We hypothesized that DSP‐6952, a partial agonist of the 5‐hydroxytryptamine type‐4 receptor and a gastrointestinal prokinetic agent, can induce natural bowel movements by enhancing gastrointestinal motility and colonic transit in patients with chronic constipation and irritable bowel syndrome with constipation. This 3‐part phase 1 study evaluated the safety, tolerability, and pharmacokinetic and pharmacodynamic profiles of DSP‐6952. Eighty‐eight Japanese subjects (64 healthy volunteers and 24 subjects with spontaneous bowel movements ≤3 times/wk) were randomized to DSP‐6952 or placebo. The overall incidence of treatment‐emergent adverse events (TEAEs) was similar for DSP‐6952 and placebo. The most frequent TEAEs were gastrointestinal disorders; diarrhea was more common with DSP‐6952, but only when it was administered to healthy volunteers. Peak plasma concentration (Cmax) and area under the concentration‐time curve (AUC) of DSP‐6952 were dose‐proportional within a range of 4‐120 mg. Under fed conditions, the Cmax and AUC of DSP‐6952 were approximately half those of fasting conditions. No abnormal drug accumulation was observed with repeated administration. In subjects with spontaneous bowel movements ≤3 times/wk, the median change in the frequency of bowel movements from baseline increased, although the difference did not reach statistical significance. DSP‐6952 was well tolerated at single and multiple doses up to 120 mg/d, with a linear pharmacokinetic profile among all subjects.

Imeglimin is a diabetic drug excreted mainly in the urine; therefore, the impact of renal impairment on its pharmacokinetics (PK) is of interest. We assessed the PK and safety of imeglimin in Japanese patients with impaired renal function. This was an uncontrolled, open-label, single-dose, phase 1 study. Participants were classified into 4 groups by their estimated glomerular filtration rate (mL/min/1.73 m 2 ) as follows: ≥90, normal renal function; and 60 to <90, mild; 30 to <60, moderate; and 15 to <30, severe renal impairment. All participants received imeglimin 1000 mg except those with severe renal impairment, who received imeglimin 500 mg. PK parameters were estimated using noncompartmental analysis, and those after multiple administrations were projected using a noncompartmental superposition method. In total, 24 Japanese participants (6 in each group) were enrolled and completed the study.The mean plasma imeglimin concentration reached the maximum at 2-4 hours after administration and then rapidly decreased.The geometric mean maximum observed plasma concentration and area under the plasma concentration-time curve values were higher in the impaired renal function groups versus normal renal function group. Most imeglimin was excreted in urine by 24 hours after administration. Renal clearance decreased with decreasing renal function. Projected maximum observed plasma concentration and area under the plasma concentration-time curve over the dosing interval after multiple dosing were greater in the renal impairment groups versus normal renal function group. No adverse events were observed. Considering increased plasma exposure along with decreased renal clearance, dose adjustment is required in patients with moderate and severe renal impairment with estimated glomerular filtration rate of 15 to <45 mL/min/1.73 m 2 .