In May 2011, the U.S. Food and Drug Administration (FDA) approved two new drugs to treat hepatitis C viral (HCV) infection. According to The New York Times, an estimated 3.2 million Americans have chronic HCV. Left untreated HCV can cause liver cancer, cirrhosis, end-stage liver disease and liver failure.
On May 13th the FDA approved Merck’s boceprevir under the brand name Victrelis™ and on May 23rd it approved Vertex Pharmaceutical’s telaprevir under the brand name Incivek™. Victrelis™ and Incivek™, the first new HCV therapies in 10 years, are protease inhibitors, a new class of drugs that thwarts the replication of viral enzymes.
The new drugs augment the current standard of treatment, which combines weekly injections of pegylated interferon (P-IFN) and a daily ribavirin (RBV) oral pill. Nearly 50% of patients do not respond to the current combination therapy alone. Even patients who do respond often experience debilitating side effects that can last the duration of the treatment—either 24 or 48 weeks. Interferon’s side effects include severe flulike symptoms, depression, fatigue and insomnia. Ribavirin can cause anemia, skin rash, fatigue and birth defects.
Both new therapies help boost the success of HCV treatment and protect the patient from the potentially severe and life-threatening impact of HCV symptoms. Success is measured by patients’ ability to “clear” the virus by achieving a sustained virological response (SVR) for at least six months after completing therapy. Though not technically a cure--HCV is often not completely eradicated from the liver--SVR is still the goal for clinicians. Lowering the viral load to undetectable levels in the bloodstream decreases the disease’s harmful effects.
In clinical trials in which Victrelis™ was used in combination with P-IFN/RBV, more than 60% of HCV patients achieved SVR vs. only 20-40% of patients on P-IFN/RBV alone. In clinical trials in which HCV patients received Incivek™ in combination with P-IFN/RBV, the SVR rate was 79%. This result signified an increase of as much as 45% when compared to patients receiving P-IFN/RBV alone. The promise of a shorter treatment cycle, 24 weeks for some patients on Incivek™ and 28 for some on Victrelis™ demonstrated in clinical trials, could also appeal to patients put off by the list of potential side effects.
One possible drawback of the new therapies is the number of daily pills that a patient must take to adhere to the treatment regimen. Victrelis™ is prescribed as 12 capsules a day--four pills, three times daily. RBV is prescribed as five or six pills daily or twice daily.
Another potential disadvantage of the new therapies is cost, which will undoubtedly balloon when the standard HCV regimen is combined with P-IFN/RBV. As it is, a cycle of P-IFN/RBV therapy could cost more than $30,000 according to The New York Times article published in July 010. A full round of therapy using Victrelis™ costs between $26,400 and $48,400; therapy with Incivek™ totals $49,200. Thus, patients on the combination therapy could see their HCV treatment costs more than double. Higher costs could become a challenge, particularly for those paying out-of-pocket. It should be noted that both Merck and Vertex offer patient assistance programs that provide free drugs to individuals who meet certain eligibility criteria, including income requirements. The companies may also assist with insurance co-payments.
“The availability of new therapies that significantly increase responses while potentially decreasing the overall duration of treatment is a major step forward in the battle against chronic hepatitis C infection,” said Edward Cox, MD, MPH, director, Office of Antimicrobial Products in FDA’s Center for Drug Evaluation and Research.
The approval of these drugs coincides with the issuing of a new recommendation concerning HCV therapies by the National Hemophilia Foundation’s (NHF) Medical and Scientific Advisory Council (MASAC). In it MASAC recommends patients with hemophilia and other bleeding disorders who choose these new therapies, particularly those already on anti-HIV treatment, undergo close monitoring. It also encourages providers and their patients to take into account possible safety considerations, including risk of bleeding, drug interactions and drug resistance. View and download MASAC Recommendations for Treatment of Chronic HCV Infection in Individuals with Hemophilia and Other Bleeding Disorders
Sources: The New York Times, May 13, 2011 and the Los Angeles Times, May 23, 2011