Partner Therapeutics’ Leukine® (Sargramostim) Gets Approval in Japan
Partner Therapeutics’ Leukine® (sargramostim) Granted Approval in Japan for Treating Autoimmune Pulmonary Alveolar Proteinosis (aPAP)
Overview
Partner Therapeutics, Inc. (PTx) has recently announced that Nobelpharma, its partner, has received approval from the Japanese Pharmaceuticals and Medical Device Agency (PMDA) for the inhaled use of Leukine (sargramostim), which is branded as Sargmalin in Japan, for the treatment of aPAP (autoimmune pulmonary alveolar proteinosis). In 2022, PTx licensed certain indications rights for Japan to Nobelpharma. Leukine, a recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) produced via recombinant DNA technology in yeast, has not yet been approved for aPAP treatment via inhalation outside Japan. PTx will be manufacturing Sargmalin for Nobelpharma at its facility in Lynnwood, WA.
PAGE Trial Behind Approval
The approval of Sargmalin is supported by data from the PAGE trial, a phase 2 multicenter study led by Sponsor-Investigator Koh Nakata MD, PhD, Project Professor at Niigata University Medical Dental Hospital.
This trial, which was randomized, double-blind, and placebo-controlled, involved 64 patients with mild to moderate aPAP.
Patients were randomly assigned to receive either 125 micrograms of Leukine or a placebo twice daily for seven days, followed by a seven-day break, for twelve two-week cycles.
The primary endpoint, improvement in alveolar–arterial oxygen gradient (A-aDO2) between baseline and week 25, showed significant enhancement (p=0.02).
Additionally, Leukine demonstrated greater improvements in secondary endpoints such as serum biomarkers KL-6, CEA, and monocyte chemoattractant protein-1 (MCP-1).
Words from Partner Therapeutics
Robert Mulroy, CEO of Partner Therapeutics, expressed gratitude towards Nobelpharma for their partnership and commitment to making Sargmalin available to aPAP patients in Japan. Mulroy also acknowledged the contribution of patients and doctors participating in the investigator-initiated clinical trial conducted by Dr. Nakata of Niigata University.
aPAP Mechanism and Consequences
The investigation into inhaled sargramostim for aPAP is based on the understanding that this disease is a progressive lung disorder primarily caused by GM-CSF signaling blockage due to the presence of GM-CSF autoantibodies.
This deficiency inhibits the differentiation of monocytes into alveolar macrophages, leading to surfactant accumulation in the lungs.
Consequently, patients suffer from low oxygen levels, breathing difficulties, and immune deficiency, with potential complications including serious infections, pulmonary fibrosis, respiratory failure, and death.
GM-CSF addresses these issues by promoting alveolar macrophage maturation and surfactant breakdown.
Whole Lung Lavage
Traditionally, Whole Lung Lavage (WLL) has been the standard treatment for aPAP.
However, it is a lengthy and invasive procedure requiring hospitalization, general anesthesia, and mechanical ventilation.
Despite providing short-term relief, WLL does not address the underlying alveolar macrophage dysfunction.
LEUKINE
LEUKINE (sargramostim) is a glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) produced by recombinant DNA technology in yeast.
It is commercially available in the United States and accessible internationally through a named patient program operated by Tanner Pharma Group.