Ribavirin for treating Crimean Congo hemorrhagic fever—latest Cochrane review

In continuation of my update on Ribavirin

In a viral haemorrhagic disease where up to 40% of people developing it die, it is remarkable that doctors still do not agree whether the only recognised treatment, an antiviral drug called ribavirin, makes a difference. In a new Cochrane Review a team of authors at LSTM, along with colleagues in London, The Philippines and in Greece, evaluated the evidence to assess the effectiveness of treating Crimean Congo haemorrhagic fever (CCHF).

Crimean Congo haemorrhagic fever is spread by the bite of an infected tick, and is becoming more common, with outbreaks in Turkey, Eastern Europe and the Eastern Mediterranean. Doctors treat the infection in hospital with intravenous fluids, blood and good nursing care. The debates around ribavirinare common amongst clinicians treating the disease, with strong advocates on one side, and others who have policies not to use it, so the authors hoped the review would settle the debate.

The review authors found just one trial with 136 participants, and some observational comparative studies of 612 participants: overall the analysis did not provide a clear answer. When the authors examined studies that were often quoted as showing benefit, they were critically biased. Although fewer people died in groups receiving ribavirin, the apparent effect could be due to the drug, or equally because those getting the drug may have also been less sick, or received high quality nursing and medical care earlier in the disease.

Lead author, LSTM's Dr. Samuel Johnson, said: "Some doctors advocate giving ribavirin, and state that not to give it is even unethical. The problem is that the studies claiming to demonstrate benefit from the drug are designed in such a way we cannot separate the effect of the drug from other factors, and thus we do not know if ribavirin is effective at all."

The review clarifies the need for reliable research from a randomised control trial to establish whether ribavirin is effective. "The irony is that the strong beliefs and the widespread use of the drug may make it difficult to actually carry out the research needed" states Dr. Johnson. "What we need to know is whether it works, when it works, and how good it is."

But is there any harm in just giving it in case it works? Dr. Johnson points out, "Using unreliable research as evidence of benefit if it doesn't work could potentially waste resources and harm patients, we would also need to investigate other options. On the other hand, if ribavirin does work, then it needs to be rolled out to all patients who could benefit, which is currently not the case."

Whilst research into emerging infectious diseases and during outbreaks is difficult, the team hopes that the reviewprovides an opportunity to strengthen the call for greater steps to be taken to facilitate rigorous research providing reliable results in outbreaks of infectious diseases.

Ref : http://cochranelibrary-wiley.com/doi/10.1002/14651858.CD012713.pub2/abstract;jsessionid=9510BA3ECC4167F7B1CC8995CA6675B1.f03t03

New Anti-Viral Drug Shows Promise for Dramatic Improvement in Hepatitis C Treatment

Research team, led by Paul Kwo, M.D., of Indiana University School of Medicine, reported that adding the drug boceprevir, nearly doubled the treatment's effectiveness when given for 48 weeks in one treatment arm of the study. We knew that, Boceprevir (see structure) is a protease inhibitor being studied as a treatment for hepatitis C. It was being developed by Schering-Plough and has since been absorbed into the Merck's new pipeline since its acquired Schering in 2009. As of 2008, it is in phase II clinical trials (SPRINT-1 trial). Researchers claim that, adding a direct acting anti-viral drug to the standard treatment regimen for hepatitis C significantly increases the cure rate in the most difficult to treat patients.

Researchers claim that, the drug boceprevir increased the cure rate to as high as 75 percent in those who received 48 weeks of the three-drug combination therapy, compared to 38 percent of those in the control group, who received the standard two-drug treatment (peginterferon alfa-2b plus ribavirin)   for 48 weeks, said Dr. Kwo, associate professor of medicine at the IU School of Medicine. The two-year phase 2 trial was conducted at 67 sites with 520 patients in the US, Canada and Europe.

In the boceprevir study, known as the SPRINT-1 trial, researchers tested several different options to evaluate the effectiveness of the combination therapy.

"Both 28- and 48-week boceprevir regimens significantly increased sustained virologic response rates  which is the best definition of a cure we have  compared to the 48 week control," said Dr. Kwo. "The 48-week treatment arm with 4 weeks of peg interferon lead-in and 44 weeks of peg interferon, ribavirin, and boceprevir led to the largest improvement over the control group ever reported. That's very impressive." 

Researchers conclude that, best results were reported for the 103 patients who were treated for four weeks with the standard two drug regiment, followed by 44 weeks of the three-drug regimen including boceprevir: 75 percent of these patients tested negative for evidence of the virus six months after the end of treatment.

As per the lead researcher, Dr. Kwo, based on this phase 2 study, it appears that if this drug receives final approval approximately two-thirds of patients will be able to be treated successfully with 28 weeks of treatment and one-third will need 48 weeks of treatment, though this will require confirmation from the phase 3 trials, from which preliminary results were recently released.

Ref  : http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2810%2960934-8/fulltext