Two Parkinson’s patients treated with AXO-Lenti-PD, an investigative gene therapy, in an ongoing clinical trial continue to show improvement 12 months later, Axovant, the therapy’s developer, said in a release.
These findings at one year after treatment are important because this timepoint allows for a better assessment of therapy durability, and a more assured differentiation between placebo effects and therapeutic response, the company added.
AXO-Lenti-PD has shown encouraging results in these two people given a first low dose in the SUNRISE-PD (NCT03720418) Phase 1/2 clinical trial, which is now enrolling up to 30 patients at sites in France and England.
The treatment works by delivering three genes involved in dopamine production directly to the brain via a surgical procedure.
Dopamine is a neurotransmitter — a molecule involved in transmitting information between neurons — that is critical to coordinating movement. Dopamine-producing (dopaminergic) neurons are lost in Parkinson’s, and the resulting drop in dopamine levels is the cause of many disease symptoms.
By ‘infecting’ brain cells with the genetic instructions to increase dopamine production, AXO-Lenti-PD aims to turn other cells into dopaminergic neurons.
Current dopamine replacement therapies require continual oral doses of dopamine, whose effectiveness fades over time. The period between when one dose’s effectiveness wanes and the taking of a next dose can result in “off periods,” wherein patients report a return of symptoms such as poor motor control, stiffness, fatigue and mood changes.
Helping the brain to again produce adequate levels of dopamine would, in theory, eliminate the need for periodic oral doses, which could significantly limit off periods.
Previous studies in primate models of Parkinson’s found AXO-Lenti-PD to be safe and effective, and SUNRISE-PD results at three months’ post-treatment found that a one-time delivery of the therapy significantly improved patient scores on the Unified Parkinson’s Disease Rating Scale (UPDRS), a standard assessment of motor and non-motor symptoms associated with Parkinson’s.
The trial consists of two parts. Part A is an open-label, dose-escalation phase in which patients receive one of potentially three escalating doses of the gene therapy. In part B, a new group of patients will be randomized to either the ideal part A dose or to a sham procedure as an untreated control group. SUNRISE-PD’s goal is to test the safety, tolerability, and effectiveness of the potential treatment.
Both patients here, the first two enrolled, received the lowest dose (4.2×106 transducing units) of AXO-Lenti-PD.
One-year results show positive changes of 24 points and 20 points (respectively for the two patients) on the UPDRS Part III “Off” score, representing a 37% improvement in off-period motor symptoms, Axovant reported. Improvement at six months was 29%, as measured on the same scale.
These patients also showed an average 13-point positive change from baseline (study start) — representing a 44% improvement — on the UPDRS Part II “Off” score, which assesses daily life activities. On the PDQ-39 score index, another quality-of-life measure in Parkinson’s disease, these two showed an average 15-point positive change, or a 30% improvement from baseline to 12 months.
Both patients tolerated AXO-Lenti-PD well, and neither reported any serious side effects. One maintained a diary of on/off periods, which is useful in evaluating changes that might be due to therapy across time.
People being enrolled in SUNRISE-PD have had Parkinson’s for at least five years, have motor fluctuations and dyskinesia (jerky, involuntary movements), and are between the ages of 48 and 70. More information can be found here.
The company expects to soon release six-month results on the first two patients given a second and higher dose of AXO-Lenti-PD. This dose is three times higher than that given the first cohort.
If dose-escalation results allow, Axovant expects to begin the randomized and placebo-controlled part B of the SUNRISE-PD as a Phase 2 study by the close of 2020.
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