Mallinckrodt has announced that it is permanently discontinuing its Phase IIb study designed to assess the efficacy and safety of Acthar Gel as an investigational treatment for amyotrophic lateral sclerosis (ALS).

The company made the decision to halt the trial after careful consideration of a recent recommendation by the study's independent Data and Safety Monitoring Board (DSMB), which was created by the company following industry best practice to ensure the safety of patients participating in a clinical study.

The reasons for halting the trial were cited as specific concern for pneumonia, which occurred at a higher rate in the ALS patients receiving Acthar Gel compared to those on placebo; the board also mentioned other adverse events specific to this patient population.

The DSMB noted the proportion of patients who have completed week 36 – the primary endpoint target – precludes a definitive determination of a treatment effect. The lack of a clear efficacy signal for this ALS patient population combined with the potential risk of pneumonia led to the board's recommendation.

"Mallinckrodt's primary focus is on the safety of patients and, while ALS patients are among those most in need of new therapies and treatment options, we believe this is the right decision. It is critical to stress, however, that these findings do not impact the current positive benefit/risk profile of Acthar for use in current on-label indications," said Steven Romano, executive vice president and chief scientific officer at Mallinckrodt.

He continued, "Though the probability of success for the ALS population was acknowledged as being low, this study was initiated based on compelling analyses carried out following the completion of a small pilot study and we were hopeful it would have translated into a benefit for this group of patients in great need of effective therapies. We thank the DSMB, the investigators and the patients who participated in the study."

ALS is a progressive neurodegenerative disease that affects motor neuron cells in the brain and the spinal cord. Motor neurons reach from the brain and the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise and when the motor neurons die, voluntary and involuntary muscle movement is lost.

With the progressive loss of motor neurons, people with ALS may lose the ability to speak, eat, move and breathe.