Inclusion Criteria Subjects must meet all of the following criteria to be considered eligible to participate in the study: 1. Subjects >= 6 years of age at time of Informed Consent Form (ICF) or Assent Form signing. 2. Confirmed diagnosis of CF, determined by having clinical features consistent with the CF phenotype, plus 1 of the following: a. Positive sweat chloride test (value >= 60 mEq/L), b. Genotype with 2 mutations consistent with CF (ie, a mutation in each of the cystic fibrosis transmembrane conductance regulator [CFTR] genes). 3. Positive sputum culture or a throat swab culture for MRSA at Screening. 4. In addition to the Screening sample, have at least 2 prior sputum or throat swab cultures positive for MRSA, of which at least 1 sample is more than 6 months prior to Screening. At least 50% of all MRSA cultures (sputum or throat swab culture) collected from the time of the first positive culture (in the previous 1 year) must have tested positive for MRSA.(Note: screening sample may count towards 50% positive count.) 5. Forced expiratory volume in 1 second (FEV1) >= 30% and <= 90% of predicted that is normal for age, gender, race, and height, using the Global Lung Function Initiative (GLI) equation. 6. At least 1 episode of acute pulmonary infection treated with non-maintenance antibiotics within 12 months prior to the Baseline visit. (Initiation of treatment with intermittent inhaled anti-Pseudomonal therapy will not qualify as treatment with non-maintenance antibiotics). 7. If female of childbearing potential, an acceptable method of contraception must be used during the course of the study and must be combined with a negative pregnancy test obtained during Screening; sexually active male subjects of reproductive potential who are non-sterile (ie, male who has not been sterilized by vasectomy for at least 6 months and were not diagnosed with infertility through demonstration of azoospermia in a semen sample and/or absence of vas deferens through ultrasound) must be willing to use a barrier method of contraception, or their female partner must use an acceptable method of contraception, during the course of the study. For purposes of this study, the Sponsor defines * acceptable methods of contraception * as: as: a. Oral birth control pills administered for at least 1 monthly cycle prior to administration of the study drug b. A synthetic progestin implanted rod (eg, Implanon(RegisteredTM)) for at least 1 monthly cycle prior to the study drug administration but not beyond the 4th successive year following insertion c. Intrauterine devices (IUDs), inserted by a qualified clinician for at least 1 monthly cycle prior to study drug administration d. Medroxyprogesterone acetate (eg, Depo-Provera(RegisteredTM)) administered for a minimum of 1 monthly cycle prior to administration of the study drug and continuing through 1 month following study completion. e. Hysterectomy or surgical sterilization f. Abstinence g. Double barrier method (diaphragm with spermicidal gel or condoms with contraceptive foam) NOTE: For subjects prescribed Orkambi: Orkambi may substantially decrease hormonal contraceptive exposure, reducing the effectiveness and increasing the incidence of menstruation-associated adverse reactions. Hormonal contraceptives, including oral, injectable, transdermal, and implantable, should not be relied upon as an effective method of contraception when co-administered with Orkambi. 8. Able and willing to comply with the protocol, including availability for all scheduled study visits and be able to perform all techniques necessary to use the AeroVanc inhaler and measure lung function. 9. Agree not to smoke during any part of the clinical trial (Screening visit through end of study). 10. Subjects with a P. aeruginosa co-infection must either be stable on a regular suppression regimen of inhaled antibiotics or must be, in the opinion of the Investigator, stable despite the lack of such treatment.