Oral mannitol for chemotherapy-induced constipation (CIC): A randomized, multicenter, controlled study.

12146 Background: Chemotherapy-induced constipation (CIC) is a common yet frequently overlooked supportive care issue, currently, there is still a lack of efficient and affordable methods. This trial was designed to compare the efficacy and safety of orally administered mannitol injection versus lactulose in cancer patients with CIC. Methods: An open-label, multicenter, prospective RCT (ChiCTR2200056847) planned to enroll 114 adults. Participants were randomized 1:1 to oral mannitol 50 mL post-meal 3–5×/day or lactulose 30 mL once daily for 3 days. Primary endpoint: time to first spontaneous defecation (TFSD). Secondary endpoints included weekly complete spontaneous bowel movements (CSBMs), Bristol Stool Form Scale, PAC-QOL, and CTCAE v5.0 adverse events (AEs). Interim analysis was performed when 112 participants had completed the 7-day assessment; database was locked on 30 January 2026. Results: A nationwide survey (14 provinces, n=1,174) revealed significantly higher constipation rates in stage IV cancer patients (p<0.05), and found that the managements vary in effectiveness. In an RCT interim analysis (112 patients), baseline demographics were balanced between mannitol (n=56) and lactulose (n=56) groups. Median time to first defecation was significantly shorter in mannitol group with 5.5 hours (IQR 3.0-15.8) than in lactulose with 16.0 hours (IQR 5.3-27.5) (p=0.003)(Fig. 1). Secondary outcomes were comparable: weekly mCSBMs (3.0 vs. 3.0, p=0.083); Bristol Scale improvement ≥1 category (60.7% vs. 58.9%, p=0.847); and PAC-QOL score (-26 vs. -18 points, p=0.105). Both treatments were safe, with only mild, transient adverse events at similar rates (3.6% vs. 5.4%, p=0.647)(Table 1). Conclusions: Survey data confirm under-recognition of CIC and therapeutic gaps for advanced-stage patients. In this interim analysis, oral mannitol significantly shorten TFSD than lactulose, with mild adverse events, which is a rapid-onset, low-cost option for CIC management. Clinical trial information: ChiCTR2200056847. TFSD, weekly CSBMs, adverse events, PAC-QOL. Outcome Mannitol (n=56) Lactulose (n=56) p-value TFSD (median, IQR) 5.5 (3.0–15.8) hrs 16.0 (5.3–27.5) hrs 0.003 Weekly CSBMs (median, IQR) 3.0 (3.0–4.0) 3.0 (2.0–3.0) 0.083 Stool form improvement (≥1 Bristol) 34 (60.7%) 33 (58.9%) 0.847 PAC-QOL change (Δ, mean) -26 (18.3–40.5) -18 (12.5-37.5) 0.105 Any AE (%) 2 (3.6%) 3 (5.4%) 0.647