A Study of the Dosing, Efficacy, and Safety of Oral Cysteamine in Adult Patients With Cystic Fibrosis Exacerbations

Inclusion Criteria: 1. CF-associated lung disease with documented history of chronic infection with Gram-negative organism(s) 2. Established patient of the Principal Investigator's CF Multi Disciplinary Team (MDT) 3. Age ≥18 years 4. Weight \>40 kg 5. FEV1 \>30% of predicted within the 6 months prior to study exacerbation 6. At the baseline visit: experiencing a new exacerbation of CF-associated lung disease (based on Investigator assessment of ≥4 symptoms present on the Fuchs' criteria) requiring treatment that includes an aminoglycoside antibiotic 7. Females of childbearing potential will be included if they are either sexually inactive (sexually abstinent for 14 days prior to the first study drug dose continuing through 28 days after the last study drug dose, or using one of the following highly effective contraceptive (i.e. results in \<1% failure rate when used consistently and correctly) methods in this trial: 1. intrauterine device (IUD); 2. surgical sterilization of the partner (vasectomy for 6 months minimum); 3. combined (estrogen or progestogen containing) hormonal contraception associated with the inhibition of ovulation (either oral, intravaginal, or transdermal); 4. progestogen only hormonal contraception associated with the inhibition of ovulation (either oral, injectable, or implantable); 5. intrauterine hormone releasing system (IUS); 6. bilateral tubal occlusion. 8. Females of childbearing potential agree to remain sexually inactive or to keep the same birth control method for at least 28 days following the last dose. 9. A female of non-childbearing potential must have undergone one of the following sterilization procedures at least 6 months prior to the first study drug dose: 1. hysteroscopic sterilization; 2. bilateral tubal ligation or bilateral salpingectomy; 3. hysterectomy; 4. bilateral oophorectomy; or be postmenopausal with amenorrhea for at least 1 year prior to the first study drug dose and follicle stimulating hormone (FSH) serum levels consistent with postmenopausal status. 10. A non-vasectomized male subject agrees to use a condom with spermicide or abstain from sexual intercourse during the study until 90 days beyond the last dose of study medication and the female partner agrees to comply with inclusion 7 or 9. For a vasectomized male who has had his vasectomy 6 months or more prior to study start, it is required that they use a condom during sexual intercourse. A male who has been vasectomized less than 6 months prior to study start must follow the same restrictions as a non-vasectomized male. 11. If male, agrees not to donate sperm from the first study drug dose until 90 days after dosing. 12. Willing and able to comply with all protocol requirements and procedures, including induction of sputum, if necessary 13. Willing and able to provide signed and dated informed consent Exclusion Criteria: 1. Hypersensitive to cysteamine or to any of the excipients 2. Hypersensitive to penicillamine 3. Transplant recipient 4. Participation in any other interventional clinical research study (participation in observational studies is not exclusionary) within 30 days of Baseline (Day 0), and any planned participation in an interventional clinical research study for the duration of this study 5. If female, pregnancy, planned pregnancy, or breast-feeding 6. Any other significant disease/disorder which, in the Investigator's opinion, either puts the patient at risk due to study participation, or may influence the results of the study or the patient's ability to participate in the study