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Telaprevir Vertex hep C protease inhibitor drug works well in twice daily dosing
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Sat Oct 31, 2009 5:30pm EDT
* Twice daily telaprevir SVR rates of 82 pct and 83 pct
* Three times daily SVR rates of 81 pct and 85 pct
* 3 pct discontinuation rate due to rash
By Bill Berkrot
NEW YORK, Oct 31 (Reuters) - Vertex Pharmaceuticals Inc's (VRTX.O) closely watched hepatitis C drug telaprevir proved nearly equally effective in a twice daily regimen as three times a day, knocking out the virus in more than 80 percent of patients in both groups in a small study.
All previous Phase II studies of the highly promising experimental drug tested the medicine at three times a day dosing given at eight-hour intervals. This study hoped to show telaprevir could be administered twice a day 12 hours apart, which would be more convenient for patients.
Patients who received telaprevir twice a day in combination with the standard treatments of pegylated-interferon and ribavirin had a sustained viral response (SVR) of 82 percent in one arm and 83 percent in another, depending on which brand of interferon they received.
That compared with 81 percent and 85 percent of patients who were given telaprevir in the three times daily regimen, according to data to be presented at the American Association for the Study of Liver Diseases (AASLD) meeting in Boston.
The percentage of patients in whom the virus is undetectable 24 weeks after completing treatment yields the critical measure known as sustained viral response, or SVR, which is considered tantamount to a cure.
"SVR rates of 75 to 80 percent (in twice daily dosing) would be very well received by investors," Sanford Bernstein analyst Geoffrey Porges said prior to release of the data.
"I was expecting around 70 percent," Dr Patrick Marcellin, the study's lead investigator, said in an interview.
"This is the highest we have observed with this triple therapy and the major conclusion is that the rate of SVR is similar in those patients who received bid (twice daily) and those who received it three times daily," said Marcellin, a professor of medicine at the University of Paris and head of Viral Hepatitis Research Center in Hospital Beaujon.
Importantly, Marcellin noted, even though the telaprevir dose was higher in the twice daily regimen, there were "no new side effects, and that is very encouraging."
Investors may also be encouraged by the low 3 percent dropout rate due to serious rash, which had been a source of some concern in earlier studies. Just four of 161 patients discontinued treatment due to rash, with another three pulling out due to anemia.
Marcellin said doctors have learned how to manage the rash and are now less likely to discontinue treatment as a result.
The open label study tested treatment naive patients, or those who had not received prior treatment for the serious liver disease. Treatment duration depended on how quickly patients responded to the medicines, an approach known as response-guided therapy.
Patients who achieved rapid viral response, defined as undetectable levels of virus at week four, and who maintained undetectable levels through week 20, were able to stop all treatment after 24 weeks of therapy -- 12 weeks on the three- drug combination and 12 more of standard therapy.
They were then followed for six months post treatment to determine whether they achieved SVR.
Eighteen percent of patients in the study did not meet that rapid response criteria and received a total of 48 weeks of treatment with the standard drugs.
Three percent of patients in the study relapsed during post-treatment follow-up, the company said.
"This study confirms that 24 weeks can be used in the large majority of patients with with high efficacy. Shorter duration means less side effects and better quality of life," Marcellin said, noting that "tailoring treatments according to the very early response improves the management of the patient and the chance of the patient to be cured."
There has been high hope that telaprevir will allow for 24 weeks of treatment for many patients. The current drugs must be taken for 48 weeks and are often difficult to tolerate, with many patients suffering flu-like symptoms for the duration.
"Many of these patients are relatively young and very active, so to treat shorter is a real benefit," Marcellin said.
He cautioned that this was a small study and that much larger Phase III clinical trials must confirm the results.
But he added: "As a clinician for our patients, this is an important hope for the future. This is a big step in the history of the treatment hepatitis C." (Reporting by Bill Berkrot; editing by Andre Grenon))
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