However, at least one expert believes the study has “significant flaws.”
Investigators randomly assigned 20 individuals with sporadic ALS to receive either ropinirole or placebo for 24 weeks. During the double-blind period, there was no difference between the groups in terms of decline in functional status.
However, during a further open-label extension period, the ropinirole group showed significant suppression of functional decline and an average of an additional 7 months of progression-free survival.
The researchers were able to predict clinical responsiveness to ropinirole in vitro by analyzing motor neurons derived from participants’ stem cells.
“We found that ropinirole is safe and tolerable for ALS patients and shows therapeutic promise at helping them sustain daily activity and muscle strength,” first author Satoru Morimoto, MD, of the department of physiology, Keio University School of Medicine, Tokyo, said in a news release.
The study was published online in Cell Stem Cell.
Feasibility study
“ALS is totally incurable and it’s a very difficult disease to treat,” senior author Hideyuki Okano, MD, PhD, professor, department of physiology, Keio University, said in the news release.
Preclinical animal models have “limited translational potential” for identifying drug candidates, but induced pluripotent stem cell (iPSC)–derived motor neurons (MNs) from ALS patients can “overcome these limitations for drug screening,” the authors write.
“We previously identified ropinirole [a dopamine D2 receptor agonist] as a potential anti-ALS drug in vitro by iPSC drug discovery,” Dr. Okano said.
The current trial was a randomized, placebo-controlled phase 1/2a feasibility trial that evaluated the safety, tolerability, and efficacy of ropinirole in patients with ALS, using several parameters:
- The revised ALS functional rating scale (ALSFRS-R) score.
- Composite functional endpoints.
- Event-free survival.
- Time to ≤ 50% forced vital capacity (FVC).
The trial consisted of a 12-week run-in period, a 24-week double-blind period, an open-label extension period that lasted from 4 to 24 weeks, and a 4-week follow-up period after administration.
Thirteen patients were assigned to receive ropinirole (23.1% women; mean age, 65.2 ± 12.6 years; 7.7% with clinically definite and 76.9% with clinically probable ALS); seven were assigned to receive placebo (57.1% women; mean age, 66.3 ± 7.5 years; 14.3% with clinically definite and 85.7% with clinically probable ALS).
Of the treatment group, 30.8% had a bulbar onset lesion vs. 57.1% in the placebo group. At baseline, the mean FVC was 94.4% ± 14.9 and 81.5% ± 23.2 in the ropinirole and placebo groups, respectively. The mean body mass index (BMI) was 22.91 ± 3.82 and 19.69 ± 2.63, respectively.
Of the participants,12 in the ropinirole and six in the control group completed the full 24-week treatment protocol; 12 in the ropinirole and five in the placebo group completed the open-label extension (participants who had received placebo were switched to the active drug).
However only seven participants in the ropinirole group and one participant in the placebo group completed the full 1-year trial.