's first big push into the hepatitis C market.

A single-dose study of GS 9190 shows a median viral load reduction of 0.5 to 1.5 log, depending on the dosage, according to the abstract. (Generally speaking, viral load changes are measured in "log" -- a log 1 reduction is considered a good level of efficacy at this stage of development.)

That's a respectable showing of efficacy for a single dose. There were also no unusual or worrisome toxicities detailed in the abstract.

The second part of this phase I study is more important and will dose patients over eight days. Data from this portion of the study will be presented at the meeting.


Swiss drug maker Roche has garnered some attention for its polymerase inhibitor RS 1626, which in previous studies has shown very good efficacy. There are, however, some worries about the drug's toxic effects, which include anemia.

Roche will present some early data next month on RS 1626 used in various combinations with standard-of-care drugs pegylated interferon and ribavirin. Some of this data is contained in the abstract, and it's quite interesting.

A 1,500-milligram dose of RS 1626 plus standard of care resulted in 81% of patients reporting undetectable levels of virus after four weeks. By comparison, only 5% of patients given the standard of care alone had undetectable virus levels.

There were some serious adverse events reported in the abstract, including grade 4 neutropenia, or low white blood cell counts. The rates of toxicity increase with higher doses of RS 1626. There is no mention of anemia in the abstract, although that could be reported at the meeting.


Last month, Pharmasset ( VRUS) released positive preliminary results from a phase I study of its polymerase inhibitor R7128 when dosed by itself for 14 days in patients with hepatitis C. The best data was from a 1500-mg dose of R7128 given twice a day, which resulted in a 2.7 log reduction of viral load.

Pharmasset and its partner Roche have already announced plans for new phase II studies of R7128 in combination with standard of care. Additional data from the phase I study will be presented at the meeting.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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