New data regarding the treatment of chronic inflammatory demyelinating polyneuropathy (CIDP) offers clinicians a clearer look at long-term patient outcomes. A post hoc analysis of the ADHERE and ADHERE+ studies examined how disability levels change over time for patients taking subcutaneous efgartigimod PH20 (Vyvgart Hytrulo). The findings were presented recently at the 2026 Peripheral Nerve Society Annual Meeting. This analysis is part of a NeurologyLive® Special Report which explores how additional data regarding the medication can help clinicians better interpret long-term functional outcomes in patients with CIDP, providing a deeper understanding of the treatment’s impact beyond initial trial results.
While primary endpoints often determine whether a clinical trial meets its objectives, secondary and post hoc analyses frequently provide the clinical context that physicians need to apply those findings in practice. For this specific condition, understanding how disability changes over time may be just as important as knowing whether a relapse is prevented. Neurologists Karissa Gable, MD, FAAN, professor of neurology at Duke University, and Jeffrey Allen, MD, associate professor of neurology at the University of Minnesota, examined the data to help clinicians better interpret these functional outcomes. Their discussion highlights why sustained reductions in disability may represent an important benchmark when evaluating treatment success, focusing on the value added by these additional investigations.
The primary outcome measure in the ADHERE trial was relapse, defined by changes in the INCAT score during the randomized Stage B portion of the study which compared patients who remained on treatment with those who discontinued it. Following that randomized placebo-controlled phase, patients were permitted to enter an open label extension and were followed for an additional 36 weeks. Throughout the study, including before enrollment, during the open label Stage A, the randomized Stage B, and the open label extension, INCAT scores were collected at each stage to track functional status. This full collection allowed for a detailed review of changes in INCAT scores throughout the different phases of the trial.
Related: Sorry, You Have Been Blocked
Observations indicated that INCAT scores improved during the open label Stage A while all patients were receiving efgartigimod. In contrast, during Stage B, patients who were randomized to placebo lost some of that improvement, whereas those who remained on efgartigimod maintained their gains. Once the entire group entered the open label extension and resumed efgartigimod, patients who had previously received placebo improved to a level similar to those who had remained on active treatment throughout the study. Additionally, patients who stayed on efgartigimod continuously continued to maintain those improvements over the duration of the follow-up period.
Evaluating the entire study population from the time patients entered the trial while receiving their background therapy through the end of the extension study, the overall improvement in INCAT score was approximately 1.2 points. This demonstrates a clinically meaningful improvement among patients who initially responded to efgartigimod during Stage A. It is important not to overinterpret these findings as a direct comparison with background therapies because there are details unknown about those treatments; however, the analysis gives confidence that patients have the capacity to continue improving over as long as 36 weeks. Furthermore, it provides key information about durability, specifically that patients who respond tend to maintain that response over time.
Karissa Gable, MD, FAAN, noted that as the weeks progressed, the proportion of responders who either maintained their response or achieved an INCAT score of 1 or lower continued to increase. Ultimately, about one-third of Stage A responders reached an INCAT score of 1 or less at some point during the study. Investigators also examined durability closely, finding that among the 77 of 196 patients who maintained a response across at least two consecutive visits, 80.5% achieved an INCAT score of 1 or less. Looking at patients who maintained that response across three or more consecutive visits, 70.1% of those 77 patients still had an INCAT score of 1 or less after 24 weeks. These findings reinforce the durability of the treatment response over time, offering a robust picture of long-term patient management.