CD, a 50-year old male that was recently admitted to the hospital for pain in his right upper abdomen, jaundice, and fever. While hospitalized it was discovered CD is positive for hepatitis C. As an ambulatory care pharmacist, CD is referred to your clinic for treatment. His laboratory results from the clinic are listed below.

Past medical history:

Intravenous drug misuse

Labs/Vitals:

Ht: 5’10"

Wt: 168 lbs

BP: 141/76 mmHg

HR: 82 BPM

Temp: 98.6 F

AST: 100 U/L (<34 U/L)

ALT: 83 U/L (10-49 U/L)

Alkaline phosphatase: 147 U/L (46-116 U/L)

Albumin 4.3 g/dL (3.2-4.8 g/dL)

Hepatitis C:

Antibody: Positive

Antigen: Positive

You are going to initiate treatment with Mavyret. What important lab test should be ordered before initiating treatment for CD’s hepatitis C?

A. Hepatitis C genotyping

B. Latent tuberculosis testing

C. Toxicology screen for alcohol and illicit medications

D. Hepatitis B surface antigen and antibody testing

Answer with rationale:

Hepatitis C (HCV) is a viral infection affecting the liver and is most commonly transmitted through blood-to-blood contact, such as contamination from needle sharing for intravenous drug use. A less common way to contract HCV is through sexual contact or vertical transmission at birth. People living with HCV can remain asymptomatic for years but over time develop chronic conditions such as hepatic disease, cirrhosis, or cancer if untreated. The development of direct-acting antiviral (DAA) medications has now made it possible to cure HCV with a success rate of 95% for most patients within 8–12 weeks of therapy. DAAs function by inhibiting the ability of HCV to replicate inside the body.

Let's go through each answer and reveal rationale for why each answer is right or wrong.

Answer A is incorrect. While helpful to have additional patient specific information, genotyping is no longer a requirement for HCV patients. Newer drug therapy options such as sofosbuvir/velpatasvir and glecaprevir/pibrentasvir are effective at treating all 6 of the major HCV genotypes. Genotyping is an option to be considered when patients experience DAA treatment failure.

Answer B is incorrect. Tuberculosis is a common pathogen among immunocompromised patients. In addition, a number of immunosuppressive medications used for autoimmune diseases require testing to ensure latent tuberculosis is not present. Receipt of immunosuppressive medications (e.g. infliximab) could result in activation of tuberculosis. However, initiation of Mavyret would not require initial tuberculosis screening. 

Answer C is incorrect. Treatment duration for patient’s undergoing DAA drug therapy usually lasts a short duration between 8-12 weeks. DAA drugs have been proven to be effective even in patients with an active or recent substance misuse disorder. These patient’s may be at a higher risk for reinfection but should not be disqualified as treatment candidates.

Answer D is correct. DAA medications that are used to treat HCV carry an increased risk of hepatitis B virus (HBV) reactivation in patients co-infected with HCV and HBV. Before initiating treatment in patients positive for HCV, HBV screening should be conducted and ruled out. This is a boxed warning for both Mavyret and Epclusa. 

Brand/generics Covered: sofosbuvir/velpatasvir (Epclusa), glecaprevir/pibrentasvir (Mavyret)

Naplex Competencies Covered:

1. A. 5 – Safety and effectiveness (eg, laboratory parameters, vital signs)

3.B - Health histories, screenings, and assessments

3.C. 2 – Interactions (eg, drug-drug, drug-condition, drug-food, drug-allergy, drug-laboratory)