Partner Therapeutics Announces Publication of Clinical Trial Results Showing Significant Benefit with Use of Leukine® (sargramostim) in Patients with Alzheimer's Disease

LEXINGTON, Mass., March 24, 2021 /PRNewswire/ -- Partner Therapeutics, Inc. (PTx), a commercial biotech company, announces the publication of results from an investigator-initiated clinical trial (NCT01409915) evaluating the use of Leukine® (sargramostim, yeast-derived rhuGM-CSF) in patients with mild-to-moderate AD. Participants were evaluated for safety and tolerability, as well as cognitive function and markers of AD pathology. Professor Huntington Potter, together with Jonathan Woodcock, Timothy Boyd and collaborators at the University of Colorado (CU) Alzheimer's and Cognition Center published their findings in Alzheimer's & Dementia: Translational Research and Clinical Interventions, an open access journal of the Alzheimer's Association ("The Safety and Efficacy of GM-CSF (Sargramostim) in the Treatment of Alzheimer's Disease" (Potter, Woodcock, Boyd, et al.); DOI: 10.1002/trc2.12158.

According to Dr. Potter, "The goal of the clinical trial was to examine the impact of a natural human protein called granulocyte-macrophage colony stimulating factor (GM-CSF) on people living with Alzheimer's disease. We tested Leukine because people with rheumatoid arthritis tend not to get Alzheimer's disease and we had previously found GM-CSF, which is increased in the blood of people with rheumatoid arthritis, reduced amyloid deposition in Alzheimer's mice and returned their poor memory to normal after a few weeks of treatment. Thus, naturally increased levels of GM-CSF in people with rheumatoid arthritis may be one reason that they are protected from Alzheimer's disease. Human GM-CSF is the active compound in the known human drug Leukine, and we are the first to study its effect on people with Alzheimer's disease."

The researchers carried out a randomized, double-blind, placebo-controlled phase II trial to test safety and efficacy of Leukine treatment in participants with mild-moderate Alzheimer's disease. Participants who met eligibility criteria were randomized to receive injections of either Leukine (20 patients received Leukine at a dose of 250 mcg/m²/day subcutaneous injection for five days a week for three weeks) or placebo (20 patients took saline for five days a week for three weeks). Most study participants from the study were recruited and treated at CU Anschutz with three from the University of South Florida.

The CU Anschutz researchers conducted and studied multiple neurological, neuropsychological, cell, cytokine, Alzheimer's pathology biomarkers, and neuroimaging assessments. They found that short term treatment with Leukine:

1. was safe and well-tolerated by participants and the most common Leukine-associated adverse events were dermatological (16 for Leukine vs. 5 for placebo), gastrointestinal (8 for Leukine vs. 5 for placebo), and headache (8 for Leukine vs. 2 for placebo), as expected for this medication; side effects were consistent with the Leukine label and there were no serious adverse events related to study drug;
2. showed significant reversal of cognitive loss, as measured by the MMSE (Mini-Mental State Exam, an AD assessment): cognitive measures of memory improved by almost 2 points in the 30 point MMSE compared to baseline (P=0.0074); Leukine-treated patients did better than placebo-treated patients (P=0.0370) after three weeks of treatment; this improvement lasted up to 45 days post treatment (P=0.0272);
3.  modulated blood based biomarkers of AD towards normal levels; plasma amyloid marker Abeta40 (decreased in AD) increased 10% (p=0.0105), and plasma markers of neurodegeneration (total Tau and UCH-L1) decreased 24% (p=0.0174) and 42% (p=0.0019), respectively, after treatment with Leukine compared to placebo; and
4.  increased innate and other immune cells and modulated cytokine measures.

"These results suggest that short-term Leukine treatment leads to innate immune system activation, cognition and memory improvement, and partial normalization of blood measures of amyloid and tau pathology and neuronal damage in participants with mild-to-moderate Alzheimer's disease," said Dr. Potter. He added, "this surprising finding that stimulating the innate immune system may be a new treatment approach induced us to start a larger trial of Leukine in Alzheimer's disease with more participants treated over a longer time. This new trial will be funded by the Alzheimer's Association/Part The Cloud, the University of Colorado, the Global Down Syndrome Foundation and by a large grant recently awarded from the National Institute on Aging".

"Leukine has unique immunomodulatory properties and we commend Professor Potter and his team for taking their observations in rheumatoid arthritis and "chemo-brain" and applying them to Alzheimer's disease," said Debasish Roychowdhury, PTx's Chief Technology Officer. "The study was rigorously conducted with numerous measures aimed at studying the effect on the clinical and pathological parameters while also discerning the basic mechanism. We are excited to see that Leukine, even in the short term, can potentially be disease modifying. This study adds to a growing body of research indicating the potential benefits of Leukine's effects on tissue resident macrophages, such as microglial cells in AD or alveolar macrophages in aPAP or severe COVID-19."

Leukine is not approved for the treatment of Alzheimer's disease.

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 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 available outside of the United States through a Named Patient Program administered by Tanner Pharma Group.

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.

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