Arimoclomol Shows No Benefit for Inclusion Body Myositis

Oral arimoclomol had no benefit over placebo in patients with inclusion body myositis, according to a study published in The Lancet Neurology. The clinical trial follows numerous others finding a lack of efficacy with investigational therapies for inclusion body myositis.

“With arimoclomol, we assessed the alternative strategy of augmenting the heat shock response, which is hypothesized to improve protein degradation pathways and consequently reduce cell stress,” wrote corresponding author Pedro M. Machado, MD, PhD, of University College London in the United Kingdom, and study coauthors. “However, this drug also did not show clinical efficacy in individuals with inclusion body myositis with the chosen dose.”

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The double-blind, randomized controlled trial included 150 adults with inclusion body myositis from 11 neuromuscular clinics in the United States and 1 in the United Kingdom. Among them, 73 were randomized to oral arimoclomol 400 mg and 77 to placebo 3 times daily for 20 months.

The average change from baseline to month 20 in the Inclusion Body Myositis Functional Rating Scale total score did not differ significantly between the arimoclomol (–3.26) group and the placebo group (–2·26), according to the study.

Among the 150 participants randomized and included in the efficacy analysis, 126 finished all 20 months of the trial. Rates of completion were 77% in the arimoclomol group and 90% in the placebo groups. The most common reason for discontinuation was adverse events.

Serious adverse events affected 15% of patients in the arimoclomol group and 23% in the placebo group, researchers reported. Rates of elevated transaminases 3 times or more of the upper limit of normal were 7% with arimoclomol and 1% in with placebo. One patient in the arimoclomol group experienced tubulointerstitial nephritis.

“Arimoclomol did not improve efficacy outcomes, relative to placebo, but had an acceptable safety profile in individuals with inclusion body myositis,” researchers wrote. “This is one of the largest trials done in people with inclusion body myositis, providing data on disease progression that might be used for subsequent clinical trial design.”

Reference

Machado PM, McDermott MP, Blaettler T, et al. Safety and efficacy of arimoclomol for inclusion body myositis: a multicentre, randomised, double-blind, placebo-controlled trial. Lancet Neurol. 2023;22(10):900-911. doi:10.1016/S1474-4422(23)00275-2