1184. Clinical Experience with Intravenous Zanamivir for Influenza Treatment under an Emergency IND program in the United States
Session: Poster Abstract Session: New Approaches to Anti-Viral Therapy
Saturday, October 22, 2011
Room: Poster Hall B1
Background: No intravenous (IV) influenza antivirals are approved in the U.S. Since the emergence of 2009 H1N1 virus, IV zanamivir has been permitted as an investigational treatment for patients with serious and life-threatening influenza through an Emergency Investigational New Drug application (EIND).

Methods: Retrospective descriptive review of patient clinical data in FDA’s IV zanamivir EIND database from April 2009-April 2011.

Results: Of 200 IV zanamivir EIND requests, most patients (75%) were aged 18-64 years; 14 (7%) were pregnant, 20% were children. 103 patients (52%) had ≥1 co-morbidity reported, including cancer (n=36), chronic lung disease (n=26), diabetes (n=9), obesity (n=17), chronic renal failure (n=8), heart disease (n=7), or HIV/AIDS (n=2). The majority (76%) were receiving oseltamivir when IV zanamivir was requested, and 26% had either confirmed (n=18; 11/18 were immunosuppressed) or suspected (n=34; no improvement or worsening on oseltamivir) H275Y oseltamivir resistance. Influenza A was reported for 177 patients: confirmed 2009 H1N1 (n=98), suspected 2009 H1N1 (n=18), confirmed H3N2 (n=1), not subtyped (n=60). Influenza B was reported for 12 patients. Median time from hospital admission to IV zanamivir request was 12 days (range, 1-32 days; n=51). Many patients (67%) required invasive mechanical ventilation, 16 received high frequency oscillatory ventilation, and 27 received ECMO. 81% had ≥1 complication such as renal failure (n=50; 38/50 required dialysis), bacterial infection (n=19), shock (n=25), or pneumonia (n=73). Data on IV zanamivir treatment duration were available for 40 patients (20%), of whom 22 received <5 days of treatment and 18 received >5 days of treatment. Of 47 patients (24%) with available outcome data, 21 died, and 26 survived.  

Conclusion: Use of IV zanamivir under EIND was for treatment of critically ill adult patients with 2009 H1N1, including a substantial number with confirmed or suspected oseltamivir resistance. Data from prospective, randomized controlled trials are needed to assess the safety and efficacy of IV zanamivir for treatment of hospitalized patients with severe influenza.

Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

Kirk Chan-Tack1, Arlene Gao2, Amalia Himaya2, Elizabeth Thompson2, Mary Singer2, Timothy Uyeki, MD3 and Debra Birnkrant2, (1)FDA, Silver Spring,, MD, (2)FDA, SILVER SPRING, MD, (3)Influenza Division, CDC, , Atlanta, GA


K. Chan-Tack, None

A. Gao, None

A. Himaya, None

E. Thompson, None

M. Singer, None

T. Uyeki, None

D. Birnkrant, None

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