Abstract Background Biologics are used to induce clinical remission in individuals with active Crohn’s disease (CD), but around 50-60% of patients achieve clinical remission. Exclusive enteral nutrition is also an effective induction treatment, but tolerability limits its use, especially in adults. This study aimed to assess the efficacy of partial enteral nutrition (PEN) in combination with adalimumab (ADA) compared to ADA monotherapy. Methods Adults with active CD (CDAI150) starting ADA were randomised to replace half of their diet with Modulen-IBD (ADA+PEN) for six weeks or to continue their habitual diet (ADA). The primary outcome was to compare response (CDAI decrease≥70) and remission rates (CDAI150) between ADA+PEN and ADA at week-12. PEN adherence was assessed with three approaches. Calprotectin (FCAL), CRP, SIBDQ, drug levels and antibodies were measured at baseline, week-6 and week-12. In a subset of patients ileocolonoscopy (SES-CD scoring) was performed at baseline and week-12. Data presented as intention-to-treat analysis. Results 101 patients recruited (51 ADA+PEN, 50 ADA). PEN adherence was high (81%). Clinical response and remission rates at week 12 were similar between the two groups (response; ADA+PEN 67%, vs ADA 65%, p = 0.86, remission; ADA+PEN 51% vs ADA 54%, p = 0.79). FCAL, CRP, and SIBDQ improved but did not differ between groups. At week-12, a higher volume of PEN consumed was associated with a lower CDAI at week-12 (CDAI; rho=-0.35, p = 0.02). ADA+PEN patients with FCAL≥100mg/kg and CRP≥5mg/L, at baseline, had a higher rate of clinical response at week-6 (ADA+PEN, 96% vs ADA, 65%, p = 0.01) but not at week-12 (p = 0.08). In patients with ileal disease, ADA+PEN had a lower median CDAI at week-6 (ADA+PEN, 71 vs ADA, 149, p = 0.039). Sixteen patients had endoscopies; 86% in ADA+PEN achieved a 50% SES-CD decrease compared with 33% in ADA (p = 0.03, Figure 1A). Drug levels were similar in the two groups at week-6 and 12. More patients developed drug antibodies in ADA (ADA+PEN vs ADA; week-6: 0%, vs 3%, week-12: 7% vs 16%; p = 0.123 across all timepoints, Figure 1B). Conclusion Addition of PEN to ADA is beneficial in those with a greater inflammatory burden and with ileal disease. It is also associated with increased rates of mucosal endoscopic response and with fewer patients forming anti-drug antibodies during induction treatment. Conflict of interest: White, Bernadette: Studentship paid for by Nestle Health Science and the University of Glasgow. Previous travel support also from Nestle Health Science. Campbell, Iona: No conflict of interest Fandinga, Catarina: Previous travel support also from Nestle Health Science Kerbiriou, Caroline: No conflict of interest Clowe, Jennifer: No conflict of interest Jatkowska, Aleksandra: Studentship paid for by Nestle Health Science and the University of Glasgow. Previous travel support also from Nestle Health Science. Brownson, Emily: No conflict of interest Milling, Simon: No conflict of interest Ho, Gwo-Tzer: None Mowat, Craig: No conflict of interest Robertson, Elaine: No conflict of interest Gaya, Daniel: No conflict of interest Kefayat, Amirhosein: No conflict of interest Din, Shahida: No conflict of interest Seenan, John Paul: No conflict of interest Macdonald, Jonathan: None to declare Gerasimidis, Konstantinos: Grant: Nestle Health Science, Nutricia-Danone, Mylan Personal Fees: Abbott, Baxter, Nestle Health Science, Nutricia-Danone, Servier, Janssen
White et al. (2026) studied this question.