Comparative effectiveness of metformin monotherapy in extended release and immediate release formulations for the treatment of type 2 diabetes in treatment-naïve Chinese patients: Analysis of results from the CONSENT trial

Bioequivalence of Related GelShieldⓇ Sustained-release Formulations of Metformin: A Pooled Pharmacokinetic Analysis

PURPOSE

GlucophageⓇ (Merck Healthcare KGaA, Darmstadt, Germany) is the originator brand of metformin hydrochloride, an oral antidiabetic drug. Metformin is recommended in guidelines as first-line treatment of type 2 diabetes mellitus and increasingly in related insulin-resistant conditions, such as prediabetes and polycystic ovary syndrome. The GelShieldⓇ sustained-release formulation tablet of GlucophageⓇ has been improved from the historic version marketed in 2000. Bioequivalence has been demonstrated stepwise along this evolution; however, a head-to-head evaluation between the initial and the current version is missing. This analysis aims to close this gap and to determine bioequivalence between related originator GelShieldⓇ sustained-release formulations of metformin, GlucophageⓇ (GXR 500 mg), from Europe and the United States.

METHODS

Data from seven randomized crossover bioequivalence studies in 361 healthy participants of Asian and non-Asian ethnicity from Europe, the United States, and Asia were considered. All evaluated a single oral dose of 500 mg of the test and reference formulation in healthy male and female participants in fed and fasted state. Bioequivalence was evaluated by means of a combined bridging analysis of available data on the current round tablet from Europe (rGXR EU) and the historic oblong tablet from the United States (oGXR US) in healthy Asian and non-Asian participants under fed and fasting conditions. Bioequivalence between the two formulations was assessed statistically with a mixed effects model for AUC0-t, Cmax, and AUC0-inf.

FINDINGS

In all studies, bioequivalence between the respective test and reference formulations of GXR was shown. Statistical analysis of pooled pharmacokinetic data of 2 (primary pooling set) or 3 studies (secondary pooling set) demonstrated bioequivalence between rGXR EU and oGXR US via bridging with oGXR EU. The 90% CI for the geometric mean ratio of all pharmacokinetic parameters was within the bioequivalence range of 0.80 to 1.25. In the primary pooling set, geometric least squares mean ratios in the fed group ranged from 0.9931 (90% CI, 0.9151-1.0778) for AUC0-inf to 1.1344 (90% CI, 1.0711-1.2014) for Cmax; results in the fasted group were similar. The secondary pooling set, which added a study in Asians, confirmed these findings.

IMPLICATIONS

Bioequivalence was determined between sustained-release formulations of GlucophageⓇ from Europe and the United States under fasted and fed conditions in healthy men and women, including different ethnicities. The efficacy and safety of GlucophageⓇ XR can be claimed along the evolution from oGXR US, via oGXR EU to rGXR EU, and in several ethnicities and production sites.

Insights Into Metformin XR Pharmacotherapy Knowledge Among Community Pharmacists: A Cross-Sectional Study

Background

There is a little knowledge on the extent to which healthcare providers understand and accept the professional recommendations and appropriate dosing strategy regarding metformin XR.

Objectives

To evaluate UAE community pharmacists' knowledge, attitude, and practices (KAP) concerning metformin XR.

Methods

This is a cross-sectional research study conducted amongst licensed community pharmacists. The survey took place via a questionnaire and physical interviews were held. The survey used in this study included questions on demographics and questions on the participants' attitudes, knowledge and practices concerning metformin XR. The factors influencing KAP regarding metformin XR were examined via simple logistic regression analysis.

Results

Threehundred fifty-three (n = 353) participants were recruited in the study. Independent pharmacies constituted 57.5% of this study sample and 42.5% were chain pharmacies. The average knowledge score about metformin XR tablets was 42.5% with a confidence interval (CI) of 95% [37.3%, 47.4]. Better knowledge scores on metformin XR tablets was observed in respondents aged ⩾40 years (OR 2.97, 95% CI 1.63-5.4), having greater than 10 years in terms of experience (OR 2.28; 95% CI 1.25-4.16) and pharmacist graduated from Regional or international universities (OR 2.08; 95% CI 1.34-3.24). About 78% (n = 275) of the participants believed that metformin XR tablets have better efficacy and 63.2% (n = 233) indicated that metformin IR was associated with greater adverse effects.

Conclusion

This study demonstrated a distinct gap in knowledge, attitude and practice pertaining to metformin XR among community pharmacists in the UAE. The community pharmacists need to enhance their practice by receiving accurate and reliable data to support their decision-making on the prescribing of metformin XR. The implementation of novel guidelines and evidence dissemination strategies may help bridge this gap.

Extended-release metformin improves cognitive impairment in frail older women with hypertension and diabetes: preliminary results from the LEOPARDESS Study

BACKGROUND

Women have a high risk of frailty independently of age and menopause state. Diabetes and hypertension increase the risk of frailty and cognitive impairment. Metformin has been employed in post-menopausal women and some reports have shown encouraging effects in terms of attenuated frailty. However, the impact on cognitive performance of a recently introduced extended-release formulation of metformin has never been explored.

METHODS

We studied consecutive frail hypertensive and diabetic older women presenting at the ASL (local health authority of the Italian Ministry of Health) Avellino, Italy, from June 2021 to August 2022, who were treated or not with extended-release metformin. We included a control group of frail older males with diabetes and hypertension treated with extended-release metformin and a control group of frail older women with diabetes and hypertension treated with regular metformin.

RESULTS

A total of 145 patients successfully completed the study. At the end of the 6-month follow-up, we observed a significantly different cognitive performance compared to baseline in the group of frail women treated with extended-release metformin (p: 0.007). Then, we compared the follow-up groups and we observed significant differences between frail women treated vs. untreated (p: 0.041), between treated frail women and treated frail men (p: 0.016), and between women treated with extended-release metformin vs. women treated with regular metformin (p: 0.048). We confirmed the crucial role of extended-release metformin applying a multivariable logistic analysis to adjust for potential confounders.

CONCLUSIONS

We evidenced, for the first time to the best of our knowledge, the favorable effects on cognitive impairment of extended-release metformin in frail women with diabetes and hypertension.

Metformin extended-release versus metformin immediate-release for adults with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

AIM

To compare the efficacy and tolerability of metformin extended-release (MXR) and the conventional metformin immediate-release (MIR) formulations in adults with type 2 diabetes mellitus (T2DM) METHODS: PubMed, the Cochrane Library, ClinicalTrials.gov and other sources were searched until 19 March 2021 for randomized controlled trials (RCTs) that compared equal daily doses of MXR and MIR in adults with T2DM. Random-effects model meta-analysis was performed to obtain pooled mean difference (MD) of change from baseline for continuous outcomes and risk ratio (RR) for dichotomous outcomes. Primary outcomes considered were HbA1c and key gastrointestinal (GI) symptoms (abdominal discomfort or pain, diarrhea, dyspepsia, and nausea & vomiting).

RESULTS

Nine RCTs that randomized a total of 2609 adults revealed that MIR was statistically associated with better HbA1c lowering (MD 0.09% [95% confidence interval or CI, 0.01%, 0.17%]), MXR only reduced dyspepsia (RR 0.58 [95% CI, 0.34, 0.98]), and both formulations were associated with similar cumulative incidence of other key GI symptoms.

CONCLUSIONS

MXR was associated with statistically worse but likely clinically similar HbA1c lowering and minimal improvement of GI intolerance compared to MIR. Protocol Registration: PROSPERO (CRD42019148008).

Knowledge, Attitude, and Practice of Metformin Extended-Release Tablets Among Clinicians in China: A Cross-Sectional Survey

Background: Metformin extended-release (XR) is a once-daily alternative conventional immediate-release (IR) tablet for adults with type 2 diabetes.

Aim: This study aimed to investigate the knowledge, attitude, and practice of the use of metformin XR tablets among clinicians.

Methods: We conducted a cross-sectional online survey among endocrinologists, general practitioners, and internists, who are taking routine care of adults with type 2 diabetes in health institutes at all levels in Sichuan Province, China. We designed an online questionnaire including the demographic information, knowledge, attitude, and practice about metformin XR tablets.

Results: We included 158 clinicians, 67.7% of whom were females and 63.9% were from tertiary hospitals. The median age was 39.6 years (ranging between 22 and 62 years). Only 8.2% of the clinicians correctly answered the knowledge questions, 82.3% and 62.0% of the responders assumed that metformin XR had superior efficacy and tolerability to the metformin IR, respectively. Only 46.8% of the clinicians prescribed the metformin XR based on the patient’s preference for once daily frequency.

Conclusion: The knowledge, attitude, and practice of metformin XR among Chinese clinicians need improving. Clinicians need credible information to support their clinical decision-making regarding metformin XR.

Efficacy and Side Effect Profile of Different Formulations of Metformin: A Systematic Review and Meta-Analysis

INTRODUCTION

Metformin is among the most frequently prescribed drugs worldwide for a variety of indications. Although metformin has several important advantages, for example being easy to store and administer, it is associated with a high incidence of gastrointestinal side effects. Slower-release formulations of metformin may reduce the incidence of side effects while maintaining efficacy; however, there is a lack of systematic evidence available to guide head-to-head comparisons between different metformin formulations.

METHODS

PubMed, Web of Science, OVID EMBASE, MEDLINE, The Cochrane database and Clinicaltrials.gov were systematically searched (from inception to 25 January 2021). Trials that randomized adult participants to extended-release formulation of metformin (met-XR), delayed-release (met-DR) or immediate-release metformin (met-IR) were included. Two reviewers independently assessed articles for eligibility and risk-of-bias, with conflicts resolved by a third reviewer. Outcome measures were change in fasting plasma glucose (FPG), glycated haemoglobin (HbA1c), body weight, BMI, lipid profile and side effects. Meta-analyses were conducted using random-effects models.

RESULTS

Fifteen studies (n = 3765) met eligibility criteria. There was no significant difference between the efficacy of met-IR, met-XR or met-DR in changing FPG (p = 0.93). A non-significant reduction in mean body weight was observed in individuals randomized to met-XR vs. met-IR (- 1.03 kg, 95% CI - 2.12 to 0.05, p = 0.06). Individuals randomized to met-XR vs. met-IR had lower low-density lipoprotein (LDL) cholesterol levels (- 5.73 mg/dl, 95% CI - 7.91 to - 3.56, p < 0.00001). Gastrointestinal (GI) side effects were markedly reduced in patients randomised to met-DR vs. met-IR (OR 0.45, 95% CI 0.26-0.80, p = 0.006).

CONCLUSION

Our results demonstrate equal efficacy of longer-acting formulations (met-XR, met-DR) versus immediate-release metformin formulations in terms of glycaemic control. There were insufficient studies available to compare the efficacy of different metformin formulations outside of diabetes care. However met-XR was associated with reduced serum LDL cholesterol concentrations, while met-DR was strongly associated with reduced GI side effects, which could improve drug compliance.

Long-Acting Metformin Vs. Metformin Immediate Release in Patients With Type 2 Diabetes: A Systematic Review

Background: Metformin, a commonly used antidiabetic medication, is available in both an immediate-release (IR) formulation and a long-acting formulation (metformin extended-release; XR). Objective: We performed a systematic review to compare the effectiveness, safety, and patient compliance and satisfaction between the metformin IR and XR formulations. Method: We searched for randomized control trials (RCTs) and observational studies comparing the effectiveness, safety, or patient compliance and satisfaction of metformin XR with metformin IR using the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. Following report screening, data collection, and risk of bias assessment, we separately pooled data from RCTs and observational studies using the Grading of Recommendation Assessment, Development, and Evaluation approach to rate the quality of evidence. Result: We included five RCTs, comprising a total of 1,662 patients, and one observational study, comprising 10,909 patients. In the meta-analyses, no differences were identified in outcomes of effectiveness and safety between the two forms of metformin (including change in HbA1c: mean difference (MD), 0.04%, 95% confidence interval [CI], -0.05-0.13%, fasting blood glucose: MD, -0.03 mmol/L, 95% CI, -0.22-0.15 mmol/L, postprandial blood glucose: MD, 0.50 mmol/L, 95% CI, -0.71-1.72 mmol/L, adverse events of abdominal pain: relative risk (RR), 1.15, 95% CI, 0.57-2.33, all-cause death (RR, 3.02, 95% CI 0.12-73.85), any adverse events (RR, 1.14, 95% CI 0.97-1.34), any adverse events leading to treatment discontinuation: RR, 1.51, 95% CI, 0.82-2.8, any gastrointestinal adverse events: RR, 1.09, 95% CI, 0.93-1.29, diarrhea: RR, 0.82, 95% CI, 0.53-1.27, flatulence: RR, 0.43, 95% CI, 0.15-1.23, nausea: RR, 0.97, 95% CI, 0.64-1.47, severe adverse events: RR, 0.64, 95% CI, 0.28-1.42, and vomiting: RR, 1.46, 95% CI, 0.6-3.56). Data from both the RCTs and the observational study indicate mildly superior patient compliance with metformin XR use compared with metformin IR use; this result was attributable to the preference for once-daily administration with metformin XR. Conclusion: Our systematic review indicates that metformin XR and IR formulations have similar effectiveness and safety, but that metformin XR is associated with improved compliance to treatment.

Metformin treatment and gastrointestinal symptoms in youth: Findings from a large tertiary care referral center

OBJECTIVES

Metformin is the only oral therapy for youth with type 2 diabetes, but up to 50% require additional agents within 2 years of diagnosis. Extended-release (XR) metformin formulations may improve adherence and tolerability-important mediators of treatment response-but data in youth is lacking. To evaluate rates of gastrointestinal (GI) symptoms in patients treated with metformin (SR and XR) and the change in GI symptoms after changes in metformin therapy.

RESEARCH DESIGN AND METHODS

Retrospective chart review of youth with Type 2 or prediabetes seen in a multidisciplinary clinic during 2016-2019.

RESULTS

Of 488 eligible patients, 41.4% and 21.1% were taking metformin SR and XR respectively, with most (58%, n = 178/305) taking a total daily dose of ≥1500 mg/day. Those not on metformin tended to be younger, leaner, and had lower HbA1cs than those taking metformin, p < 0.05. Thirty percentage of patients described GI symptoms, most commonly, abdominal pain and diarrhea. There was no difference in GI symptoms in those on SR versus XR (18.3% vs. 14.6%, p = 0.41). Among patients who initiated metformin, rates of GI symptoms increased (13%-33%, p = 0.001, n = 99), while rates tended to decrease when metformin was discontinued (28%-12%, p = 0.076, n = 50). Rates of GI symptoms were unchanged among those that switched from SR to XR metformin (17% vs. 14%, p = 0.6, n = 58).

CONCLUSIONS

GI symptoms are common in youth with type 2 diabetes taking metformin XR and SR. Adjuncts to mitigate GI symptoms in youth on metformin therapy are needed to improve quality of life and medication adherence.

In Vitro Dissolution and In Vivo Bioequivalence Evaluation of Two Metformin Extended-Release Tablets

The objective of the present study was to evaluate the bioequivalence between generic and branded metformin extended-release (ER) tablets in Chinese subjects. We tested bioequivalence in vitro and in vivo using a comparative dissolution study and a comparative pharmacokinetic trial. Safety assessments were conducted throughout the entire trial period. The dissolution profiles of the generic formulation expressed obvious extended-release properties, similar to those of the branded formulation (f₂ > 60.0%). Consistent with the result of the in vitro study, no remarkable differences were found in terms of pharmacokinetic profiles between generic and branded formulations. The 90% confidence intervals of Ln AUC_0-36 h , Ln AUC_0-∞ , and Ln C_max from generic formulation versus branded formulation were 91.4% to 105.0%, 91.3% to 104.7%, and 101.2% to 119.4%, respectively. During the entire trial period, 4 subjects experienced 11 adverse events. All these were mild and spontaneously resolved. The results obtained from the present study suggest that the generic and branded metformin ER tablets were bioequivalent in Chinese subjects.

Mouse model of metformin-induced diarrhea

OBJECTIVE

Metformin, an oral medication used for type 2 diabetes mellitus, is the most commonly prescribed drug with less economic burden of patients. Although metformin's efficacy and safety have long been recognized, approximately 5% of the patients treated with this drug develop severe diarrhea as an adverse effect and have to abandon treatment. Because there is no animal model to study metformin-induced diarrhea, it is hard to develop methods to maintain quality of life of patients prescribed with metformin.

RESEARCH DESIGN AND METHODS

Using mouse models, we tried to develop an evaluation system for metformin-induced diarrhea to improve diarrheal symptoms in patients with diabetes. Healthy (C57BL/6J) and diabetic obese (db/db) mice were subjected to a stepwise dose escalation of metformin (250 mg/kg/day (125 mg/kg twice daily oral dose)-1000 mg/kg/day (500 mg/kg twice daily oral dose)), and fecal moisture contents and their score were monitored. To evaluate anti-diarrheal medications, wood creosote (a traditional medicine) was tested. Several groups of enterobacteria in fresh feces were examined by using PCR.

RESULTS

1000 mg/kg/day (four times maximal effective dose) of metformin significantly increased fecal moisture content. Although no symptoms of diarrhea were observed in healthy C57BL/6J mice, the same dose of metformin induced severe diarrhea in diabetic obese db/db mice. A reduction in PCR signals for the Firmicutes group was associated with metformin-induced diarrhea. Wood creosote reduced diarrhea (high water-content) without affecting metformin's efficacy or enterobacterial flora levels.

CONCLUSIONS

We have created the first animal model of metformin-induced diarrhea using db/db mice, which will provide better quality of life for patients suffering from diarrhea caused by metformin.

Comparison of gastrointestinal adverse events with different doses of metformin in the treatment of elderly people with type 2 diabetes

WHAT IS KNOWN AND OBJECTIVE

Gastrointestinal discomfort is the most common adverse event of metformin treatment for type 2 diabetes, especially in elderly patients. The aim of this study was to compare gastrointestinal adverse events resulting from different doses of metformin used for the treatment of elderly people with type 2 diabetes.

METHODS

A total of 361 elderly patients with newly diagnosed diabetes were randomly divided into three groups: metformin 1000 mg/d (N = 120), metformin 1500 mg/d (N = 121) and metformin 2000 mg/d (N = 120). Glycaemic control and gastrointestinal adverse events (abdominal pain, diarrhoea, nausea, vomiting, bloating and anorexia) were assessed and compared among the three groups after 12 weeks of treatment.

RESULTS AND DISCUSSION

At baseline, there was no significant difference in gastrointestinal symptoms among the three groups. After 12 weeks of treatment with metformin, the change in HbA_1c level was -0.7%, -0.9% and -1.0% for the 1000 mg/d, 1500 mg/d and 2000 mg/d groups, respectively (P < .0001). There was no significant difference in gastrointestinal adverse events among the three groups after treatment with metformin. In total, 62 people (17.2%) could not tolerate the adverse effects of metformin, and most of them stopped treatment in the first 4 weeks. Logistic regression analysis shows that female sex (OR = 2.660, 95%CI 1.692-4.183, P < .0001) and the concurrent use of organic cation transporter 1-inhibiting drugs (OR = 1.874, 95%CI 1.076-3.265, P = .027) are independent risk factors for adverse events.

WHAT IS NEW AND CONCLUSIONS

Our data demonstrate that metformin doses of 1000 mg/d-2000 mg/d have similar adverse events but that 2000 mg/d of metformin yields the best glycaemic control in elderly people with diabetes. If elderly people can tolerate 1000 mg/d of metformin, we could gradually increase the dose to 2000 mg/d to achieve better glycaemic control.

Effects of liraglutide, metformin and gliclazide on body composition in patients with both type 2 diabetes and non-alcoholic fatty liver disease: A randomized trial

AIMS/INTRODUCTION

To compare the effects of gliclazide, liraglutide and metformin on body composition in patients with type 2 diabetes mellitus with non-alcoholic fatty liver disease.

MATERIALS AND METHODS

A total of 85 patients were randomly allocated to receive gliclazide (n = 27), liraglutide (n = 29) or metformin (n = 29) monotherapy for 24 weeks. Body composition was measured using dual-energy X-ray absorptiometry.

RESULTS

Liraglutide and metformin reduced total, trunk, limb, android and gynoid fat mass; this also led to weight reduction. However, gliclazide treatment produced no significant changes in weight or fat mass, likely because reductions in fat mass were concomitant with increases in lean tissue mass. Blood glucose concentrations and glycated hemoglobin levels improved in all treatment arms; levels of the latter were lower in patients treated with liraglutide and metformin. Serum alanine aminotransferase concentrations decreased in all treatment arms, whereas serum aspartate aminotransferase concentrations were reduced only by liraglutide and metformin. In all patients, weight loss and total, trunk, limb, and android fat mass reductions were positively correlated with decreases in serum alanine aminotransferase and aspartate aminotransferase levels, whereas reductions in waist circumference were positively correlated with lower serum alanine aminotransferase levels.

CONCLUSIONS

Compared with gliclazide, liraglutide and metformin monotherapies result in greater weight loss, reductions in body fat mass, and better blood glucose control among type 2 diabetes mellitus patients with non-alcoholic fatty liver disease. Reductions in weight, fat mass and waist circumference favorably affect hepatic function.