Cough Reduction in IPF with Nalbuphine ER

This is a multi-center randomized, double-blind, placebo-controlled, parallel, 4-arm study of nalbuphine ER (NAL ER).

After meeting eligibility during the Screening Period, subjects will be randomized (1:1:1:1) to one of four treatment arms with placebo and increasing doses of nalbuphine ER. Each arm will be titrated to their fixed dose during the blinded 2-week Titration period followed by the 4-week Fixed Dose Period for a total of 6 weeks on drug.

For more information see the country specific approved websites:

Germany, Netherlands, Poland, Spain, Italy, Chile: TheCoralTrial.com United Kingdom, Australia, Canada: CoralCoughTrial.com Turkey: please refer to the list of locations and reach out to the site directly

This is a multi-center randomized, double-blind, placebo-controlled, parallel, 4-arm study.

After meeting eligibility during the Screening Period, subjects will be randomized (1:1:1:1) to one of four treatment arms.

* Arm 1: Placebo
* Arm 2: 27 mg nalbuphine ER
* Arm 3: 54 mg nalbuphine ER
* Arm 4: 108 mg nalbuphine ER

Each arm will be titrated to their fixed dose during the blinded 2-week Titration period according to Table: Dosing Scheme, followed by the 4-week Fixed Dose Period for a total of 6 weeks on drug.

Subjects will be taken off study drug at the end of the Fixed Dose Period and followed off treatment for an additional 2 weeks.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of IPF as determined by the Principal Investigator based on ATS/ERS/JRS/ALAT guidelines.
* Cough Severity Score ≥ 4 on CS-NRS (Cough Severity Numerical Rating Scale) during the Screening period and Baseline.
* History of chronic cough for at least 8 weeks before screening.
* SpO2 ≥ 92%, taken after at least 5 minutes in a sitting position, undisturbed and non-stimulated (Saturation of Hemoglobin with Oxygen as Measured by Pulse Oximetry).
* FVC ≥ 40% predicted of normal - Forced Vital Capacity, as determined by spirometry adhering to ATS/ERS guidelines.
* DLCO ≥ 25% predicted of normal - Diffusing capacity of the lung for carbon monoxide corrected for hemoglobin, assessed within the last 12 weeks, or at the time of screening.

Exclusion Criteria:

* Currently on continuous oxygen therapy for longer than 16 hours at any level or delivered by any modality. Intermittent oxygen use of any duration over any given 24-hour period is allowed.
* Inadequate swallow reflex as assessed by the ability to sip 3 fluid oz (or 89 mL) of water without coughing or choking.
* Upper or lower respiratory tract infection in the last 8 weeks prior to the baseline visit.
* Clinical history of aspiration pneumonitis.
* Diagnosis of sleep apnea.
* Abnormal kidney or liver functions based on Screening lab results.
* Known hypersensitivity to nalbuphine or to NAL ER excipients
* History of major psychiatric disorder.
* History of substance abuse.
* Significant medical condition or other factors that may interfere with the subject's ability to successfully complete the study.
* Pregnant or lactating female subject.
* Known intolerance (gastrointestinal, central nervous system symptoms), hypersensitivity, drug allergy following the use of an opioid drug.
* Use of opiates is prohibited within 14 days prior to the baseline visit.
* Use of benzodiazepines are prohibited within 14 days prior to the baseline visit and for the duration of the study.
* Monoamine oxidase inhibitors (MAOIs) including methylene blue (methylthioninium chloride) and the antibiotic linezolid are prohibited within 14 days prior to the baseline visit and for the duration of the study.
* Use of oral corticosteroid cough treatment is prohibited within 4 weeks prior to the baseline visit and for the duration of the study.
* Exposure to any investigational medication, including placebo, is prohibited within 4 weeks prior to the baseline visit and for the duration of the study.
* Medications prescribed as cough suppressants are prohibited unless on a stable dose 14-days prior to the baseline visit and are expected to remain on that dose for the duration of the study.
* Use of medications that affect serotonergic neurotransmission and that when used concomitantly with opioids can increase the risk of serotonin syndrome are prohibited unless on a stable dose 14-days prior to the baseline visit and are expected to remain on that dose for the duration of the study.
* Anti-fibrotic medications are prohibited unless on a stable dose for 8 weeks prior to the baseline visit and are expected to remain on that dose for the duration of the study.
* Strong inhibitors/inducers of the P450 Isozymes are prohibited unless on a stable dose for 14-days prior to baseline visit and are expected to remain on that dose for the duration of the study.
* Use of a medication having a "known risk" of Torsade de Pointes (categorized as "KR" on the Credible Meds® website.) 4 weeks prior to Baseline.
* Use of unstable doses of medications associated with a potential risk of QT prolongation but not clearly associated with Torsade de Pointes within 4 weeks of screening.