Evaluation of dirlotapide for sustained weight loss in overweight Labrador retrievers

Advances in Drug Treatments for Companion Animal Obesity

Companion animal obesity has emerged as a significant veterinary health concern globally, with escalating rates posing challenges for preventive and therapeutic interventions. Obesity not only leads to immediate health problems but also contributes to various comorbidities affecting animal well-being and longevity, with consequent emotional and financial burdens on owners. While past treatment strategies have shown limited success, recent breakthroughs in human medicine present new opportunities for addressing this complex issue in companion animals. Here, we discuss the potential of GLP-1 receptor agonists, specifically semaglutide and tirzepatide, already approved for human use, for addressing companion animal obesity. These drugs, originally developed to treat type 2 diabetes in humans and subsequently repurposed to treat obesity, have demonstrated remarkable weight loss effects in rodents, non-human primates and people. Additionally, newer drug combinations have shown even more promising results in clinical trials. Despite current cost and supply challenges, advancements in oral and/or extended-release formulations and increased production may make these drugs more accessible for veterinary use. Thus, these drugs may have utility in companion animal weight management, and future feasibility studies exploring their efficacy and safety in treating companion animal obesity are warranted.

Weight management in obese pets: the tailoring concept and how it can improve results

Obesity is now recognised as the most important medical disease in pets worldwide. All current strategies for weight management involve dietary energy restriction with a purpose-formulated diet. Whilst current weight management regimes can be successful, outcomes are often disappointing with the rate of weight loss progressively slowing down as time goes on. Success is most challenging for the most obese dogs and cats that are more likely to discontinue the programme before reaching target weight. To improve outcomes, clinicians must focus carefully on better tailoring programmes, paying particular to setting an appropriate target weight so as to maximise the benefits for the individual. In this opinionated review, the author will discuss findings from recent clinical research studies examining weight management in obese dogs and cats. A strategy for tailoring weight management targets will then be discussed, illustrated with case examples.

Outcomes of weight management in obese pet dogs: what can we do better?

Obesity is arguably the biggest health and welfare issue affecting pet dogs. Although successful weight loss has health benefits, current strategies are far from ideal. Many obese dogs that start a weight programme fail to lose weight, or subsequently regain the weight they have lost. Given that current weight loss strategies are not perfect, clinicians need to focus carefully on tailoring the programme, perhaps setting a pragmatic target for weight loss, so as to ensure the benefits are maximised. This review will summarise key findings from recent clinical research into pet obesity, and present a framework for improving success, by better tailoring weight management regimens and end points to the individual.

Cohort Study of the Success of Controlled Weight Loss Programs for Obese Dogs

BACKGROUND

Most weight loss studies in obese dogs assess rate and percentage of weight loss in the first 2-3 months, rather than the likelihood of successfully reaching target weight.

OBJECTIVE

To determine outcome of controlled weight loss programs for obese dogs, and to determine the factors associated with successful completion.

ANIMALS

143 obese dogs undergoing a controlled weight loss program.

METHODS

This was a cohort study of obese dogs attending a referral weight management clinic. Dogs were studied during their period of weight loss, and cases classified according to outcome as "completed" (reached target weight), "euthanized" (was euthanized before reaching target weight), or "stopped prematurely" (program stopped early for other reasons). Factors associated with successful completion were assessed using simple and multiple logistic regression.

RESULTS

87/143 dogs (61%) completed their weight loss program, 11 [8%] died or were euthanized, and the remaining 45 [32%] stopped prematurely. Reasons for dogs stopping prematurely included inability to contact owner, refusal to comply with weight management advice, or development of another illness. Successful weight loss was positively associated with a faster rate (P < .001), a longer duration (P < .001), and feeding a dried weight management diet (P = .010), but negatively associated with starting body fat (P < .001), and use of dirlotapide (P = .0046).

CONCLUSIONS AND CLINICAL RELEVANCE

Just over half of all obese dogs on a controlled weight loss program reach their target weight. Future studies should better clarify reasons for success in individual cases, and also the role of factors such as activity and behavioral modification.

2014 AAHA weight management guidelines for dogs and cats

Communicating and implementing a weight management program for dogs and cats can be a challenging endeavor for veterinarians, but a rewarding one. An effective individualized weight loss program provides a consistent and healthy rate of weight loss to reduce risk of disease, prevent malnutrition, and improve quality of life. Weight loss is achieved with appropriate caloric restriction, diet selection, exercise, and strategies to help modify behavior of both the pet and client. This document offers guidelines and tools for the management of weight loss and long-term maintenance of healthy weight.

Effects of low-fat high-fibre diet and mitratapide on body weight reduction, blood pressure and metabolic parameters in obese dogs

The aim of the present study was to compare the impact on blood pressure and different metabolic parameters of a weight-loss program on obese dogs fed on a low-fat high-fibre diet and treated with and without mitratapide. The study sample consisted of 36 obese dogs, randomly assigned to a control group (n=17), which were fed on a low-fat high-fibre diet, and an intervention group (n=19), fed on the same diet and treated with mitratapide. Variables measured included body condition score, body weight, heart rate, systolic and diastolic blood pressures; total cholesterol, triglycerides and glucose levels; alanine aminotransferase and alkaline phosphatase activity, measured both at baseline (day 0) and at the end of the weight loss program (day 85). All the studied parameters had decreased in both groups at the end of the study; these being diastolic blood pressure, total cholesterol and alanine aminotransferase, significantly lower in dogs treated with mitratapide. The use of mitrapide in addition to low-fat high-fibre diet does not seem to offer any further useful effect in the loss of weight during the treatment of canine obesity. On the other hand, mitratapide seems to present certain beneficial effects on pathologies associated with obesity, these being mainly related to blood pressure, lipids and hepatic parameters.

Low-maintenance energy requirements of obese dogs after weight loss

Weight rebound after successful weight loss is a well-known phenomenon in humans and dogs, possibly due to the fact that energy restriction improves metabolic efficiency, reducing post-weight-loss maintenance energy requirements (MER). The aim of the present study was to estimate post-weight-loss MER in obese pet dogs that had successfully lost weight and did not subsequently rebound. A total of twenty-four obese dogs, successfully completing a weight management programme at the Royal Canin Weight Management Clinic, University of Liverpool (Wirral, UK), were included. In all dogs, a period of >14 d of stable weight ( < 1 % change) was identified post-weight loss, when food intake was constant and activity levels were stable (assessed via owners' diary records). Post-weight-loss MER was indirectly estimated by determining dietary energy consumption during this stable weight period. Multivariable linear regression was used to identify factors that were associated with post-weight-loss MER. The mean length of stable weight after weight loss was 54 (SD 34.1) d. During this time, MER was 285 (SD 54.8) kJ/kg(0.75) per d. The rate of prior weight loss and food intake during the weight-loss phase was positively associated with post-weight-loss MER, while the amount of lean tissue lost was negatively associated with post-weight-loss MER. MER are low after weight loss in obese pet dogs (typically only 10 % more than required during weight-loss MER), which has implications for what should constitute the optimal diet during this period. Preserving lean tissue during weight loss may maximise post-weight-loss MER and help prevent rebound.

Long-term follow-up after weight management in obese dogs: the role of diet in preventing regain

Regain after weight loss is widely reported in humans, but there is little information on this phenomenon in dogs. The current study aim was to determine long-term success of a weight loss regime and those factors linked with regain. Thirty-three obese dogs, that had successfully lost weight, were included, all enrolled between December 2004 and May 2009. After weight loss, dogs were switched to a maintenance regime and follow-up weight checks were performed periodically. A review of cases that had completed their weight programme was held during the summer of 2010 and a follow-up check was subsequently conducted, where dogs were reweighed and information was collected on current feeding practices. Median duration of follow-up was 640 days (119-1828 days). Fourteen dogs (42%) maintained weight, 3 (9%) lost >5% additional weight, and 16 (48%) gained >5% weight. Dogs fed a purpose-formulated weight loss diet regained less weight than those switched onto a standard maintenance diet (P=0.0016). Energy intake at the time of follow-up was significantly higher in those dogs fed a standard maintenance diet, compared with those that had remained on a purpose-formulated weight loss diet (P=0.017). These results suggest that weight regain occurs in about half of dogs after successful weight loss. Long-term use of a purpose-formulated weight management diet can significantly limit regain in the follow-up period, likely by limiting food intake.

Dirlotapide: a review of its properties and role in the management of obesity in dogs

Dirlotapide is a microsomal triglyceride transfer protein (MTP) inhibitor developed specifically for canine weight reduction. MTP catalyzes the assembly of triglyceride-rich apolipoprotein-B containing lipoproteins to form chylomicrons in the intestinal mucosa and very low-density lipoproteins in the liver. Following oral administration, dirlotapide has in vivo selectivity for intestinal MTP compared with hepatic MTP. In addition to reducing intestinal fat absorption, dirlotapide also reduces food intake in a dose-dependent manner, probably via increased release of peptide YY into the circulation. The decrease in food intake is responsible for the majority of the weight reduction effect. In clinical use, it is recommended to adjust the dose according to the observed weight loss of each individual. The initial dose of 0.05 mg/kg is doubled after 14 days and then adjusted monthly, the maximum permitted daily dose is 1.0 mg/kg, although doses as high as 10 mg/kg have been administered to dogs without severe adverse experience in safety studies. Dirlotapide can be used without necessitating changes to the current feeding or exercise regimens, but it is desirable to monitor the food intake during weight-stabilization to establish revised feeding and exercise routines that will minimize the risk of weight regain post-treatment. The drug offers a novel approach that is applicable in cases where dietary management alone has proved to be unsuccessful.

Efficacy and safety of dirlotapide in the management of obese dogs evaluated in two placebo-controlled, masked clinical studies in North America

Dirlotapide was evaluated in the management of obesity in dogs in two multicenter, clinical studies in North America. A total of 335 obese dogs of various breeds were randomized to dirlotapide or placebo in a 2:1 ratio. Dirlotapide was administered orally once daily to dogs at an initial dose of 0.05 mg/kg, increased after 14 days to 0.1 (study B, label dose) or 0.2 mg/kg (study A) and then adjusted according to individual weight loss at 28-day intervals. Dogs were examined and weighed, and body condition scores (BCSs) were recorded every 28 days. Study A had three consecutive phases: weight loss (16 weeks, day 0-112); weight management (12 weeks); and post-treatment (8 weeks). Study B had a weight loss phase only. For dirlotapide-treated dogs, mean weight loss by day 112 was 11.8-14.0% compared with 3.0-3.9% for placebo (P = 0.0001). In study A, weight losses for dirlotapide were 19.3% after 12 weeks of weight management and 16.7% (regain of 3.4%) by 8 weeks after dirlotapide was discontinued. In both studies, dogs in both treatments had emesis, lethargy, anorexia, diarrhea, and mildly elevated hepatic transaminase activity, that resolved spontaneously with time. These were experienced more frequently with dirlotapide. Improved activity levels and BCS for >50% dogs were reported with dirlotapide. Dirlotapide was safe and effective in the reduction and management of body weight in obese dogs.

Biologic activity of dirlotapide, a novel microsomal triglyceride transfer protein inhibitor, for weight loss in obese dogs

Dirlotapide is a novel microsomal triglyceride transfer protein inhibitor intended for the treatment and management of obesity in dogs. The biologic effects of dirlotapide, weight loss, decreased food intake, increased fecal fat, decreased serum cholesterol, and body composition, were evaluated in a controlled, blinded study. Sixteen obese beagles were randomized to treatment with placebo (n = 4) or dirlotapide (n = 12) following a 2-week acclimation period in which baseline data were collected. The dirlotapide dose, adjusted to produce weight loss for 3 months and then stabilize body weight for 1 month (weight management), produced a significant difference (expressed as a percentage of baselines) in weekly weight loss, food intake, fecal fat, serum cholesterol concentration, and body composition (measured by dual energy X-ray absorptiometry) compared with placebo treatment (P < 0.05). The initial dirlotapide dosage of 0.5 mg/kg (10 times the initial label dose) resulted in a high rate of weight loss (3.3% weekly) and anorexia, emesis, and loose stools for some dogs. A 25% dose reduction (mean dosage: 0.36 mg/kg) followed by biweekly 25% dose adjustments based on individual weight loss, produced 1-2% weekly weight loss and total weight loss of 18.8% in 12 weeks at a final mean dosage of 0.41 mg/kg (range: 0.15-0.60); a dosage range of 0.10-0.34 mg/kg stabilized body weight. Body weight changes for placebo-treated dogs were -0.8% to +0.9% weekly; total weight gain during the weight loss phase was 10.6%. No apparent change in food intake, percentage of fecal fat, and serum cholesterol was observed in the placebo group. Food intake and body weight increased when dirlotapide was discontinued. Dirlotapide produced weight loss by both reducing appetite (about 90% of the weight loss activity) and by increasing fecal fat excretion (about 10% of the weight loss activity).

An evaluation of dirlotapide to reduce body weight of client-owned dogs in two placebo-controlled clinical studies in Europe

The clinical efficacy for weight loss and safety of dirlotapide in dogs were evaluated in two multi-centre studies with parallel designs. Overweight, adult dogs (n = 245) of various breeds were randomized to treatment with dirlotapide or placebo in a 2:1 ratio. Dirlotapide was administered orally once daily to dogs at an initial dose of 0.05 mg/kg/day commencing on day 0 and doubled after 14 days. Every 28 days, dogs were examined, weighed, body condition scores (BCS) were recorded, and dose was adjusted to meet weight loss targets. Each study comprised three consecutive phases: weight-loss (up to day 196); weight-stabilization (84 days); and post-treatment (28 days). pre-treatment feeding and exercise regimens were continued during treatment. Dirlotapide-treated dogs showed mean weight loss of 15.9% (study A) and 14.0% (study B) by the end of weight loss phase (up to day 196). Percentage weekly weight losses for dirlotapide were significantly greater than for placebo (P < or = 0.0002). Emesis and diarrhoea were experienced in both treatments but were more frequent with dirlotapide; resolution was spontaneous. BCS improved for 75.7-82.5% of dogs on dirlotapide treatment compared with 15.4-41.4% for placebo. Mean dirlotapide dosage at end of weight-loss phase was 0.38 (study A) and 0.29 (study B) mg/kg initial body weight/day. Dirlotapide was found to be clinically safe and effective in the reduction of body weight in overweight dogs.

The safety of dirlotapide in dogs

The safety of dirlotapide in dogs was evaluated in two studies with parallel designs. In an acute tolerance study, 24 beagles (six dogs per treatment) were treated orally once daily for 14 days with placebo or dirlotapide at 2.5, 5.0, or 10.0 mg/kg/day. In a margin-of-safety study, 38 overweight, neutered beagles were treated orally once daily for 3 months with dirlotapide at doses up to 0.5 mg/kg/day (six dogs), 1.5 mg/kg/day (12 dogs) and 2.5 mg/kg/day (six dogs). Control dogs received placebo at 0.3 mL/kg/day (10 dogs) and 0.5 mL/kg/day (four dogs). Results were similar for both studies, and no serious adverse events were observed. Dirlotapide was clinically well-tolerated in dogs at dosages up to 10 mg/kg/day for 14 days and 2.5 mg/kg/day for 3 months. Dirlotapide produced the expected decrease in food intake and body weight (up to 20-40%) without ill effects. Clinical, pathologic, and histopathologic findings were reversible and consistent with suppression of food intake and rapid weight loss produced by elevated dirlotapide dosages. In both studies, sporadic emesis and loose stools were observed in both placebo and dirlotapide-treated dogs. Incidence of emesis generally increased with dose and decreased with treatment time. Elevations in hepatic transaminase activity were seen in dogs treated with more than 1.5 mg/kg dirlotapide daily, but were not associated with clinical signs or microscopic evidence of hepatic degeneration or necrosis.

Influence of dirlotapide, a microsomal triglyceride transfer protein inhibitor, on the digestibility of a dry expanded diet in adult dogs

The objectives of this study were to evaluate the effects of dirlotapide, a microsomal triglyceride transfer protein inhibitor, on apparent nutrient digestibility of an expanded dry dog food, on defecation frequency and fecal consistency. Eighteen beagles were randomized to either placebo (n = 6) or dirlotapide (n = 12). Testing was divided into a 21-day adaptation phase (days -21 to -1) and a 35-day treatment (digestibility testing) phase (days 0-35). During the treatment phase, dogs were administered oral dirlotapide (0.3 mg/kg) or placebo (0.06 mL/kg) once daily. For digestibility testing, feces were collected over two periods for 7 days each starting on days -9 and 28. All dogs were fed a commercial adult dog food throughout the study. Food intake was adjusted to maintain body weight during adaptation, followed by pair-feeding placebo dogs the amount of food ingested by the dirlotapide dogs during the treatment period. Dogs in both groups had reduced food intake and lost similar amounts of body weight during treatment. Dogs receiving 0.3 mg dirlotapide/kg once daily had a small but significant (P = 0.018) decrease (6.16 +/- 2.22%, mean +/- SD) in crude fat digestibility compared with the placebo-treated food-restricted dogs, but no difference in crude protein, dry matter, or energy digestibility was observed. Fecal consistency and volume and defecation frequency were similar between groups. Dirlotapide effectively reduced appetite and energy intake without affecting nutrient digestibility, except for a minimal decrease in fat digestibility.