INDICATIONS UNDER DEVELOPMENT
Alzheimer’s disease is a chronic neurodegenerative disease characterized by progressive neuronal death in the brain. This neuronal loss leads to thinking, memory, personality and behavior disorders and ultimately to death, with an average survival time of ten years after disease onset. Alzheimer’s disease affects around 44 million people worldwide. Current therapies such as cholinesterase inhibitors (Aricept®) and N-methyl D-Aspartate antagonists (Namenda®/Ebixa®) are only moderately effective in symptomatic relief while not modifying disease progression and being associated with adverse events.
Parkinson’s disease is a chronic neurodegenerative disease characterized by progressive loss of dopaminergic neurons in the brain, causing motor disorders including bradykinesia, rigidity, tremors and postural instability. It affects around 6 million people in the world. Current treatments (L-Dopa, monoamine oxydase inhibitors and dopaminergic agonists) aim at replacing dopamine deficiency. They are only symptomatic, do not address neuronal loss and are often associated with adverse effects (such as abnormal involuntary movements).
AMYOTROPHIC LATERAL SCLEROSIS (ALS)
ALS is an orphan chronic neurodegenerative disease characterized by progressive loss of central and peripheral motor neurons, rapidly leading to major impairment/disability and ultimately to death. The median life expectancy after diagnosis is four years. ALS affects around 400,000 people worldwide. The only approved treatment (Riluzole) has a very limited impact on life expectancy and does not improve quality of life.
PXT864 is a novel synergistic combination of baclofen and acamprosate given as a pill twice a day. PXT864’s main mechanism of action is the restoration of balance between excitatory (glutamate activity) and inhibitory (glycine and GABA activity) pathways, disrupted by toxic factors such as Aβ oligomeric peptides in Alzheimer’s disease.
PXT864 showed positive safety and tolerability results in a Phase 1 clinical trial that enrolled 24 healthy volunteers.
PXT864’s most advanced indication is Alzheimer’s disease. An additional Phase 1 clinical trial, which enrolled 20 healthy volunteers, showed initial efficacy in a scopolamine dementia-induced model. A Phase 2a clinical trial was completed in 2015 in 45 patients with mild Alzheimer’s disease and positive encouraging results were obtained.
Further Phase 2 studies are planned for Alzheimer's disease, Parkinson’s disease and amyotrophic lateral sclerosis (ALS).
PLEODIAL™ : EXPLORATORY PHASE 2 STUDY OF PXT864 FOR THE TREATMENT OF ALZHEIMER’S DISEASE
The PLEODIAL trial was an exploratory multicenter single blind Phase 2 study that evaluated 3 doses of PXT864 in 45 patients with mild Alzheimer’s disease who were naïve to anti-dementia treatment: the first two doses were based on the same ratio of baclofen / acamprosate [dose 1 and 2] and the third dose used another ratio [dose 3]. The main objectives were to assess safety, compliance and preliminary efficacy on cognitive and behavioral impairment. The study was designed over a period of 36 weeks: “PLEODIAL-I” for the first 12 weeks followed by “PLEODIAL-II” for the remaining 24 weeks. During PLEODIAL-I, patients received PXT864 during the first 4 weeks (“challenge”) followed by 4 weeks of placebo (“de-challenge”) and then 4 weeks of PXT864 (“re-challenge”). During PLEODIAL-II, patients were invited to continue on PXT864 with the dose they had received during PLEODIAL-I. During the last 12 weeks of the study, physicians were authorized to co-administrate donepezil 5 mg with PXT864. In total, patients were treated with PXT864 for 32 out of 36 weeks in the PLEODIAL-I and II studies. This clinical trial was conducted in 7 French memory centers from February 2013 to December.
Data collected suggests that:
. PXT864 is well tolerated and safe for use in patients with AD
. PXT864 may slow the progression of cognitive disability in patients with mild AD
. PXT864 may be used concomitantly with low-dose donepezil treatment (5 mg daily).
These findings show promising efficacy of PXT864 to be further explored in future studies, such as an international multicenter adaptive-design Phase 2 study.