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.

Interfering Interferon

Word on Health heard some news this week that might just help asthma patients breathe easier.

Researchers at UT Southwestern Medical Center have found that interferon, a drug used to treat a variety of cancers such as leukemia and melanoma as well as multiple sclerosis and hepatitis; can block the development of certain immune cells known to cause asthma.

Known as T-helper 2 cells, under normal circumstances, they help protect against infections by releasing chemicals that induce inflammation. However in some people, these cells can promote allergic responses to normally harmless substances, including animal dander, pollens, and pollutants. Once Th2 cells become reactive to these substances, they promote all of the inflammatory processes common to allergic diseases like asthma and eczema.

The results which have just been published in the Journal of Immunology, suggest that interferon might be a viable, therapy for the treatment of asthma.

Dr. J. David Farrar (right) and research assistant Jonathan Huber

This finding is incredibly important, because humans are being treated with interferon for a variety of diseases, yet no one has tried treating asthma patients with interferon,” said J. David Farrar, PhD, Assistant Professor of Immunology and Molecular Biology at UT Southwestern and lead author of the study. “The current therapies for asthma are inhalers and steroids, both of which offer only temporary relief.”

In the current study, the researchers showed that interferon blocks the development of developing Th2 cells by targeting the very transcription factor that regulates their development and stability in the first place.

According to Farrar, “If you can stop a Th2 cell from ever developing, and if you can take a Th2 cell that has already become one and stop it from secreting these asthma-causing chemicals, then that’s really the ‘Holy Grail’ of treating asthma.”

Could this be an end to inhalers?  Only time and clinical trials will tell.