Table 3. Final top response criteria for minimal, moderate, and major improvement in JDM and combined adult DM/PM and JDM clinical trials and studies.
| Conjoint analysis–based continuous response criteria using absolute percent change in core set measures | ||
|---|---|---|
|
| ||
| Core Set Measure* | Level of Improvement | Level Score |
| Physician Global Activity | Worsening to 5% improvement | 0 |
| >5% to 15% improvement | 7.5 | |
| >15% to 25% improvement | 15 | |
| >25% to 40% improvement | 17.5 | |
| >40% improvement | 20 | |
|
| ||
| Parent Global Activity | Worsening to 5% improvement | 0 |
| >5% to 15% improvement | 2.5 | |
| >15% to 25% improvement | 5 | |
| >25% to 40% improvement | 7.5 | |
| >40% improvement | 10 | |
|
| ||
| MMT or CMAS | Worsening to 2% improvement | 0 |
| >2% to 10% improvement | 10 | |
| >10% to 20% improvement | 20 | |
| >20% to 30% improvement | 27.5 | |
| >30% improvement | 32.5 | |
|
| ||
| CHAQ | Worsening to 5% improvement | 0 |
| >5% to 15% improvement | 5 | |
| >15% to 25% improvement | 7.5 | |
| >25% to 40% improvement | 7.5 | |
| >40% improvement | 10 | |
|
| ||
| Enzyme (most abnormal) or CHQ-PhS | Worsening to 5% improvement | 0 |
| >5% to 15% improvement | 2.5 | |
| >15% to 25% improvement | 5 | |
| >25% to 40% improvement | 7.5 | |
| >40% improvement | 7.5 | |
|
| ||
| Extramuscular activity or Disease Activity Score | Worsening to 5% improvement | 0 |
| >5% to 15% improvement | 7.5 | |
| >15% to 25% improvement | 12.5 | |
| >25% to 40% improvement | 15 | |
| >40% improvement | 20 | |
|
| ||
| Improvement category | Total improvement score† | |
|
| ||
| JDM thresholds | Minimal | ≥30 |
| Moderate | ≥45 | |
| Major | ≥70 | |
|
| ||
| Adult DM/PM thresholds | Minimal | ≥20 |
| Moderate | ≥40 | |
| Major | ≥60 | |
Abbreviations: JDM, juvenile dermatomyositis; DM, dermatomyositis; PM, polymyositis; MMT, manual muscle testing; CMAS, Childhood Myositis Assessment Scale; CHAQ, Childhood Health Assessment Questionnaire; Enzyme, most abnormal serum muscle enzyme level among creatine kinase, aldolase, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase; CHQ-PhS, Physical Summary Score of the Child Health Questionnaire-Parent Form 50.
Note that either all the IMACS or all the PRINTO core set measures may be used.
Note that this response criteria is also proposed for use in combined adult DM/PM and JDM clinical trials (22).
How to calculate the Improvement Score: The absolute percent change (final value – baseline value / range) × 100 is calculated for each core set measure. For muscle enzymes, the most abnormal enzyme at baseline is used. The enzyme range was calculated based on 90% range of enzymes from natural history data (5;36), which for creatine kinase is 20 times the upper limit of normal (ULN), for aldolase is 6 times the ULN, and for lactate dehydrogenase, aspartate aminotransferase, and alanine transaminase is 5 times the ULN. An Improvement Score is assigned for each core set measure based on the absolute percent change. These are totaled among the six IMACS or PRINTO core set measures. The thresholds for minimal, moderate, and major improvement are provided. The Total Improvement Scores may also be compared among treatment arms in a trial. A Total Improvement Score between 0 and 100 also corresponds to the degree of improvement, with higher scores corresponding to a higher magnitude of improvement.