- Eli Lilly on Wednesday said its experimental diabetes drug tirzepatide succeeded in its first Phase 3 trial, reporting results showing treatment significantly lowered blood sugar levels in study participants.
- More than one in five people given a high dose of the drug, however, quit treatment in the trial, called SURPASS-1. Lilly said the majority of discontinuations "were due to reasons other than adverse events," rather than the nausea and vomiting that frequently happens with drugs like tirzepatide.
- Lilly needs tirzepatide to strengthen its diabetes drug business, led by the top-selling once-weekly shot Trulicity, which is under pressure from Novo Nordisk's competing drugs Ozempic and Rybelsus. Novo's tirzepatide rival is still in early development, as the Danish company has put more focus on developing a once-weekly insulin.
Lilly set a high bar in 2014 when it launched Trulicity, the first once-weekly drug in a class called GLP-1 agonists, and began taking market share from Novo's daily injection Victoza. Novo responded three years later with Ozempic, and then upped the stakes when it won approval for an oral version called Rybelsus in 2019.
Sales of Trulicity earned Lilly $3.2 billion in 2019, accounting for around one-quarter of the company's revenue.
Tirzepatide is part of the next wave of diabetes drug research, which is targeting two pathways aimed at stimulating the body's secretion of blood sugar-lowering insulin. The SURPASS-1 trial set out to prove the shot was better than a placebo in lowering blood sugar, and succeeded on that measure.
Patients enrolled in the trial had an average blood sugar level of 7.9% at baseline, above the normal level of 5.7% or less. A once-weekly 15 milligram dose of tirzepatide reduced that number by more than 2 percentage points on average, to about 5.8% at 40 weeks.
Patients taking placebo in SURPASS-1 had their blood sugar levels rise slightly.
Once-weekly Trulicity at a 1.5 mg dose, by comparison, lowered blood sugar by an average of 0.8 percentage points after 26 weeks of treatment.
Lilly said about half of people on the 15 mg dose of tirzepatide in SURPASS-1 achieved a normal blood sugar level.
The main side effects of concern for GLP-1 drugs are gastrointestinal, and tirzepatide was no different. At the 15 mg dose, 18% reported nausea and 6% vomiting. More than 21% of participants on the 15 mg dose dropped out of the trial, but Lilly said "concerns due to the coronavirus pandemic and family or work reasons" were the leading explanations, not the drug's side effects.
Those discontinuations were not part of the efficacy analysis Lilly presented, however, an omission that Cowen analyst Steve Scala said "muddied" the company's interpretation of the data.
Still, Cantor Fitzgerald analyst Louise Chen wrote that the SURPASS-1 data bode well for other trials in Lilly's pivotal program for tirzepatide, including a head-to-head test against Ozempic. All of those studies are expected to read out data in the first half of 2021.
Vamil Divan, an analyst at Mizuho Securities USA, said the data should reassure investors "to remain comfortable with Lilly's outlook even beyond Trulicity's loss of exclusivity," which is due in 2027.
Lilly shares rose 5% in early trading today, changing hands at about $156 apiece.