In a Meet-the-Professors session at ID Week 2018, experts addressed strategies to check for drug-drug interactions, direct-acting antivirals for special populations, and the management of hepatitis C virus infection for persons who inject drugs.
A meet-the-professor session at the 2018 ID Week Annual Meeting in San Francisco, CA, covered a wide swath by providing an overview of updated recommendations on testing for hepatitis C virus infection, strategies to check for drug-drug interactions (DDIs)—summarizing DDIs of particular concern for direct-acting antivirals (DAAs)—DAAs that are applicable for special populations (such as patients with renal impairment or those with decompensated cirrhosis), and the management of hepatitis C virus infection for persons who inject drugs (PWID).
The 4 cases that were discussed highlighted the challenges clinicians face in terms of heterogeneity in symptoms, risk factors, treatment compliance, and treatment affordability. The consensus is that it is definitely not a one-size-fits-all landscape.
Testing for hepatitis C virus infection can be based on the risk of exposure. A partial list of the risks includes current or former injection drug use, certain medical conditions, blood transfusion, and organ transplantation. Individuals exposed to hepatitis C virus-positive blood and children born to hepatitis C virus-positive women should definitely be tested.
The US Centers for Disease Control and Prevention (CDC) recommendations are adamant when it comes to pregnancy. “Testing during pregnancy is not recommended due to the lack of safety and efficacy data,” said Kristen Marks, MD, during the session. In a later interview with MD Magazine®, Marks added that “the [Infectious Diseases Society of American and American Association for the Study of Liver Diseases] recommendations do recommend testing because of the shift we have seen in the demographics (younger people with hepatitis C virus infection) in addition to the benefits in terms of testing the infant.”
“Since we lack adequate data for treating [hepatitis C virus] in pregnancy, the mother should not be treated until after the pregnancy. And, then it can reduce transmission risk next pregnancy. I’m hopeful the CDC will come around to recommending testing in pregnancy as well,” she added.
In an era of increasing injection drug use, the age pattern of hepatitis C virus infection has shifted downward. Only a decade ago, the prime ages for infection were those 40 to 50 years for both men and women. Now, cases are burgeoning in men and women 20 to 30 years of age. This pattern is especially distressing in women, since the prevalence of hepatitis C virus infection among pregnant women who are opioid users is high and hepatitis C virus screening in infants is not a perfect science.
John Scott, MD, MSc, from the University of Washington, Seattle, discussed DDIs. Lest a clinician think that reading the product description is a sufficient guide to avoiding interactions with currently prescribed drugs, Dr. Scott used the example of primidone, which has interactions that are not detailed in the product literature. “Always check at least 2 different sources for information on drug-drug interactions. An especially good source is the database maintained at the University of Liverpool,” he said.
There are a raft of DDIs that can occur for the various combinations of sofosbuvir, velpatasir, voxilaprevir, ledipasvir, glecaprevir, and pibrentasir used in hepatitis C virus treatment. Statins can also pose a concern. “With sofosbuvir/ledipasvir, sofosbuvir/velpatasir, and glecaprevir/pibrentasir, statin-induced myopathy is a risk. Talk to the prescribing clinician to see if the statin is really needed or if it can be withheld for a period of time or if the dose can be reduced,” commented Dr. Scott in the session.
Knowing what treatment combinations are detrimentally affected by other medications that the patient might be taking at the same time is essential. For example, the action of glecaprevir can be reduced by the proton pump inhibitor omeprazole, but as long as the dose does not exceed 40 mg, then the change is not a concern. In addition, antacids are not a concern; however, both proton pump inhibitors and antacids can reduce sofosbuvir activity to a level that is a concern. Taking sofosbuvir/velpatasvir 4 hours prior to proton pump inhibitors or antacids is prudent.
For patients infected with hepatitis C virus who are also positive for HIV, treatment is no longer a vexing issue, according to Dr. Scott. “Antiretroviral therapy does not have to be interrupted for DAA therapy of hepatitis C virus infection. For the most part, [clinicians can] use the same dosing and length of therapy.1 The exception is sofosbuvir/ledipasvir, which should be used for 12 weeks, regardless of baseline viral load,” he advised.
Other guidance included the use of glecaprevir/pibrentasir or elbasvir/grazoprevir for patients with advanced chronic kidney disease and the avoidance of hepatitis C virus protease inhibitors in class B or C cirrhotic patients.
The final topic was hepatitis C virus treatment for PWID. The view that hepatitis C virus treatment is fruitless for injection drug users should fall by the wayside, according to Dr. Marks. In recent trials, hepatitis C virus treatment was successful in patients who were concurrently receiving opiate agonist therapy,2 even if treatment was interrupted for up to 7 consecutive days.3 Although such treatment interruptions are not welcome, it is heartening to know that an interruption may not rule out treatment success, at least for some people.
“Hepatitis C virus treatments are compatible with other drugs of abuse, including cannabis, cocaine, diamorphine, gamma-hydroxybutyrate, ketamine, ecstasy, methamphetamines, and phencyclidine,” shared Dr. Marks, adding that “treatment environments that can provide multi-disciplinary services around addiction, social support, mental health, and re-infection prevention will be essential.”
Kristen Marks, MD, MS: Grants from Gilead Sciences paid to Weill Cornell
John Scott, MD, MSc: Data adjudication for canakinumab (Novartis)
Kristen Marks, MD, MS, Weill Cornell Medicine, New York City, New York; John Scott, MD, MSc, University of Washington, Seattle.
Session 98. Meet-the-Professor Session. Hepatitis C: Case-Based Discussion of HCV Treatment in the DAA Era.
Brian Hoyle, PhD, is a medical and science writer and editor from Halifax, Nova Scotia, Canada. He has been a full-time freelance writer/editor for over 15 years. Prior to that, he was a research microbiologist and lab manager of a provincial government water testing lab. He can be reached at firstname.lastname@example.org.