Planning future clinical trials in Machado Joseph disease: Lessons from a phase 2 trial.

BACKGROUND: In a recent phase 2 clinical trial in spinocerebellar ataxia type 3/Machado Joseph disease (SCA3/MJD), a neurogenetic disorder without specific therapy, benefits of lithium carbonate were found only on secondary efficacy outcomes, all related to ataxic features. In order to help designing future studies, we further analyzed the trial data searching for treatment response modifiers and metric properties of spinocerebellar ataxia (SCA) scales. METHODS: Efficacy analysis was performed with the Neurological Examination Score for the Assessment of Spinocerebellar Ataxia (NESSCA) and the Scale for the Assessment and Rating of Ataxia (SARA) subscores and with the subgroup of patients with independent gait according to the 8-meter walking-time (8MW). Interactions of clinical/molecular findings with treatment response, minimally important differences (MIDs), and sample size estimations for NESSCA, SARA, Spinocerebellar Ataxia Functional Index (SCAFI) and Composite Cerebellar Functional Score (CCFS) were evaluated. RESULTS: 62 SCA3/MJD patients had been randomly assigned (1:1) for the double-blind, placebo-controlled trial. While cerebellar NESSCA (range: 0-7 points) differed between groups 0.64 points (95% CI 0.23 to 1.05, p<0.001) over the whole 48weeks of study, favoring lithium, no effect was found on non-ataxia subscores. Among patients able to perform the 8MW on baseline, NESSCA (p=0.010) and SCAFI (p=0.015) differed between groups favoring lithium. Finally, estimated sample sizes for the scales were provided. CONCLUSION: Lithium efficacy on cerebellar NESSCA, and on SCAFI and CCFS in the primary analysis, together with the lack of effect on non-ataxia features suggests that lithium should be tested in phase 3 trials in SCA3/MJD and that ataxia scales should be preferred to multisystem neurological instruments as the primary outcome. The inclusion of early stage patients is advisable in future clinical trials in SCA3/MJD. TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01096082.

A randomized, phase 2 clinical trial of lithium carbonate in Machado-Joseph disease.

BACKGROUND: Because lithium exerts neuroprotective effects in preclinical models of polyglutamine disorders, our objective was to assess the safety and efficacy of lithium carbonate (0.5-0.8 milliequivalents per liter) in patients with Machado-Joseph disease (spinocerebellar ataxia type 3 [MJD/SCA3]). METHODS: For this phase 2, single-center, double-blind, parallel, placebo-controlled trial (ClinicalTrials.gov identifier NCT01096082), 62 patients who had MJD/SCA3 with a disease duration ≤10 years and an independent gait were randomly assigned (1:1) to receive either lithium or placebo. RESULTS: After 24 weeks, 169 adverse events were reported, including 50.3% in the lithium group (P = 1.00; primary safety outcome). Sixty patients (31 in the placebo group and 29 in the lithium group) were analyzed for efficacy (intention-to-treat analysis). Mean progression between groups did not differ according to scores on the Neurological Examination Score for the Assessment of Spinocerebellar Ataxia (NESSCA) after 48 weeks (-0.35; 95% confidence interval, -1.7 to 1.0; primary efficacy outcome). The lithium group exhibited minor progression on the PATA speech-rate (P = 0.002), the nondominant Click Test (P = 0.023), the Spinocerebellar Ataxia Functional Index (P = 0.003), and the Composite Cerebellar Functional Score (P = 0.029). CONCLUSIONS: Lithium was safe and well tolerated, but it had no effect on progression when measured using the NESSCA in patients with MJD/SCA3. This slowdown in secondary outcomes deserves further clarification.

Progression rate of neurological deficits in a 10-year cohort of SCA3 patients.

Spinocerebellar ataxia 3 is an untreatable CAG repeat expansion disorder whose natural history is not completely understood. Our aims were to describe the progression of neurological manifestations in a long-term cohort of spinocerebellar ataxia 3, and to verify if CAG expanded repeat, gender, and age at onset were associated with the rate of progression. Patients entered the study between 1998 and 2005 and were seen until 2007. On each visit, the validated NESSCA scale, an inventory of 18 neurological manifestations, was applied. Scores observed in each year of disease duration produced a Growth Curve, which was analyzed through the random coefficients model. Scores obtained in some individual items were described through multi-state Markov models. One hundred fifty-six patients (78 families) were recruited; 28 were lost, and 23 died. Mean (sd) ages at onset and at baseline were 32.8 (10.6) and 40.7 (12.8) years; median (range) expanded CAGn was 74 (67-85). Three hundred fifteen NESSCA evaluations were performed, comprising disease durations from zero to 34 years. The 105 patients who completed the study were seen over 5 (sd = 2.4) years at intervals of 2.5 (sd = 1.5) years. The trajectory of NESSCA obtained for the overall group increased by 1.26 points per year. This slope increased by 0.15 points per each additional CAG in the expanded repeat (p < 0.0002) and decreased by 0.03 points per each additional year of age at onset (p = 0.005). NESSCA worsened steadily, producing linear trajectories, which were faster among patients with longer expanded repeats (>74) and with lower ages at onset (<34 years).