CIENCIASMEDICASNEWS: NIDA Research Seeks to Reduce Viral Hepatitis Caused by Drug Use Behaviors

jueves, 30 de mayo de 2013

NIDA Research Seeks to Reduce Viral Hepatitis Caused by Drug Use Behaviors

May 30, 2013 • 0 comments • By Wilson Compton, M.D., M.P.E., Director, Division of Epidemiology, Services and Prevention Research, National Institute on Drug Abuse, National Institutes of Health and Jag Khalsa, Ph.D., Chief, Medical Consequences of Drug Abuse and Co-occurring Infections Branch, Division of Pharmacotherapies and Medical Consequences of Drug Abuse, National Institute on Drug Abuse, National Institutes of Health

Wilson Compton, MD, MPE, and Jag Khalsa, PhD

Hepatitis C virus (HCV) is the leading cause of liver failure and liver transplantation in the United States and people who inject drugs (PWID) are particularly susceptible to this disease with as many as 70% or more of this population testing positive for the virus. To make matters worse, PWID enjoy little if any consistent health care and are largely unaware of their HCV infection status. Those who are successful in accessing healthcare and are diagnosed with hepatitis C are rarely offered antiviral treatment. If they are offered HCV treatment, they often face additional treatment challenges since many suffer from mental disorders and/or HIV in addition to HCV and drug addiction. To address these challenges, the National Institute on Drug Abuse (NIDA) is investing in research to break down the barriers PWID confront when accessing HCV screening, treatment, and prevention services. This research is contributing to government-wide efforts to implement the Action Plan for the Prevention Care and Treatment of Viral Hepatitis, which sets forth among its six priorities “Reducing Viral Hepatitis Caused by Drug Use Behaviors.”

Screening Research

PWID are extremely likely to be HCV-positive, yet many do not know they are infected. Unfortunately, free or low cost HCV testing is not widely available in the same way that HIV and STI testing is. While rapid HIV tests are available and have been shown to increase receipt of HIV test results among PWID, there is no comparable research available yet for rapid HCV testing among PWID. (Rapid HCV tests were FDA approved and became available in 2010.) Studies using rapid HCV testing in outreach with PWID are currently being developed and implemented. NIDA-supported research is also assessing the accuracy and acceptability of rapid HCV tests in point-of-care clinics to more promptly identify PWID that are infected and link them to the care they need.

Treatment Research

HCV testing is only the first step. Once patients test positive, they need to get into care in order to access HCV treatment—often PWID need care not just for their HCV but also for multiple, concurrent health conditions. However, many physicians are unwilling to treat patients who are actively using drugs despite data that show injection drug use has little bearing on HCV treatment adherence.¹ NIDA-supported research is examining coordinated care models that utilize case managers to integrate HCV specialty care with primary care, substance abuse treatment and mental health services from multiple, geographically separate providers to provide these patients with treatment regimens that address all of their health needs. NIDA also continues to study ways to improve HCV treatment. Until recently, only two antiviral medications (peginterferon and ribavirin) were available to treat HCV infection. Although both are effective, some patients experience serious adverse effects including depression and suicidal thoughts. New direct acting antiviral medications, which first became available in 2011, have improved treatment outcomes, and more are in development. NIDA plans to test these new agents further in drug abusing populations. Also recently, researchers have identified genes that explain why some people who are HCV-positive are able to clear the virus without medication.² These genes also enable people who are unable to clear HCV on their own to respond more favorably to treatment medications. To be sure, more studies must be done, but this is a good step toward personalized medicine for the treatment of HCV.³

Prevention Research

While HCV treatment is important, prevention is key to ending the scourge of HCV. The estimated rate of new HCV infections has decreased since the peak in the early 1990s in part because the blood supply began being screened and in part because of prevention efforts with PWIDs focused on reducing new HIV infections. Like HIV, hepatitis C is also transmitted through blood exposure; however, due to differences in the viruses, HCV is able to last longer outside of the body than HIV. Epidemiologic evidence of ongoing HCV transmission among PWIDs suggests that additional prevention strategies are needed to curb the epidemic of HCV. Toward that end, NIDA also supports research on the behavioral aspects of HCV risk and transmission among young PWIDs. Other NIDA research is exploring how expanded HCV treatment can prevent further transmission of HCV and HCV/HIV co-infection, building on the successful “treatment as prevention” model developed for HIV.⁴ The goal is to reduce the viral load within this population by successfully treating HCV infection, thereby preventing further spread of this blood-borne infection within the community.
NIDA is committed to reducing the stigma associated with drug use and developing evidence-based treatment and prevention strategies for those who suffer from addiction and other health consequences that result from drug use, including viral hepatitis. It is our belief that with a concerted, multifaceted approach to HCV screening, treatment, and prevention, the goals of the Action Plan can be achieved for all those at risk of or living with viral hepatitis.
Read more at NIDA’s new webpage, Viral Hepatitis—A Very Real Consequence of Substance Use.

[1] Grebely, J., et al., Factors associated with uptake of treatment for recent hepatitis C virus infection in a predominantly injecting drug user cohort: The ATAHC Study. Drug Alcohol Depend, 2010. 107(2-3): p. 244-9.

[2] Duggal, P., et al., Genome-wide association study of spontaneous resolution of hepatitis C virus infection: data from multiple cohorts. Ann Intern Med, 2013. 158(4): p. 235-45.

[3] Bruce, R.D., et al., A review of pharmacological interactions between HIV or hepatitis C virus medications and opioid agonist therapy: implications and management for clinical practice. Expert Rev Clin Pharmacol, 2013. 6(3): p. 249-69.

[4] Cohen, M.S., et al., Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med, 2011. 365(6): p. 493-505.