Vertex Pharmaceuticals's (Nasdaq: VRTX) lead drug candidate for hepatitis C infection has passed another test. The Cambridge, MA-based company, which has West Coast operations in San Diego, says today that it now has proof that its drug in combination with standard therapies can wipe out the chronic liver damaging disease about as well in 24 weeks as in 48 weeks.

This supplemental Phase III trial, "Illuminate," gave 540 patients who had never been treated before for their hepatitis C virus the experimental drug, telaprevir, in combination with standard treatments pegylated interferon and ribavirin. In the pool of patients who got the drugs for 24 weeks, the virus was wiped out in 92 percent of patients, while the disease was cured in 88 percent of patients in the 48-week trial arm. Those two pools of patients were those whose virus was not detected at weeks four and 12 of the study. The combination of drugs killed the virus in 72 percent of all patients in the trial. Nearly 7 percent of all patients in the study dropped out because of side effects of the treatment such as fatigue, itchy skin, and nausea. Other patients were either not cured with the telaprevir-based therapy or were put on only the standard treatments after taking telaprevir for 12 weeks. (Editor's note: This paragraph was augmented to provide additional details about the patient groups in the study.)

These data are expected to be part of the company's case to gain U.S. and European approval of telaprevir and begin sales next year. This study also follows and confirms the company's more important results in May from its first pivotal Phase III trial in which telaprevir in combination with traditional therapies wiped out hepatitis C infection in three out of four patients. The next big test for telaprevir will be the second pivotal study of the drug in patients whose disease could not be cured with traditional treatments. The results of that 650-person trial are due to be released in September.

It could be a big deal for patients with hepatitis C virus to be able to be cured of their illness in 24 weeks, or half the time they would take traditional therapies for the disease. The existing treatments often cause flu-like symptoms that make taking them an ordeal for patients, many of whom decide not to continue the drugs. "Patients who had a rapid response to telaprevir-based regimens at weeks four and 12 had a high likelihood of achieving a cure with 24 weeks of total treatment, which may provide important information to motivate people to continue therapy," Kenneth Sherman, a principal investigator in the study out of the University of Cincinnati College of Medicine, said in the Vertex release.

We'll see how Wall Street reacts to data from the Illuminate study today, since much of the results only confirm what was shown in the larger pivotal trial of more than 1,000 patients back in May.

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Ryan McBride is Xconomy's correspondent. You can reach him at rmcbride@xconomy.com, or follow him on Twitter at http://twitter.com/Ryan_McBride.

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