The hepatitis C virus (HCV) can go years without creating symptoms, leading many people to not suspect they have it and not seek testing. While around 20% of infected individuals will not even require treatment and spontaneously get rid of the virus, others are at risk for scarring and cirrhosis of the liver that may ultimately lead to a transplant. The chances of this happening increase as the disease is given time to progress. Some current treatment options for HCV can last 11 months with undesirable side effects, but new medications that may gain approval from the Food and Drug Administration (FDA) can clear a patient of HCV in as little as 12 weeks.
There are several genotypes of HCV that require different treatments. Genotype 4, for example, is currently treated for 48 weeks with a combination of pegylated interferon and ribavirin. The side effects can be widespread and may include depression, chest pain, anemia, and alopecia. Ribavirin boosts peginterferon’s efficacy, though how it does this isn’t well understood. In concert, these two drugs boost the patient’s immune system to better fight the virus, with a 70% success rate for driving the virus down to undetectable levels. The drugs are also administered via injections or multiple pills in a day. The new medications being introduced are taken orally one daily and are effective against multiple genotypes of HCV.
Sofosbuvir, a medication manufactured by Gilead Sciences, has shown incredible potential. During phase 2 trials, the drug was enormously effective when combined with the traditional peginterferon-ribavirin combination. Out of the 327 patients representing four different genotypes of HCV, 90% were cleared of the virus in only 3 months. A second trial that used ribavirin without the side effect-inducing peginterferon had a 67% success rate average, but 97% of those with genotype 2 were cleared at 12 weeks.
When simeprevir, a new drug from Johnson & Johnson, was combined with sofosbuvir-ribavirin in a phase 2 trial, 80% of patients were cured of the virus. Even with this success, Johnson & Johnson and Gilead have no plans to work together for a phase 3 trial. Bristol-Myers Squibb also will not work with Gilead for a trial of their new drug daclatasvir, despite curing 100% of the 41 patients in phase 2 when paired with sofosbuvir. This could be because BMS developed a second drug, asunaprevir, that worked with daclatasvir to cure 85% of trial participants.
Last month, the FDA submitted simeprevir and sofosbuvir for approval, which they are expected to receive in 2014. It is unclear if they will be approved together or as independent drugs. If approved separately, many doctors may prescribe the combination “off label” anyway, though some insurance companies may not approve the use of two separate direct-acting antivirals. This will make the treatment more expensive for those who will have to pay out of pocket, but might be worth it for patients who have not responded to other treatments. Unfortunately, the HCV drugs are quite expensive and since the cure happens relatively quickly, it eliminates the mass production capabilities that would drive down the price.
While the potency of these new medications could potentially rid the world of HCV, the price and the fact that so many carriers do not even know they are infected greatly hinders that progress. As such, many researchers are making considerable effort toward a HCV vaccine.