Utilization of Antivirals to Combat Influenza

PTCE would like to acknowledge Genentech, a member of The Roche Group for their generous support of pharmacist education.

Influenza treatment with antivirals was presented during a virtual symposium held in conjunction with the first virtual ASHP Midyear Clinical Meeting and Exhibition. Two speakers, Elias B. Chahine, PharmD, FCCP, FASCP, FFSHP, BCPS, BCIDP, and Allana J. Sucher, PharmD, BCPS, BCIDP, presented an in-depth overview of influenza in a satellite symposium titled “Chemoprophylaxis and Treatment of the Influenza Virus: The Expanding Role of Novel Antivirals in High-Risk Patient Populations.” The session focused on available antivirals for its treatment, recommendations for high-risk patients, and the role of the pharmacist.

Dr Chahine began the presentation by reviewing the annual impact of the influenza illness. He went on to examine the etiology, pathophysiology, modes of transmission, and clinical presentation of influenza. He also warned of the complications that can occur as a result of infection, especially in high-risk patients. Therefore, the goals for treatment are to attenuate signs and symptoms, prevent complications, decrease absenteeism, and prevent the spread of infection.

Dr Chahine discussed that patients with influenza who are indicated to receive antivirals are those who are hospitalized, outpatient with severe or progressive disease, or at high risk of complications. Special populations, such as patients younger than 2 years and those older than 65 years, pregnant women, or women postpartum of 2 weeks or less, are also considered high risk and should receive antiviral treatment. Dr Chahine then reviewed the mechanisms of action, activity, and indications of commonly used antivirals. He concluded his portion of the presentation with a case example to reinforce information learned.

At this point, Dr Sucher took over to further discuss antiviral treatment recommendations. Antivirals are to be used in indicated patients as soon as possible, ideally within 48 hours for maximum efficacy, and not to be held for laboratory confirmation of infection. The CDC and Infectious Diseases Society of America recommend treatment regardless of illness duration for hospitalized patients or outpatients with severe, complicated, or progressive illness. Dr Sucher discussed recommended dosing and efficacy data for antivirals indicated for treatment of adults and children with acute, uncomplicated influenza.

She then covered recent studies for influenza treatment, including the CAPSTONE-2 trial, which demonstrated the efficacy of baloxavir in high-risk patients. Baloxavir showed faster improvement of influenza symptoms and a reduction in the risk of complications when compared with placebo and similar efficacy to oseltamivir. The authors also found that baloxavir significantly reduced the time to improvement of symptoms for patients infected with influenza B as compared to oseltamivir. Furthermore, the miniSTONE-2 trial found similar efficacy to oseltamivir in terms of alleviation of signs and symptoms and incidence of adverse effects in healthy children between 1 and 12 years of age with acute, uncomplicated influenza.

Dr Sucher continued with a discussion of the recommendations for chemoprophylaxis and highlighted that annual vaccination remains the primary tool for influenza prevention. In the community, post-exposure chemoprophylaxis is not routinely recommended but can be considered for use in asymptomatic adults and children 3 months and older who are at very high risk of developing influenza complications as soon as possible (and within 48 hours) after household exposure to influenza. Dr Sucher discussed the use of oseltamivir and zanamivir for chemoprophylaxis. She presented data from the BLOCKSTONE trial, which led to the recent approval of baloxavir for chemoprophylaxis in adults and children aged 12 years and older.

Dr Sucher concluded by emphasizing the role of a pharmacist in the treatment and prevention of influenza through providing influenza immunization, identifying high-risk patients, recommending treatment, recognizing the role of prophylaxis, and counseling on antiviral agents. Antivirals continue to be underutilized in both hospitalized patients and outpatients with influenza, and pharmacists can help facilitate their early and appropriate use in these settings.