Session Title: Abstracts: Muscle Biology, Myositis & Myopathies (0441–0444)
Session Type: Abstract Session
Session Time: 9:00AM-9:15AM
Background/Purpose: Inclusion body myositis (IBM) is the most common idiopathic inflammatory myopathy occurring in patients over the age of 45 years. Since immune suppression has not been effective, modulating the cytoprotective “heat shock response” (HSR) represents a candidate therapeutic approach targeting both inflammation and degeneration. In a pilot study, arimoclomol, an amplifier of the HSR, was safe and well tolerated with some trends suggesting efficacy at 8 months in subjects with IBM. Our aim is to present the efficacy and safety/tolerability data from a phase 2/3 randomized controlled trial of arimoclomol in IBM (NCT02753530).
Methods: In this international multicenter, double-blind, placebo-controlled trial, subjects were randomized (1:1) to receive either arimoclomol citrate 400 mg or matching placebo capsules three times a day (1,200 mg/day) for 20 months. The primary outcome measure was the change from baseline to Month 20 in the IBM Functional Rating Scale (IBMFRS) total score. Hierarchically ordered key secondary outcome measures included hand grip strength (strongest hand), Modified Time Up and Go, Manual Muscle Testing (24 muscles), 6-minute walk test distance, and the Short-Form 36 health survey. Other outcome measures included patient and clinician impressions, and other measures of muscle strength and function. Drug safety and tolerability were evaluated.
Results: One hundred fifty-two IBM subjects fulfilling ENMC 2011 criteria were randomized with mean age 67.2 years (SD 8.1), mostly men (76%), mean disease duration 98 months (SD 58), and mean baseline IBMFRS of 27.4 (SD 4.6). The IBMFRS declined by a mean of 3.25 points with arimoclomol vs. 2.26 points with placebo over 20 months (p=0.11). Secondary efficacy outcome measures did not show any statistically significant treatment group differences. Most frequently reported AEs observed with higher incidence in arimoclomol group were gastrointestinal disorders (54.8% vs. 39.7%). Patients receiving arimoclomol were more likely to discontinue treatment due to AEs (17.8% vs. 5.1%). The relative frequency of serious AEs was comparable in the two treatment arms (arimoclomol 15.1% vs. placebo 23.1%). Elevated transaminases were reported in the first three months and were more frequently observed with arimoclomol than with placebo (15.4% vs. 6.4%).
Conclusion: This trial did not demonstrate a benefit of arimoclomol in IBM with respect to its primary and secondary efficacy endpoints.
To cite this abstract in AMA style:Machado P, Barohn R, McDermott M, Blaetter T, Lloyd T, Shaibani A, Freimer M, Amato A, Ciafaloni E, Jones S, Mozaffar T, Gibson S, Wicklund M, Levine T, Sundgreen C, Carstensen T, Bonefeld K, Jørgensen A, Phonekeo K, Heim A, Herbelin L, Hanna M, Dimachkie M. A Randomized, Double-blind, Placebo-controlled Study of Arimoclomol in Patients with Inclusion Body Myositis [abstract]. Arthritis Rheumatol. 2021; 73 (suppl 9). https://acrabstracts.org/abstract/a-randomized-double-blind-placebo-controlled-study-of-arimoclomol-in-patients-with-inclusion-body-myositis/. Accessed January 27, 2023.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-randomized-double-blind-placebo-controlled-study-of-arimoclomol-in-patients-with-inclusion-body-myositis/