* Treatment combines VX-222, Incivek and 2 older drugs
* Half of patients on treatment rid of virus in 12 weeks
* Vertex shares fall 0.6 percent (Adds analyst comment, safety details, background, updates shares)
CHICAGO, July 26 (Reuters) - As many as half of hepatitis C patients in a small midstage trial who received a four-drug combination, including two Vertex Pharmaceuticals (VRTX.O) medicines, were able to stop treatment after just 12 weeks, according to interim results from the study.
Vertex on Tuesday released preliminary results of the trial, which added the company’s experimental oral drug VX-222 to its recently approved Incivek pill and the traditional standard treatments of pegylated interferon and ribaviron.
Interim results of the study, dubbed Zenith, showed that 50 percent of patients (15 of 30) who received the four-drug combination including 400 milligrams of VX-222, were able to stop all treatment at 12 weeks, and that 93 percent of those patients had undetectable virus 12 weeks after treatment ended.
Patients whose response did not make them eligible to halt treatment at 12 weeks, received the two older drugs for another 12 weeks. Of those who continued in the trial, all 13 appeared to be cured after 24 weeks of treatment, Vertex said.
“The patient numbers are relatively small in this study, and the results incomplete, but they are more encouraging than we would have expected,” Sanford Bernstein analyst Geoffrey Porges said in a research note.
However, Porges cautioned, “it is still too early to declare that VX-222 is a viable drug deserving of significant value in Vertex’s stock price today. The tolerability and safety will need to be established in much larger trials.”
About 130 million to 170 million people worldwide are chronically infected with hepatitis C virus, and more than 350,000 people die from hepatitis C-related liver diseases each year, according to the World Health Organization.
Incivek is widely forecast to become a multibillion-dollar seller and part of the new standard of care for the serious liver disease. It, and a similar new drug from Merck & Co (MRK.N) called Victrelis, are expected to transform treatment for millions of patients by significantly raising cure rates, while cutting the 48-week treatment regimen needed with the older drugs by as much as half for many patients.
Researchers and several companies are hoping that combination therapies with even newer drugs can further cut treatment duration since interferon often causes flu-like symptoms that leave patients feeling miserable.
With a combination that included 100 mg of VX-222 for 12 weeks, a sustained viral response was achieved by 82 percent of patients, or nine of 11.
“The results from this study are the first to show the potential for a combination of multiple direct-acting antiviral medicines to help people with hepatitis C clear the virus with as few as 12 and no more than 24 weeks of treatment,” Robert Kauffman, chief medical officer of Vertex, said in a statement.
Patients in the study had the most common and more difficult to treat genotype 1 form of the disease and had not received prior treatment.
VX-222 belongs to a class of drugs called polymerase inhibitors and works through a different mechanism than Incivek, a protease inhibitor that directly blocks an enzyme essential for viral replication.
The most common side effects from the four-drug regimen were fatigue, nausea, diarrhea, anemia, itchiness and rash. Six patients discontinued treatment because of adverse reactions.
JPMorgan analyst Geoff Meacham called the preliminary safety profile “encouraging,” noting no cases of kidney failure or severe diarrhea.
Vertex shares were down 28 cents, or 0.6 percent, at $49.17 in midday trading on the Nasdaq.
The company is due to report second-quarter results on Thursday, including the first few weeks of sales of Incivek, its first commercial product. (Reporting by Susan Kelly; additional reporting by Bill Berkrot in New York; Editing by Gerald E. McCormick, Derek Caney and Steve Orlofsky)