OBJECTIVES
sIBM is a progressive idiopathic inflammatory myopathy characterized by atrophy and weakness of proximal and distal muscle groups with the knee extensors and wrist/finger flexors frequently involved as well as dysphagic processes. Progressive weakness results in a loss of independence and the need for assistive devices and supportive care. While no pharmacological treatments for sIBM are currently marketed, clinical trials are underway. To assess the potential treatment benefit of new therapies and track clinical progression, a patient-reported measure (PROM) of physical function, the sIBM Physical Functioning Assessment (sIFA), was developed.
METHODS
The sIFA was rigorously developed in accordance with the FDA PRO Guidance. This included literature review, medical expert and direct patient input. A single-visit, observational study involving sequential concept elicitation and cognitive debriefing interviews was conducted. Standard qualitative analytical methods were employed to analyze interview data and generate and pilot-test questionnaire items.
RESULTS
Twenty concept elicitation and 19 cognitive debriefing interviews were conducted as well as consultation with six sIBM expert physicians. sIBM patients (n=39) varied in age (mean= 67; range 46-81), duration of diagnosis (1 – 18 years), and functional impairment. The resultant PROM consists of 11 items scored on a 0 (no difficulty) to 10 (unable to do) numerical rating scale. sIFA items are aligned with the functional impact of sIBM described in the literature/expert review and identified as relevant and important to sIBM patients. The draft conceptual framework includes items related to upper extremity, lower extremity, general function and swallowing. Cognitive testing of paper and ePRO versions support the use of this tool in a broad functional range of sIBM patients.
CONCLUSIONS
The sIFA is the first content valid tool developed specifically for use in the functional assessment of treatment benefit in sIBM patients aligned with the FDA PRO Guidance. Psychometric evaluation is underway.
