Partner Therapeutics Announces Publication of Clinical Trial Results of Leukine® (sargramostim) in Patients with Parkinson's Disease

LEXINGTON, Mass., May 19, 2021 /PRNewswire/ --Partner Therapeutics, Inc. (PTx), a commercial biotech company, announces the publication of results from an investigator-initiated clinical trial (NCT03790670) evaluating the use of Leukine® (sargramostim, yeast-derived rhuGM-CSF) in patients with Parkinson's Disease. Participants were evaluated for safety and tolerability as well as disease signs and symptoms including a standard Parkinson's mobility test (Movement Disorder Society (MDS) - Unified Parkinson's Disease Rating Scale Part III - UPDRS). Howard Gendelman, MD, chair of the University of Nebraska Medical Center (UNMC) Pharmacology and Experimental Neurology (PEN), together with Katherine Olson, PhD, Lee Mosley, PhD and Pamela Santamaria, MD and collaborators at UNMC published their findings in Lancet's open access journal, EBioMedicine ("Safety, tolerability, and immune-biomarker profiling for year-long sargramostim treatment of Parkinson's disease") (Olson, K., et al.) https://doi.org/10.1016/j.ebiom.2021.103380

Five patients were enrolled in the study and received 125 microgram/mm² of Leukine subcutaneously on a five-day-on, two-day-off regimen. All five patients completed the original 12 month treatment period. This was extended at patient and investigator request to 24 months and study size was expanded to 10 patients. Leukine was well-tolerated by patients during the twelve-month treatment period with no treatment-related serious adverse events and only mild to moderate adverse events reported. Reported adverse events in this study were significantly less frequent and of less severity than those reported in the previous placebo-controlled study at a higher Leukine dose (250 microgram/mm² every day). 

"The clinical paper studied Leukine, where disease progression was altered and the drug safely administered for one year," said Howard Gendelman, MD, chair of the UNMC Pharmacology and Experimental Neurology (PEN) and one of the lead researchers. "Additional research is required in a larger clinical study before definitive conclusions can be made for drug effectiveness."

"Treatments for Parkinson's disease, such as dopamine replacement therapy, treat the symptoms, not the disease," Dr. Santamaria said. "After a year of treatment in this study, none of our patients progressed."

Leukine treatment resulted in improvements in MDS-UPDRS Part III scores. Improved MDS-UPDRS Part III scores were observed in 4 of the 5 patients and there was no change in MDS-UPDRS Part III score over twelve months for the fifth patient. On average, MDS-UPDRS Part III scores improved by 4 points, compared to a 2.4 point average deterioration in MDS-UPDRS Part III score typically seen over twelve months in Parkinson's Disease patients receiving standard therapy. These improvements correlated with elevation in peripheral blood immunoregulatory phenotypes and function and indicate restoration of immune homeostasis and peripheral immune function. Leukine treatment improved immune function, enhanced T-regulatory cell numbers and function, and increased hypomethylation of upstream FOXP3. The researchers also discovered a spectrum of new blood tests that can monitor disease.  

"Congratulations to Dr. Gendelman and the team at UNMC for their ground-breaking pre-clinical and clinical work demonstrating Leukine's activity in restoring immune homeostasis and reducing neuro-inflammation by enhancing the protective effects of Tregs", said John McManus, Chief Business Officer at Partner Therapeutics. "Importantly, Leukine's effects on Tregs and neuro-inflammation translated into improvement in motor function in these patients. Our next step is to submit an IND for Parkinson's Disease and then initiate a Phase II, randomized, double-blind, placebo-controlled multi-site study to confirm these results in a larger population of patients.  Patients with Parkinson's have no treatment options that halt or reverse disease progression and we consider it a matter of urgency to accelerate Leukine's clinical development to provide a potential solution."

"The industry is in a pharmaceutical revolution in terms of the treatment of Parkinson's and Alzheimer's immunologically," Dr. Mosley said. "We've been exploring this treatment for more than a decade and this proof-of-concept study is an exciting step as we work to control the effects of Parkinson's Disease and improve people's lives."

In April 2021, researchers led by Huntington Potter, PhD at the University of Colorado reported that Leukine was safe and tolerable in patients with mild-to-moderate Alzheimer's disease (AD) (https://doi.org/10.1002/trc2.12158). Patients receiving Leukine experienced significant reversal of cognitive loss and biomarkers of disease progression. Leukine is the only FDA approved recombinant human GM-CSF and has a well understood safety profile based on use in more than 500,000 patients over the 30 years since its approval.   

See UNMC press announcement here.

ABOUT LEUKINE

LEUKINE® (sargramostim) is an FDA-approved, yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF). GM-CSF is a naturally occurring cytokine protein called a cytokine that plays an important role in myeloid hematopoiesis, immunomodulation, and cell reprogramming. Leukine is designated an Essential Medicine by FDA and is held by the U.S. Government in the Strategic National Stockpile. 

Leukine is indicated:

• To shorten time to neutrophil recovery and to reduce the incidence of severe and life-threatening infections and infections resulting in death following induction chemotherapy in adult patients 55 years and older with acute myeloid leukemia (AML).
• For the mobilization of hematopoietic progenitor cells into peripheral blood for collection by leukapheresis and autologous transplantation in adult patients.
• For the acceleration of myeloid reconstitution following autologous bone marrow or peripheral blood progenitor cell transplantation in adult and pediatric patients 2 years of age and older.
• For the acceleration of myeloid reconstitution following allogeneic bone marrow transplantation in adult and pediatric patients 2 years of age and older.
• For treatment of delayed neutrophil recovery or graft failure after autologous or allogeneic bone marrow transplantation in adult and pediatric patients 2 years of age and older.
• To increase survival in adult and pediatric patients from birth to 17 years of age acutely exposed to myelosuppressive doses of radiation (Hematopoietic Syndrome of Acute Radiation Syndrome [H-ARS]).

Important Safety Information for Leukine (sargramostim)

Contraindications

• LEUKINE is contraindicated in patients with known hypersensitivity to human granulocyte-macrophage colony stimulating factor such as sargramostim (GM-CSF), yeast-derived products, or any component of LEUKINE.

Warnings and Precautions

• Serious hypersensitivity reactions, including anaphylactic reactions, have been reported with LEUKINE. If any serious allergic or anaphylactic reaction occurs, immediately discontinue LEUKINE therapy and institute medical management. Permanently discontinue LEUKINE in patients with serious allergic reactions.
• LEUKINE can cause infusion-related reactions, including respiratory distress, hypoxia, flushing, hypotension, syncope and/or tachycardia. Observe closely during infusion, particularly in patients with preexisting lung disease, as dose adjustment or discontinuation may be required.
• Do not administer LEUKINE simultaneously with or within 24 hours preceding cytotoxic chemotherapy or radiotherapy or within 24 hours following chemotherapy.
• Edema, capillary leak syndrome, pleural and/or pericardial effusion have been reported in patients after LEUKINE administration. LEUKINE should be used with caution and monitored in patients with preexisting fluid retention, pulmonary infiltrates, or congestive heart failure.
• Supraventricular arrhythmia has been reported in uncontrolled studies during LEUKINE administration, particularly in patients with a previous history of cardiac arrhythmia. Use LEUKINE with caution in patients with preexisting cardiac disease.
• If ANC > 20,000 cells/mm³ or if WBC counts > 50,000/mm³, LEUKINE administration should be interrupted or the dose reduced by half. Twice weekly monitoring of CBC with differential should be performed.
• LEUKINE therapy should be discontinued if disease progression is detected during treatment.
• Treatment with LEUKINE may induce neutralizing anti-drug antibodies. Use LEUKINE for the shortest duration required.
• Liquid solutions containing benzyl alcohol (including LEUKINE Injection) or LEUKINE for Injection reconstituted with Bacteriostatic Water for Injection, USP (0.9% benzyl alcohol) should not be administered to neonates and low birth weight infants.
• Concomitant use of drugs that can potentiate the myeloproliferative effects of LEUKINE should be avoided.

Adverse Reactions

Adverse events occurring in >10% of patients receiving LEUKINE in controlled clinical trials and reported in a higher frequency than placebo are:

• In Autologous bone marrow transplantation (BMT) patients–asthenia, malaise, diarrhea, rash, peripheral edema, urinary tract disorder
• In Allogeneic BMT patients–abdominal pain, chills, chest pain, diarrhea, nausea, vomiting, hematemesis, dysphagia, GI hemorrhage, pruritus, bone pain, arthralgia, eye hemorrhage, hypertension, tachycardia, bilirubinemia, hyperglycemia, increased creatinine, hypomagnesemia, edema, pharyngitis, epistaxis, dyspnea, insomnia, anxiety, high glucose, low albumin
• In AML patients–fever, weight loss, nausea, vomiting, anorexia, skin reactions, metabolic laboratory abnormalities, edema

ABOUT PARTNER THERAPEUTICS

PTx, an integrated biotechnology company, focuses on development and commercialization of late-stage therapeutics to improve health outcomes in treatment of cancer and other serious diseases. The company believes in delivering products and supporting medical teams with the purpose of achieving superior outcomes for patients and their families. Visit www.partnertx.com.

SOURCE Partner Therapeutics, Inc.