Evaluating the Use of Oseltamivir for the Treatment of Influenza in Adults

• Time to alleviation of influenza clinical symptoms [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Time to absence of fever [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Time to resumption of normal activity [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Number of premature study treatment discontinuations [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Proportion of participants who develop bronchitis, pneumonia, or other complications of influenza [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Proportion of participants who require hospitalization [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• 28-day mortality [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Duration of viral shedding [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Change in viral shedding as a function of time [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Area under the curve (AUC) of viral shedding [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]
• Frequency of emergence of antiviral resistance [ Time Frame: Measured at Day 28 ] [ Designated as safety issue: No ]

People who are infected with the influenza virus may develop respiratory illnesses, such as pneumonia, or other life-threatening complications. Currently, there are four antiviral medications that are used to treat influenza. This study will examine one of these medications, oseltamivir, to examine how it affects the shedding of influenza virus in infected people.

Seasonal influenza is responsible for excess hospitalizations and, despite effective antivirals, causes significant morbidity and mortality (about 24,000 deaths each year in the United States alone). The influenza virus that emerged in 2009 (A/California/07/2009 H1N1) caused fewer deaths (12,000 flu-related deaths in the U.S.) but in contrast to seasonal flu, nearly 90% of the deaths with the 2009 H1N1 occurred among people younger than 65 years of age. Although there are four currently licensed anti-influenza medications (amantadine and rimantadine, oseltamivir, and zanamivir), previous studies have not demonstrated conclusively to what extent these medications affect influenza viral shedding. This study will evaluate whether oseltamivir modifies the viral shedding during the treatment of uncomplicated influenza in an adult population and also assess methods to detect viral replication in the upper respiratory tract.

Subjects who present with an influenza-like illness without any risk factors for severe disease will be screened for the study. Those with a confirmatory test for influenza (rapid antigen or polymerase chain reaction [PCR]) will be randomized in a 1:1 manner to receive a blinded study treatment consisting of either the oseltamivir or placebo for 5 days. Clinical, virologic, and laboratory assessments on Days 1, 3, 7, and 28 will be used for both safety and efficacy analysis.

• Drug: Oseltamivir
  One capsule twice daily of 75 mg oseltamivir; total dose: 150 mg/day for 5 days
• Drug: Oseltamivir Placebo
  One capsule twice daily of oseltamivir placebo; total dose: 2 placebo capsules/day for 5 days

• Experimental: Oseltamivir
  Participants will receive oseltamivir twice a day for 5 days.
  Intervention: Drug: Oseltamivir
• Placebo Comparator: Oseltamivir Placebo
  Participants will receive oseltamivir placebo twice a day for 5 days.
  Intervention: Drug: Oseltamivir Placebo

• Thompson WW, Shay DK, Weintraub E, Brammer L, Cox N, Anderson LJ, Fukuda K. Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA. 2003 Jan 8;289(2):179-86.
• Monto AS. Vaccines and antiviral drugs in pandemic preparedness. Emerg Infect Dis. 2006 Jan;12(1):55-60.

Inclusion Criteria:

• Written informed consent prior to initiation of any study procedures

• History of an influenza-like illness defined as:

  1. One or more respiratory symptom (cough, sore throat, or nasal symptoms) and either:
  2. Fever (subjective or documented ≥ 38.0°C) or
  3. One or more constitutional symptom (headache, malaise, myalgia, sweats/chills, or fatigue)
• Onset of illness no more than 48 hours before screening, defined as when the participant experienced at least one respiratory symptom and constitutional symptom or fever
• Willing to have samples stored
• Positive test for influenza (either rapid antigen or polymerase chain reaction [PCR]); randomization may proceed in cases of discrepant results (one positive and one negative)

Exclusion Criteria:

• Hospitalization at the time of screening

• Presence of a medical condition(s) that has been associated with increased risk of complications from influenza

  1. Age 65 years of age or older
  2. Asthma
  3. Neurological and neuro-developmental conditions (including disorders of the brain, spinal cord, peripheral nerve, and muscle, such as cerebral palsy, epilepsy [seizure disorders], stroke, moderate to severe developmental delay, muscular dystrophy, or spinal cord injury)
  4. Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] or cystic fibrosis)
  5. Heart disease (such as congenital heart disease, congestive heart failure, or coronary artery disease)
  6. Blood disorders
  7. Endocrine disorders (such as diabetes mellitus)
  8. Kidney disorders
  9. Liver disorders
  10. Metabolic disorders (such as inherited metabolic disorders or mitochondrial disorders)
  11. Weakened immune system due to disease or medication (such as people with HIV/AIDS or cancer, or use of chronic steroids or other medications causing immune suppression)
  12. Pregnant or 4 weeks postpartum
  13. Body mass index (BMI) greater than or equal to 40
• Breastfeeding
• Inability to take oral medication or a history of gastrointestinal malabsorption that would preclude the use of oral medication
• Received more than one dose of any antiviral influenza medication since onset of influenza symptoms
• Known end stage kidney dysfunction (e.g., creatinine clearance less than 30 mL/min)
• Known hypersensitivity to oseltamivir, peramivir, or zanamivir
• Received live attenuated influenza virus vaccine within 3 weeks prior to study entry
• Use of any investigational drug within 30 days or 5 half-lives (whichever is longer) prior to study entry