Safety and Protective Efficacy of FF-3 Dry Powder in Healthy Subjects Infected With Influenza Challenge Strain

Inclusion Criteria: 1. Healthy male and non-pregnant, non-lactating female subjects of 18 to 50 years of age inclusive 2. Body Mass Index (BMI) of 18 to 32 kg/m2 inclusive and body weight of 50 to 110 kg inclusive. 3. Normal spirometry values at Screening and Baseline 4. Post-menopausal women with amenorrhea for at least 2 years will be eligible 5. Females of childbearing potential must use two acceptable birth control methods throughout the study and for 30 days after the last dose of the IMP: 6. Male subjects: * Must agree to use a condom (or diaphragm) plus spermicide in female partner) from the time of the first dose of IMP through 90 days after the last dose. * Must agree to not donate sperm for 90 days after the last dose of IMP. * Documented evidence of vasectomies in males for 180 days minimum prior to the first dose of the IMP is an acceptable form of contraception. * Males who claim abstinence as their method of contraception are allowed provided they agree to use a double barrier method (diaphragm plus spermicide in female partner or condom) should they become sexually active from screening to 90 days after the last dose of IMP. 7. Willing and able to provide written informed consent. 8. Willing and able to adhere to the lifestyle guideline restrictions outlined in the protocol Exclusion Criteria: * Subjects may not be enrolled in the study if any of the following exclusion criteria are fulfilled: 1. Evidence of or history of clinically significant oncologic, pulmonary, hepatic, gastrointestinal, cardiovascular, hematologic, metabolic, neurological, immunologic, nephrologic, endocrine , or psychiatric disease. 2. Current infection of any nature unless agreed as insignificant to the study by the Investigator and Medical Monitor. 3. Nasal abnormalities, including nasal septum deviation, septum perforations, or polyps; history of recurrent epistaxis; history of sinus surgery and/or persistent hypertrophic inferior turbinates. 4. Significant abnormalities at screening in safety laboratory tests, ECGs, or spirometry. 5. Broncho-reactive airway disease (asthma, chronic obstructive pulmonary disease, current allergic rhinitis, cystic fibrosis, chronic bronchitis, emphysema). Individuals with a history of childhood asthma are not necessarily excluded and acceptable for screening. 6. History of significant nasal irritation from use of nasal sprays or drops. 7. History of drug or alcohol abuse within the past 2 years 8. Nicotine product users 9. Received an investigational drug or participated in another research study within 90 days of the first dose of IMP. 10. Participated in a previous investigational study of FF-3. 11. History of influenza vaccination with a live or attenuated vaccine within the previous year 12. Use of prescription drugs within 14 days prior to the first dose of IMP, excepting oral contraceptives. 13. Received any non-prescription medications, vitamins, or dietary supplements within 14 days of administration of the first dose of IMP, unless both the Principal Investigator and the Medical Monitor grant prior approval. Herbal supplements must be discontinued 7 days prior to the first dose of IMP. 15\. Tested positive for alcohol at screening or admission to the CRU. 16. Positive urine pregnancy test at the Screening Visit or positive serum pregnancy test on admission to the CRU (females only). 17\. Positive test for HIV, hepatitis B surface antigen (HBsAg) or anti-hepatitis C virus (anti-HCV) at the screening visit. 18\. Positive urine drug test at the screening visit or at admission to the CRU. 19. Likelihood of requiring treatment during the study period with drugs not permitted by the study protocol. 20\. Subjects who have donated blood or experienced other significant blood loss within 56 days of screening for the study.