Pharmasset Hep C Data Wows Investors (EASL March/April 2011)
By Adam Feuerstein 03/08/11 - 11:46 AM EST|
PRINCETON, N.J. (TheStreet) -- Pharmasset(VRUS_) shares are soaring on the release of new but very preliminary data that hints at a breakthrough, all-oral cure for hepatitis C.
Treatment with two oral drugs developed by Pharmasset resulted in 15 of 16, or 94%, of patients reporting undetectable levels of the hepatitis C virus after 14 days, according to interim results from a study released Monday.
These early data on the two Pharmasset drugs -- PSI-938 and PSI-7977 are the best reported to date by any company seeking to develop a new, all-oral therapy for hepatitis C. This Pharmasset effort is drawing even more attention because it potentially eliminates the need for patients to be treated with long-acting interferon, one of two drugs currently used to treat hepatitis C but which is difficult for patients to tolerate and causes many side effects
Pharmasset shares rose 24% on Monday and were up another 8% to $66.92 on Tuesday.
The PSI-938 and PSI-7977 combination data were released Monday in a research abstract released online by the European Association for the Study of the Liver (EASL), which holds its annual meeting March 30 through April 3.
EASL makes research abstracts for its annual meeting freely available to the public but prohibits journalists from writing about the data contained in the research abstracts until they are presented at the annual meeting. TheStreet refuses to adhere to EASL's media embargo since these hepatitis C data are freely available online now and are impacting the stock prices of publicly traded companies developing hepatitis C drugs.
While investors are displaying great enthusiasm for the Pharmasset all-oral drug combination, the data from the study are very early. One particular risk seen in other, similar studies that omit long-acting interferon is the development of mutated hepatitis C virus that can quickly become resistant to drug treatment.
None of the patients treated in the Pharmasset study have reported rebounding levels of hepatitis C virus, according to the research abstract, but so-called viral rebound may emerge as patients are treated longer, or when treatment is stopped and these patients are followed long-term to determine if they are truly cured.
Hep C Update: Vertex, Merck and Gilead
Hep C drug updates from this weekend's closely watched liver disease meeting.
By Adam Feuerstein, TheStreet.com Senior Columnist
THESTREET.COM - 10/31/10
BOSTON (TheStreet) -- Updates on hepatitis C stocks from a weekend at the American Association for the Study of Liver Disease (AASLD) annual meeting:
Vertex Pharmaceuticals (Symbol : VRTX): Telaprevir was the superior hepatitis C drug coming into AASLD and no data or information released over the weekend, including from Merck and its competing drug boceprevir, changed that view.
If there's a debate left to have about telaprevir vs. boceprevir in hepatitis C, it's forecasting the market share each drug may garner once both are approved next year. Right now, the Street's consensus is overwhelmingly in favor of telaprevir (roughly 70-80%) to boceprevir's (20-30%). Analysts expect telaprevir sales in the range of $2.5 billion by the end of 2014.
Whether those estimate and market share splits change significantly or not could depend on feedback analysts and investors get from Hep C doctors attending AASLD after they get a chance to see full data presentations from the phase III studies of each drug Monday and Tuesday.
While we wait for those presentations, Vertex did issue a press release Saturday updating results from the two, previously announced phase III studies in treatment-naive hepatitis C patients.
As a reminder, in the phase III "Advance" study, 75% of patients treated with telaprevir plus the standard of care (long-acting interferon plus ribavirin) achieved a sustained viral response, which is essentially a cure. That compares to 44% of patients treated with standard of care alone. A second phase III study dubbed "Illuminate" confirmed that patients who respond well to telaprevir can be treated and cured in six months, half the time it normally takes to treat Hep C.
New data from the Advance study showed that 62% of African-Americans/Blacks were cured after treatment with telaprevir compared to 25% of African-American/Blacks treated with standard of care alone. This is significant because, historically, African American hepatitis C patients respond poorly to standard therapy.
Also from the Advance study, 62% of people with advance liver fibrosis or cirrhosis achieved a cure with telaprevir compared to 33% of similar patients treated with standard therapy.
Vertex also disclosed that 58% of telaprevir-treated patients in the Advance study and 65% of patients in the Illuminate study were able to cut total treatment time to 24 weeks from the 48 weeks of therapy normally needed to achieve a cure.
Merck: A press release Saturday updating results from two phase III studies of boceprevir contained a dizzying array of statistics but the overall profile of the drug -- not quite as good as telaprevir -- didn't change much.
Researchers are presenting the boceprevir data on Monday and Tuesday, which will hopefully shed light on why the analysis summarized in the Merck press release appears to exclude certain patients.
Boceprevir's overall cure rate for treatment-naive Hep C patients ranged from 63-66%, with the proportion of patients eligible for shortened therapy 44%. The cure rate was high (87% for African-American/Blacks and 97% for non-African Americans) for those patients that did receive shortened therapy due to an early and robust response to boceprevir.
Merck is also presenting data at AASLD from a study of boceprevir in patients who were not cured by previous treatments. When these "treatment resistant" patients were re-treated with boceprevir, cure rates ranged from 59% to 66% compared to 21% of patients re-treated with just standard of care.
Vertex has data on telaprevir in similar hard-to-treat patients that is superior to boceprevir, with cure rates of 65% overall that included patients much more resistant to therapy than those enrolled in Merck's boceprevir study. When similar treatment-resistant patients are compared across both studies, boceprevir's 66% cure rate falls short of telaprevir's 78% cure rate.
Vertex is not presenting its telaprevir data in treatment resistant patients at this year's AASLD meeting.
Gilead Sciences (Symbol : GILD): The HIV drug powerhouse should be a major player in developing new Hep C therapies because the viral diseases share similar traits. Yet Gilead has fumbled early Hep C drug development efforts, forcing the company to rethink strategy as competitors surged ahead.
In June, Gilead lured Duke University's Dr. John McHutchison, a leading Hep C researcher, to join the company and take over its R&D push into liver disease. On Saturday night, Gilead held a coming-out party for McHutchison, who gave investors a detailed look at the company's revamped Hep C drug development efforts.
Companies like Vertex are early winners for combining powerful, new oral drugs like telaprevir to the standard of care in Hep C -- injectable interferons and oral ribavirin. Gilead isn't trying to compete here; instead the company is taking a page from its HIV playbook, believing that the long-term future of Hep C treatment will be in developing combination of oral drugs --each acting against the Hep C virus in different ways -- that can eliminate the need for injectable interferon and perhaps even ribavirin, both of which can cause nasty side effects.
Just like Gilead sells a Atripla for HIV treatment -- a single, daily pill that combines three different medicines -- the company would like to one day develop a single, multi-drug pill for Hep C, said McHutchison.
At this year's AASLD, an early, 28-day study combining two oral drugs from Gilead's labs didn't yield promising results, but when those same drugs were combined with either ribavirin alone or in a quadruple combination wth ribavirin and interferon, the antiviral response was much more robust. In the quad combination, 93% of patients had undetectable viral levels after 28 days.
Saturday night, Gilead executives were honest about not knowing which, if any, of the oral drug combinations under development will eventually work. Gilead, however, will have seven experimental Hep C drugs that attack the virus in six different ways in human testing by next year.
That's an impressively deep and broad pipeline of Hep C drugs, which is reason for optimism even in the early days of testing.
Johnson & Johnson (Symbol : JNJ): In addition to partnering with Vertex on telaprevir, J&J is developing its own Hep C drugs, including TMC435. A phase IIb study being presented Monday shows that between 79% and 86% of patients treated with TMC435 and standard of care responded well enough to stop all therapy after 24 weeks.
This interim result for TMC435 looks better than the 58% and 65% of telaprevir-treated patients who were able to stop therapy after 24 weeks, except that J&J used a more liberal definition of response, which inflates its numbers.
Patient treated with higher doses of TMC435 also reported increases in certain liver enzymes levels, raising safety concerns about the drug.
Idenix Pharmaceuticals (Symbol : IDIX): IDX184 on its own doesn't appear to be the reason for the FDA clinical hold that temporarily shut down studies of IDX184 and IDX320 in September, according to safety data presented Sunday. No serious elevations in liver enzymes were observed in a study of IDX184 plus standard of care, which led the presenter to hypothesize that the problem is eitherwith IDX320 alone or the combination of the two drugs.
Pharmasset (Symbol : VRUS): The jury is still out on the optimal treatment duration for RG7128, which is partnered with Roche (Symbol : RHHVF).
Eighty-eight percent of patients responded to 12 weeks of treatment with a 1,000 mg, twice-daily dose of RG7128 plus standard of care compared to 49% of patients treated with standard of care alone, according to interim data presented Sunday.
Roche (Symbol : RHHVF) and Pharmasset (Symbol : VRUS) are conducting another study of RG7128 looking at 24 weeks of dosing.
Merck: Vaniprevir posted impressive cure rates ranging from 61-84% after four weeks of dosing followed by standard of care, but the results are likely skewed by small numbers of patients. A larger study of vaniprevir in treatment-resistant patients is underway.
--Written by Adam Feuerstein in Boston.