Cure for hepatitis C gets closer

About 170 million people worldwide are estimated to have been infected with Hepatitis C.

Among them, many celebrities including: actor  Larry Hagman; Rolling Stone Keith Richards; American Idol judge Steven Tyler; Baywatch babe Pamela Anderson; stuntman Evel Knievel and “Dr Death” Jack Kevorkian.

Currently there is no cure for this bloodborne, liver destroying virus and until recently there has been no specific treatment. Although interferon injections have been used, the  flu-like symptoms and other side effects often lead patients to discontinue or delay treatment.

However, in the last two years, two new injectable treatments were approved for use and clinical trials of oral medicines demonstrate promising results.

Earlier this month Abbott Laboratories released impressive data from a small mid-stage trial combining its experimental protease inhibitor ABT-450 boosted by the antiviral drug ritonavir, along with a polymerase inhibitor and ribavirin. The combination achieved a 95% cure rate in one arm of the study.

Separately, Gilead reported results from the Electron study, showing that of 88% of the 25 patients who completed 12 weeks of treatment with GS-7977 and ribavirin, had undetectable levels of virus four weeks after completion of treatment.

And last Thursday, at a liver disease meeting in Europe, researchers released interim data showing that a combination regimen of  GS-7977 from Gilead Sciences Inc and daclatasvir  from Bristol-Myers Squibb Co led to a 100% response rate in previously untreated patients with the most common form of hepatitis C.

GS-7977 is a nucleotide polymerase inhibitor. Daclatasvir  is from a new class of drugs known as NS5A inhibitors. Both are designed to block enzymes essential to replication of the hepatitis C virus.

All 44 of the patients who had the most common and difficult to treat type of hepatitis C (Genotype 1)  had undetectable levels of the virus in their blood four weeks after completing treatment, while 40 out of 44 patients with Genotypes 2 or 3 had undetectable levels of virus at four weeks following treatment -a 91% response rate.

The experimental drugs were considered to be well tolerated with the most frequent side effects being fatigue, headache and nausea. Full results from the trial are expected later this year.

Despite these promising results the 2 companies have decided not to pursue a collaboration.  Gilead is now commencing a trial of GS- 7977 in combination with its own experimental NS5A inhibitor, while Bristol-Myers is testing its drug daclatasvir with a compound similar to GS-7977.

The race for a cure seems to be well and truly on…and whoever comes first the real winners will be the people already infected.