Dose distribution and up-titration patterns of metformin monotherapy in patients with type 2 diabetes

Adaptive Control of Tumor Growth

Cancer treatment optimizations select the most optimum combinations of drugs, sequencing schedules, and appropriate doses that would limit toxicity and yield an improved patient quality of life. However, these optimizations often lack an adequate consideration of cancer's near-infinite potential for evolutionary adaptation to therapeutic interventions. Adapting cancer therapy based on monitored tumor burden and clonal composition is an intuitively sound approach to the treatment of cancer as an inherently complex and adaptive system. The adaptation would be driven by clinical outcome setpoints embodying the aims to thwart therapeutic resistance and maintain a long-term management of the disease or even a cure. However, given the nonlinear, stochastic dynamics of tumor response to therapeutic interventions, adaptive therapeutic strategies may at least need a one-step-ahead prediction of tumor burden to maintain their control over tumor growth dynamics. The article explores the feasibility of adaptive cancer treatment driven by tumor state feedback assuming cell adaptive fitness to be the underlying source of phenotypic plasticity and pathway entropy as a biomarker of tumor growth trajectory. The exploration is undertaken using deterministic and stochastic models of tumor growth dynamics.

Metabolic and Metabolomic Effects of Metformin in Murine Model of Pulmonary Adenoma Formation

Epidemiologic studies of diabetic patients treated with metformin identified significantly lower incidences of cancer. From this, there is growing interest in the use of metformin to treat and prevent cancer. Studies have investigated chemopreventive mechanisms including alterations in calorie intake, cancer metabolism, and cell signaling. Repurposing the drug is challenging due to its metabolic effects and non-uniform effects on different types of cancer. In our previously published studies, we observed that benzo[a]pyrene treated mice receiving metformin significantly reduced lung adenomas; however, mice had reduced weight gain. In this study, we compared chemoprevention diets with and without metformin to evaluate the effects of diet vs. effects of metformin. We also performed tandem mass spectrometry on mouse serum to assess metabolomic alterations associated with metformin treatment. In metformin cohorts, the rate of weight gain was reduced, but weights did not vary between diets. There was no weight difference between diets without metformin. Interestingly, caloric intake was increased in metformin treated mice. Metabolomic analysis revealed metabolite alterations consistent with metformin treatment. Based on these results, we conclude that previous reductions in lung adenomas may have been occurred from anticancer effects of metformin rather than a potentially toxic effect such as calorie restriction.

Examining the relationship between metformin dose and cancer survival: A SEER-Medicare analysis

Cancer is a major health problem in the U.S and type 2 diabetes mellitus (T2DM) is known to increase the risk for the development of many cancers. Metformin, a first-line therapy for treating T2DM, is increasingly being used for its anticancer effects; however, the literature is limited on the effect of metformin dose on overall survival in patients with stage IV cancer. Overall survival was defined as the time interval from the date of diagnosis to the last known follow-up or death from any cause. Subjects who were alive on December 31, 2016 were censored. In this cohort study we examined the relationship between metformin dose and overall survival in persons with both T2DM and stage IV lung, breast, colorectal, prostate, or pancreas cancers. We used a retrospective study design with Cox proportional hazards regression analysis of the 2007–2016 of the Surveillance Epidemiology and End Results-Medicare (SEER) dataset. Of the 7,725 patients, 2,981(38.5%) had been prescribed metformin. Patients who used metformin had significantly better overall survival in both unadjusted (Unadjusted HR, 0.73; 95% CI, 0.69–0.76; p < 0.001) and adjusted models (adjusted HR, 0.77; 95% CI, 0.73–0.81; p < 0.001). The overall survival between patients who took metformin with average daily dose ≥ 1000mg or < 1000mg were not statistically significant (aHR, 1.00; 95% CI, 0.93–1.08; p = 0.90). Metformin use regardless of dose is associated with increased overall survival in older adults with stage IV cancer.

Real-World Clinical Experience on the Usage of High-Dose Metformin (1500-2500 mg/day) in Type 2 Diabetes Management

Background:

To evaluate the clinical characteristics, treatment patterns, and clinical effectiveness and safety of high doses of metformin (1500-2500 mg/day) in Indian adults with type 2 diabetes mellitus (T2DM).

Materials and methods:

A retrospective, multicentric (n = 241), real-world study included patients with T2DM (aged >18 years) receiving high doses of metformin. Details were retrieved from patient’s medical records.

Results:

Out of 5695 patients, 62.7% were men with median age was 50.0 years. Hypertension (67.5%) and dyslipidemia (48.7%) were the prevalent comorbidities. Doses of 2000 mg (57.4%) and 1500 mg (29.1%) were the most commonly used doses of metformin and median duration of high-dose metformin therapy was 24.0 months. Metformin twice daily was the most frequently used dosage pattern (94.2%). Up-titration of doses was done in 96.8% of patients. The mean HbA1c levels were significantly decreased post-treatment (mean change: 1.08%; P < .001). The target glycemic control was achieved in 91.2% patients. A total of 83.0% had decreased weight. Adverse events were reported in 156 patients. Physician global evaluation of efficacy and tolerability showed majority of patients on a good to excellent scale (98.2% and 97.7%).

Conclusion:

Clinical effectiveness and safety of a high-dose metformin was demonstrated through significant improvement in HbA1c levels and weight reduction.

Metformin dosage patterns in type 2 diabetes patients in a real-world setting in the United States

AIM

To examine metformin dosage patterns among adults with type 2 diabetes in an integrated healthcare system in the US.

METHODS

Using electronic medical records, the proportions of patients receiving different initial metformin doses were reported. Proportion of patients receiving ≥1500 mg metformin daily at initiation or within six months after initiation and the associated sociodemographic and clincal factors were examined.

RESULTS

The cohort included 715 patients (52.6% female, 64.1% white, and mean age = 57.0 ± 12.7 years). Of these, 31.3% received an initial daily metformin dose of <850 mg, 46.9% received 850-1499 mg, and 21.8% received ≥1500 mg and 244 (34.1%) patients received ≥1500 mg metformin daily at initiation or within six months after initiation. Patients aged 65-79 years (vs. those aged <50 years) and blacks (vs. whites) were less likely and Hispanics (vs. whites) and patients with higher HbA1c before metformin initiation were more likely to receive ≥1500 mg metformin daily at initiation or within six months after initiation.

CONCLUSIONS

Study findings suggest a need for efforts to maximize the proportion of eligible patients receiving a recommended metformin dose. Factors impacting metformin dosage identified in the study could be a useful guidance.

The effect of metformin in EML4-ALK+ lung cancer alone and in combination with crizotinib in cell and rodent models

Cell based studies have suggested that the diabetes drug metformin may combine with the anaplastic lymphoma kinase receptor (ALK) inhibitor crizotinib to increase ALK positive lung cancer cell killing and overcome crizotinib resistance. We therefore tested metformin alone and in combination with crizotinib in vivo, by employing a xenograft mouse model of ALK positive lung cancer. We found that 14 days of daily oral metformin (100 mg/kg) alone had a moderate but statistically significant effect on tumour growth suppression, but in combination with crizotinib, produced no greater tumour suppression than crizotinib (25 mg/kg) alone. We also reassessed the effect of metformin on EML₄-ALK positive lung cancer (H3122) cell viability. Although metformin alone did have a moderate effect on cell viability (30% suppression) this was only at a clinically irrelevant concentration (5 mM) and there was no additive effect with cytotoxic concentrations of crizotinib. Moreover, metformin did not overcome crizotinib resistance in our resistant cells. Nevertheless, we were able to show that metformin induces a G1-cell cycle arrest and apoptosis alone and in combination with crizotinib. Also, consistent with earlier work, the addition of insulin-like growth factor-1 (IGF-1) to EML₄-ALK positive cancer cells reduced cell killing by crizotinib. We therefore hypothesised that the effect of metformin in vivo was not due to direct cytotoxicity on cancer cells, but by modulation of IGF-1 expression. We therefore measured levels of IGF-1 in plasma taken from mice treated with metformin, but found no difference between the drug treatment and control groups. We further hypothesised that the effect of metformin could be due to modulation of thrombospondin 1 (TSP-1), which metformin has been proposed to regulatein vivo, but again we found no difference between the experimental groups. Finally, we investigated the potential for liver and kidney toxicity, as well as CYP3A based interactions, from the combination of metformin with crizotinib.