The post hoc analysis by Brenner et al. regarding plecanatide's efficacy in young adults offers a provocative look at how we might redefine clinical success in irritable bowel syndrome with constipation (IBS-C) trials. By evaluating a “trisymptom” composite endpoint—integrating abdominal pain, bloating, and complete spontaneous bowel movement (CSBM) frequency—the authors address a demographic (ages 18–40) that frequently identifies bloating as a primary driver of disability 1. This multidimensional approach is conceptually appealing. It mirrors the complex symptom burden seen in disorders of gut–brain interaction more closely than traditional measures. However, several methodological nuances deserve attention. First, this trisymptom endpoint remains exploratory and is not yet validated. These data come from pooled Phase 3 trials that were not originally powered for this specific age-restricted group. Because there was no adjustment for multiplicity in the various response thresholds, it is difficult to know if the results show a coherent “global” improvement for the patient or just a statistical correlation between symptoms. This distinction matters because the authors observed a “floor effect” in the mild bloating subgroup (baseline scores < 3.0). This suggests that while plecanatide works well for moderate-to-severe cases, the 0–10 Likert scale might not be sensitive enough for broader populations. Also, previous randomized trials show that abdominal symptoms and bloating respond quite differently across various pharmacologic therapies 2, 3. We must ensure that new composite endpoints align with, rather than obscure, established regulatory benchmarks. Current US Food and Drug Administration guidance still focuses on the two-symptom responder model of pain and CSBMs, with bloating labeled as a secondary measure 4. We need prospective validation of multisymptom composites against these standards to confirm their clinical value. This validation should ideally include health-related quality-of-life (HRQoL) metrics, which were missing here, to prove that statistical responders are truly feeling better in daily life. There is also the issue of generalizability. While focusing on adults ≤ 40 years is logical given the high prevalence of bloating in that group, global studies show that symptom burden varies a lot by sex and geography 5, 6. Since the study population was over 75% White and 80% female, we need more research to see if these priorities hold true in more diverse populations. Finally, these multisymptom endpoints might be very useful for patients with overlapping disorders of gut–brain interaction, where symptom clustering is the main cause of impairment 7. In summary, this study provides useful exploratory data on plecanatide in a demographic that is often understudied. Strengthening these findings will require prospective validation of the trisymptom endpoint, focusing on clinical coherence and real-world quality-of-life impact. The author has nothing to report. The author has nothing to report. The author declares no conflicts of interest. Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.
Fariha Shahid Tanveer (Thu,) studied this question.