Efficacy and Safety of Inhaled Molgramostim (rhGM-CSF) in Autoimmune Pulmonary Alveolar Proteinosis

This study evaluates inhaled molgramostim (recombinant human granulocyte macrophage-colony stimulating factor \[rhGM-CSF\]) in the treatment of autoimmune pulmonary alveolar proteinosis (aPAP) patients. A third of the patients will receive inhaled molgramostim once daily for 24 weeks, a third will receive inhaled molgramostim intermittently (7 days on, 7 days off) for 24 weeks and a third will receive inhaled matching placebo for 24 weeks.

The trial is a phase 2, randomized, double-blind, placebo-controlled multicentre clinical trial investigating efficacy and safety of inhaled molgramostim (rhGM-CSF) in patients with aPAP.

The trial will include 2 periods; a double-blind treatment period consisting of up to 8 trial visits (Screening, Baseline, and at Weeks 4, 8,12, 16, 20 and 24 after randomisation) and a open-label follow-up period consisting of up to 5 trial visits (at Weeks 4, 12, 24, 36 and 48 post-treatment).

In the double-blind treatment period, eligible subjects will be randomised to treatment for up to 24 weeks with either: 1) inhaled molgramostim (300 µg) once daily (MOL-OD), 2) inhaled molgramostim (300 µg) and matching placebo administered intermittently (7 days on and 7 days off) (MOL-INT) or 3) inhaled placebo once daily (PBO). During the follow-up period, all participants will receive inhaled molgramostim intermittently (7 days on, 7 days off). During the trial, whole lung lavage (WLL) may be applied as rescue therapy in case of significant clinical worsening.

Eligibility Criteria:
Inclusion Criteria:

* aPAP diagnosed by computed tomography, or by biopsy, or by Broncho Alveolar Lavage (BAL), and by increased GM-CSF autoantibodies in serum.
* Stable or progressive aPAP during a minimum period of 2 months prior to the Baseline visit.
* Arterial oxygen tension (PaO2) \<75 mmHg/\<10 kilo Pascal (kPa) at rest, OR desaturation of \>4 percentage points on the 6MWT
* An alveolar-arterial oxygen difference \[(A-a)DO2\] of minimum 25 mmHg/3.33 kPa
* Female or male ≥18 years of age
* Females who have been post-menopausal for \>1 year or females of childbearing potential after a confirmed menstrual period using a highly efficient method of contraception (i.e. a method with \<1% failure rate such as combined hormonal contraception, progesterone-only hormonal contraception, intrauterine device, intrauterine hormone-releasing system, bilateral tubal occlusion, vasectomised partner, sexual abstinence), during and until 30 days after last dose of double-blind trial treatment. Females of childbearing potential must have a negative serum pregnancy test at Screening (Visit 1) and a negative urine pregnancy test at dosing at Baseline (Visit 2) and must not be lactating
* Males agreeing to use condoms during and until 30 days after last dose of double-blind medication, or males having a female partner who is using adequate contraception as described above
* Willing and able to provide signed informed consent
* Willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other trial procedures specified in the protocol as judged by the investigator

Exclusion Criteria:

* Diagnosis of hereditary or secondary PAP
* WLL within 1 month of Baseline
* Treatment with GM-CSF within 3 months of Baseline
* Treatment with rituximab within 6 months of Baseline
* Treatment with plasmapheresis within 3 months of Baseline
* Treatment with any investigational medicinal product within 4 weeks of Screening
* Concomitant use of sputum modifying drugs such as carbocysteine or ambroxol
* History of allergic reactions to GM-CSF
* Connective tissue disease, inflammatory bowel disease or other autoimmune disorder requiring treatment associated with significant immunosuppression, e.g. more than 10 mg/day systemic prednisolone
* Previous experience of severe and unexplained side-effects during aerosol delivery of any kind of medicinal product
* History of, or present, myeloproliferative disease or leukaemia
* Known active infection (viral, bacterial, fungal or mycobacterial)
* Apparent pre-existing concurrent pulmonary fibrosis
* Any other serious medical condition which in the opinion of the investigator would make the participant unsuitable for the trial