A Randomized, Double-blind, Single Center, Phase 2 Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of 15 mg of Darifenacin Daily in Patients With Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disorder characterized by selective death of upper and lower motor neurons, which leads to severe disability and fatal outcomes. One of the major hallmarks of ALS is the denervation of neuromuscular junctions (NMJs), which is one of the earliest events seen in ALS patients and mouse models of ALS. Under healthy conditions, glial cells called Perisynaptic Schwann Cells (PSCs) have a key role in regulating the stability and maintenance of NMJs, but they only participate in NMJ repair once denervation occurs. Denervation and the subsequent decline in synaptic activity triggers a loss of muscarinic acetylcholine receptors (mAChRs) in the PSC, and the resulting decrease in mAChR-mediated gene expression drives the repair mode of the PSC. In assessing the NMJ under conditions of ALS, a scarcity of process extensions in PSCs was observed for months prior to disease onset in the superoxide dismutase 1 (SOD1) mouse model of ALS, indicating inadequate glial repair. Collectively, these preclinical findings support the hypothesis that dampening glial mAChRs will restore the anticipated repair response of PSCs in the NMJ. Hence, the use of a selective M3 muscarinic receptor antagonist, Darifenacin, as a disease-modifying therapeutic in familial and sporadic ALS could improve NMJ function, resulting in a beneficial impact on the autonomy and quality of life of ALS patients. The purpose of the current Phase 2 trial is therefore to test the safety, tolerability, and pharmacology of Darifenacin in patients with ALS. Specifically, 30 eligible subjects between 18 and 85 years of age will take 7.5 mg of darifenacin or placebo daily (by mouth) for two weeks followed by an increased dose of 15 mg for the next 22 weeks. The trial will evaluate the effects of this medication on several outcome measures including patient safety, physical and neurological function, muscle strength, depression levels, and NMJ innervation of patients with ALS. Detailed clinical assessments will be conducted at regular intervals throughout the study in order to achieve these objectives.
• Able to comprehend and willing to sign an Informed Consent Form (ICF).
• Male or female, ≥ 18 years old and ≤85 years old, at the time of signing the ICF.
• Confirmed diagnosis of familial or sporadic ALS, defined as meeting the probable, laboratory-supported probable, or definite criteria for a diagnosis of ALS according to the World Federation of Neurology Modified El Escorial criteria (1).
• ALS duration of less than 36 months from the symptom onset.
• FVC of ≥ 50 %.
• Able to swallow tablets without crushing.
• A female patient is eligible to participate if she is not breastfeeding, has negative pregnancy test at screening, has no intention of becoming pregnant during the course of the study, and agrees to use appropriate contraceptive drugs or devices (as defined in section 3.4 of the study protocol) for the duration of the study.
• If male and has a partner who may become pregnant, agrees to ensure that he and/or his partner use a reliable form of birth control (as defined in section 3.4 of the study protocol) for the duration of the study and refrain from donating sperm during this period.
• Participants receiving standard care for ALS prior to entering the trial (i.e. Riluzole, Edaravone, and Albrioza), must be on a stable dosing regimen prior to the randomization and agree to remain on this dosage during the study period:
‣ In the case of taking Riluzole, the patient must have been on a stable dose at least 30 days prior to start date.
⁃ In the case of taking Edaravone, the patient must have been on a stable dose at least 30 days prior to start date.
⁃ In the case of receiving Albrioza, the patient must have been on a stable dose at least 30 days prior to start date.
⁃ For participants who consent to the optional biopsy:
∙ Participants with normal platelet or coagulation test values.
‣ Participants who are receiving anticoagulant medications will need to abstain from using anticoagulants for a specific number of days before and after the biopsy, as decided by the study doctor on a case-by-case basis.