Jonathan Hauptman

Role of Orlistat in the Treatment of Obese Patients With Type 2 Diabetes: A 1-year randomized double-blind study

OBJECTIVE Obesity is an important risk factor for type 2 diabetes. Weight loss in patients with type 2 diabetes is associated with improved glycemic control and reduced cardiovascular disease risk factors, but weight loss is notably difficult to achieve and sustain with caloric restriction and exercise. The purpose of this study was to assess the impact of treatment with orlistat, a pancreatic lipase inhibitor, on weight loss, glycemic control, and serum lipid levels in obese patients with type 2 diabetes on sulfonylurea medications. RESEARCH DESIGN AND METHODS In a multicenter 57-week randomized double-blind placebo-controlled study, 120 mg orlistat or placebo was administered orally three times a day with a mildly hypocaloric diet to 391 obese men and women with type 2 diabetes who were aged > 18 years, had a BMI of 28–40 kg/m2, and were clinically stable on oral sulfonylureas. Changes in body weight, glycemic control, lipid levels, and drug tolerability were measured. RESULTS After 1 year of treatment, the orlistat group lost 6.2 ± 0.45% (mean ± SEM) of initial body weight vs. 4.3 ± 0.49% in the placebo group (P < 0.001). Twice as many patients receiving orlistat (49 vs. 23%) lost ≥ 5% of initial body weight (P < 0.001). Orlistat treatment plus diet compared with placebo plus diet was associated with significant improvement in glycemic control, as reflected in decreases in HbA1c (P < 0.001) and fasting plasma glucose (P < 0.001) and in dosage reductions of oral sulfonylurea medication (P < 0.01). Orlistat therapy also resulted in significantly greater improvements than placebo in several lipid parameters, namely, greater reductions in total cholesterol, (P < 0.001), LDL cholesterol (P < 0.001), triglycerides (P < 0.05), apolipoprotein B (P < 0.001), and the LDL-to-HDL cholesterol ratio (P < 0.001). Mild to moderate and transient gastrointestinal events were reported with orlistat therapy, although their association with study withdrawal was low. Fat-soluble vitamin levels generally remained within the reference range, and vitamin supplementation was required in only a few patients. CONCLUSIONS Orlistat is an effective treatment modality in obese patients with type 2 diabetes with respect to clinically meaningful weight loss and maintenance of weight loss, improved glycemic control, and improved lipid profile.

Unimolecular Dual Incretins Maximize Metabolic Benefits in Rodents, Monkeys, and Humans

Compared to best-in-class GLP-1 mono-agonists, unimolecular co-agonists of GLP-1 and GIP with optimized pharmacokinetics enhance glycemic and metabolic benefits in mammals. “Twincretins”: Two Is Better than One Despite obesity-linked diabetes approaching worldwide epidemic proportions and the growing recognition of it as a global health challenge, safe and effective medicines have remained largely elusive. Pharmacological options targeting multiple obesity and diabetes signaling pathways offer greater therapeutic potential compared to molecules targeting a single pathway. Finan et al. now report the discovery, characterization, and translational efficacy of a single molecule that acts equally on the receptors for the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). In rodent models of obesity and diabetes, this dual incretin co-agonist more effectively lowered body fat and corrected hyperglycemia than selective mono-agonists for the GLP-1 and GIP receptors. An enhanced insulinotropic effect translated from rodents to monkeys and humans, with substantially improved levels of glycosylated hemoglobin A1c (HbA1c) in humans with type 2 diabetes. The dual incretin was engineered with selective chemical modifications to enhance pharmacokinetics. This, in combination with its inherent mixed agonism, lowered the drug dose and ameliorated the dose-limiting nausea that has plagued selective GLP-1 therapies. These dual incretin co-agonists signify a new direction for unimolecular combination therapy and represent a new class of drug candidates for the treatment of metabolic diseases. We report the discovery and translational therapeutic efficacy of a peptide with potent, balanced co-agonism at both of the receptors for the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). This unimolecular dual incretin is derived from an intermixed sequence of GLP-1 and GIP, and demonstrated enhanced antihyperglycemic and insulinotropic efficacy relative to selective GLP-1 agonists. Notably, this superior efficacy translated across rodent models of obesity and diabetes, including db/db mice and ZDF rats, to primates (cynomolgus monkeys and humans). Furthermore, this co-agonist exhibited synergism in reducing fat mass in obese rodents, whereas a selective GIP agonist demonstrated negligible weight-lowering efficacy. The unimolecular dual incretins corrected two causal mechanisms of diabesity, adiposity-induced insulin resistance and pancreatic insulin deficiency, more effectively than did selective mono-agonists. The duration of action of the unimolecular dual incretins was refined through site-specific lipidation or PEGylation to support less frequent administration. These peptides provide comparable pharmacology to the native peptides and enhanced efficacy relative to similarly modified selective GLP-1 agonists. The pharmacokinetic enhancement lessened peak drug exposure and, in combination with less dependence on GLP-1–mediated pharmacology, avoided the adverse gastrointestinal effects that typify selective GLP-1–based agonists. This discovery and validation of a balanced and high-potency dual incretin agonist enables a more physiological approach to management of diseases associated with impaired glucose tolerance.

Initial studies in humans with the novel gastrointestinal lipase inhibitor Ro 18–0647 (tetrahydrolipstatin)

Excessive intake of dietary fat contributes to the development and maintenance of both obesity and hyperlipidemia. Inhibition of gastrointestinal lipases could decrease the amount of ingested fat that is absorbed systemically by preventing the hydrolysis of triglycerides. Ro 18-0647, a chemically synthesized derivative of the natural product lipstatin, inhibits the action of gastrointestinal lipases. Initial studies in humans have shown that Ro 18-0647 can reliably increase fecal fat excretion. Ro 18-0647 has also been shown to be well tolerated in the majority of normal volunteers and obese patients studied. Further research must be conducted to determine whether clinical endpoints of weight loss or cholesterol lowering can be produced by using this new pharmacologic principle.

Effect of orlistat-assisted weight loss in decreasing coronary heart disease risk in patients with syndrome X☆

This study describes the changes in risk factors for coronary heart disease in obese persons with syndrome X after orlistat-assisted weight loss. Data were available for 1,700 patients who completed 52 weeks of weight loss; 128 were defined as having syndrome X by being in the quintile with the highest plasma triglyceride levels (>2.2 mM/L) and the lowest high-density lipoprotein cholesterol (HDL, <1.0 mM/L) concentrations. Initial characteristics of those with syndrome X were similar to the 119 subjects (non-syndrome X) in the lowest quintile of plasma triglyceride (<0.975 mM/L) and highest quintile of HDL cholesterol (>1.5 mM/L). Subjects were placed on a calorie-restricted diet, and randomized to receive orlistat or placebo. Initial values were higher in those with syndrome X for diastolic blood pressure (p = 0.03), plasma insulin (p = 0.0001), triglyceride (p = 0.0001) concentrations, and ratio of low-density lipoprotein cholesterol to HDL cholesterol (p = 0.0001), and were lower for HDL cholesterol (p = 0.001) concentrations. Weight loss was greater in both groups of orlistat-treated patients (p = 0.026); in those with syndrome X, it was associated with a significant reduction in plasma insulin (p = 0.019) and triglyceride (p = 0.0001) concentrations, an increase in HDL cholesterol concentration, and a decrease in low-density lipoprotein/HDL cholesterol ratio (p = 0.0001). There were no significant changes in plasma insulin, triglycerides, or HDL cholesterol concentration in the non-syndrome X group. In conclusion, weight loss attenuates coronary heart disease risk factors in obese persons with syndrome X, and the risk factor reduction is enhanced with administration of orlistat.

Long‐Term Systemic Exposure of Orlistat, a Lipase Inhibitor, and Its Metabolites in Obese Patients

Orlistat, a lipase inhibitor, acts locally in the gastrointestinal tract; its systemic exposure is not required for its efficacy. However, knowledge of the extent of its systemic exposure is important for its safe use in obese patients, the intended target population. Pharmacokinetic screening in obese patients was carried out by monitoring plasma concentrations of unchanged orlistat and its metabolites in five key double‐blind, placebo‐controlled phase II/III studies. Results of these studies involving the monitoring of plasma samples indicate that detection of intact orlistat in plasma was sporadic, and measurable concentrations were low (<10 ng/mL or 0.02 μM) without evidence of accumulation, which is consistent with minimal absorption. It is concluded that systemic exposure of orlistat is negligible; at a clinically efficacious dose level, orlistat is unlikely to produce systemic lipase inhibition.

Comment: Low-Dose Orlistat Effects on Body Weight of Mildly to Moderately Overweight Individuals: A 16 Week, Double-Blind, Placebo-Controlled Trial

Background: Lifestyle measures are considered the first line of therapy for treating overweight individuals, but many are unable to achieve a meaningful weight loss. Objective: To determine the efficacy and safety of orlistat 60 mg, given 3 times daily, for weight loss in mildly to moderately overweight individuals. Methods: A multicenter, 16 week, randomized, double-blind, placebo-controlled study was conducted in 391 overweight subjects at 20 US centers. The main outcome measure was change in weight from baseline to week 16; secondary measures included changes in body mass index, waist circumference, blood pressure, and fasting lipoprotein and glucose levels. Results: Subjects in both groups lost weight over the treatment period; however, orlistat-treated subjects lost significantly more weight than placebo-treated subjects beyond 2 weeks of treatment. Weight loss from baseline to week 16 was significantly greater in participants receiving orlistat versus those receiving placebo (3.05 vs 1.90 kg; p < 0.001, intent-to-treat analysis). Orlistat-treated subjects who completed 16 weeks of treatment lost 4.8 ± 0.35% (mean ± SE) of baseline weight compared with 3.1 ± 0.38% for the placebo group (p < 0.001). Orlistat-treated subjects, compared with those receiving placebo, also demonstrated a greater relative reduction in total (–4.4% vs 0.0%; p = 0.004) and low-density lipoprotein cholesterol (–7.2% vs -0.6%; p = 0.005) and both diastolic (-3.9% vs -0.5%; p = 0.001) and systolic blood pressure (-4.7% vs -1.8%; p = 0.004). Both groups showed a similar safety profile; gastrointestinal events were significantly more common in the orlistat-treated subjects. Conclusions: The use of orlistat 60 mg by mildly to moderately overweight individuals produced significant weight loss in conjunction with a reduced calorie diet and self-instructional materials. This amount of weight loss was associated with improvements in several weight-related risk factors. Orlistat 60 mg may be a useful adjunct to lifestyle measures and has the potential to contribute significantly to weight and risk factor improvement for overweight individuals.