Are few selected measures more relevant than multiple measures?

The choice of a primary endpoint in therapeutic trials is critical for patients, researchers, pharmaceutical companies and investors but, not for the same reasons. This decision may lead to a trial failure/success purely based on the selection of the primary criterion itself. Studies on disease natural history seek to assist the sponsor in making this crucial choice.

Sangha et al1 report important information in a natural history study of the largest cohort studied up until now, of patients with inclusion body myositis (IBM), the most prevalent inflammatory disease of the muscle, in older adults. This study is a useful and impressive extension of a work by the same team, published in 2013.2 Manual muscle testing (MMT) of 23 muscle groups, bilaterally and fixed dynamometry (termed here as Quantified Muscle Testing: QMT) of six muscle groups, bilaterally were used to assess patients’ strength and, the IBM Functional Rating Scale (IBMFRS) was used to evaluate function. Judiciously, MMT scores were summed before being expressed as a percentage of maximal possible …