Introduction In 2 Phase 3 trials in irritable bowel syndrome with constipation (IBS-C) (Trial 31, Trial 302), linaclotide 290 μg once-daily (Constella^®; LIN) treatment was superior to placebo (PBO) based on European Medicines Agency co-primary endpoints (rate of abdominal pain/discomfort responders [Trial 31: 54.8% vs 41.8%; Trial 302: 54.1% vs 38.5%; P < 0.001]; IBS degree-of-relief responders [Trial 31: 37.0% vs 18.5%; Trial 302: 39.4% vs 16.6%; P < 0.0001]). A potential association between baseline patient characteristics and likelihood of therapeutic response to LIN is unclear.

Method This pooled analysis evaluated potential predictive value of baseline characteristics in 2 pivotal Phase 3 trials in IBS-C by comparing demographics and baseline symptoms (Table) for LIN 12-week non-responders vs responders, defined as: 1) abdominal pain/discomfort responders (≥30% reduction in abdominal pain and/or discomfort score [11-point scales], with neither worsening from baseline, for ≥6/12 weeks) and 2) IBS degree-of-relief responders (symptoms ‘considerably’ or ‘completely’ relieved for ≥6/12 weeks).

Results The pooled analysis included 1602 patients (LIN, n = 805; PBO, n = 797). Baseline characteristics were similar for responders and non-responders in the LIN and PBO groups for both endpoints (Table 1). Abdominal discomfort scores and body mass index were also similar for responders and non-responders (not shown).

Conclusion The baseline demographics and disease characteristics analysed did not predict treatment response to LIN or PBO in patients with IBS-C in the Phase 3 pivotal trials.

Disclosure of interest C. Díaz Employee of: Almirall S. A., M. Falques Employee of: Almirall S. A., D. Vilardell Employee of: Almirall S. A., J. Fortea Employee of: Almirall S. A., J. Johnston Employee of: Ironwood Pharmaceuticals.