On April 28, Eli Lilly announced topline results of tirzepatide from its SURMOUNT-1 Phase III clinical trial. In a groundbreaking effort, participants taking tirzepatide lost up to 52lb (24kg) in this 72-week Phase III study, with 63% of participants taking tirzepatide 15mg achieving at least 20% body weight reductions as a key secondary endpoint. With similar administration and treatment regimens, GlobalData expects that tirzepatide will ultimately outcompete injectable semaglutide in both the type 2 diabetes (T2D) and obesity markets.
Tirzepatide is a novel investigational glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist. It is administered once weekly, subcutaneously. Tirzepatide is primarily indicated for the treatment of T2D and is expected to receive its decision from the FDA in Q2 2022, although no PDUFA date has been set.
Currently obesity is managed through diet, bulking drugs, and appetite suppressors to reduce food consumption and drive weight loss. In June 2021, Novo Nordisk launched and rebranded its T2D treatment and GLP-1 receptor agonist Ozempic (semaglutide) as Wegovy for the treatment of obesity. The launch of Wegovy represented a turning point in the pharmacologic treatment of obesity. The current obesity drugs are not targeted for weight loss and focus on appetite suppression or are label expansions of other marketed drugs. As a result, patients struggled with significant adverse effects and relatively poor efficacy.
Regulatory approval is particularly difficult to obtain for anti-obesity drugs, with little consistency across global regulatory bodies and their approval criteria. The FDA now requires the results of a long-term cardiovascular outcomes trial in the applications. On top of drug development and approval barriers, pharmaceutical companies have largely relied on patient and physician acceptance of out-of-pocket reimbursement. Low rates of insurance reimbursement remain a major barrier, despite clinical guidelines recommending the use of anti-obesity drugs. Medicare in the US excludes coverage of all drugs prescribed for obesity. And, unlike the vast majority of other outpatient pharmaceuticals, weight loss drugs are not a mandatory benefit in the Medicaid program. Private payer coverage of weight loss drugs has been extraordinarily variable.
Like semaglutide, tirzepatide benefits from its position as a T2D treatment in addition to its weight loss benefits, allowing for a greater patient population to be covered, and a greater likelihood of reimbursement. With similar administration and treatment regimens, tirzepatide is poised to compete directly with semaglutide, both on the T2D market and obesity market. In the obesity market, the competitive edge between tirzepatide and semaglutide really will come down to the price of tirzepatide, and its ability to negotiate reimbursement with payers. As a first-in-class therapy in a novel drug class, with demonstrated significant efficacy, it has the potential to be priced at a premium, and GlobalData has assumed it will be priced at a 25% premium to other once-weekly GLP-1 receptor agonists.
Clinical data has clearly demonstrated that tirzepatide has significantly greater efficacy than the currently marketed GLP-1 inhibitors and is effective at tackling patients with T2D and obesity. In a head-to-head study between tirzepatide and semaglutide in patients with T2D, tirzepatide’s estimated mean change from baseline in the level of glycated haemoglobin was greater than semaglutide’s, and the data for reductions in body weight demonstrates that they were greater with tirzepatide. Amongst key opinion leaders (KOLs) interviewed, there has been a keen anticipation for the new class of GLP-1/GIP dual agonists as these are multi-targeted in their approach. These agonists activate both the GLP-1 receptor, as well as the GIP, which alters energy consumption.
Over the next ten years, tirzepatide will likely have gained significant market share and will be part of a new wave of dual and triple agonist therapies in the T2D market. Because tirzepatide demonstrated superiority over semaglutide, it is likely to become the leading injectable in the GLP-1 space, and its success in the T2D market will likely mirror its success in the obesity market, given the current clinical outcomes.