A Phase III, Double-Blind, Randomized, Multicenter, Clinical Trial to Evaluate the Efficacy and Safety of a Fixed-Dose Combination of Metformin Hydrochloride and Myo-Inositol Compared to Metformin in Patients With Polycystic Ovary Syndrome

Background Polycystic ovary syndrome (PCOS) poses a significant health concern among reproductive-aged women and is characterized by ovarian dysfunction, hyperandrogenism, and insulin resistance. This study aims to assess the efficacy and safety of metformin and myo-inositol combination therapy compared to metformin monotherapy in patients with PCOS. Materials and methods This was a phase III, double-blind, randomized controlled clinical trial. A total of 196 patients with PCOS were randomized in a 1:1 ratio to receive either a fixed-dose combination of metformin hydrochloride 500 mg and myo-inositol 600 mg (Met-Myo) or metformin 500 mg alone (Met) twice daily for 24 weeks. The primary study endpoints were improvement in insulin resistance (homeostatic model assessment of insulin resistance, HOMA-IR) at week 24 and improvement in menstrual cycle disturbances at 12 and 24 weeks. Results The Met-Myo combination demonstrated a significantly superior response with 63 (75%) patients showing improvement in HOMA-IR compared to 54 (60.67%) in the Met group (p = 0.049) at week 24. The improvement in the number of patients with heavy menstrual blood flow (>80 mL) was significantly greater in the Met-Myo group (four patients, 4.76%) compared to the Met group (six patients, 6.74%) at week 24 (p = 0.029). Improvement in the percentage of patients with normal menstrual frequency and infrequent menstruation from baseline to week 24 was significantly greater in the Met-Myo group compared to the Met group (p = 0.049). Safety assessments revealed a low and comparable incidence of mild adverse events. Conclusion Metformin-myo-inositol combination therapy is superior to metformin monotherapy in addressing menstrual irregularities and improving insulin resistance in PCOS patients, thereby providing a promising avenue for optimizing the management of PCOS.