First SGLT1/2 Inhibitor Shows 'Spectacular'
Phase 3 Safety and Efficacy in T2D

Mitchel L. Zoler, PhD

November 18, 2020

Sotagliflozin, a novel type of sodium-glucose cotransporter inhibitor, showed the diverse benefits this drug class provides along with some new twists in a pair of international pivotal trials that together enrolled nearly 12,000 patients with type 2 diabetes.

Unprecedented benefits were seen for the first time with a drug, sotagliflozin (Zynquista) that produces both sodium-glucose cotransporter 2 inhibition as well as SGLT1 inhibition.

They included a big reduction in both MIs and strokes; an ability to meaningfully reduce hyperglycemia in patients with severe renal dysfunction with an estimated glomerular filtration rate (eGFR) of 25-29 mL/min per 1.73 m2; an ability to safely and effectively start in patients still hospitalized (but stable) for an acute heart failure episode; and a striking 37% relative risk reduction in cardiovascular death, heart failure hospitalizations, or an urgent outpatient visit for heart failure in 739 of the patients enrolled in both trials who had heart failure with preserved ejection fraction (HFpEF).

These studies produced for the first time evidence from controlled, prospective, randomized trials that a drug could improve the outcome of HFpEF patients.

All these novel outcomes came on top of the usual benefits clinicians have generally seen across the SGLT2 inhibitors already on the U.S. market: reductions in cardiovascular death and heart failure hospitalizations among all patients with type 2 diabetes, preservation of renal function, and hemoglobin A1c lowering among T2D patients with eGFR levels of at least 30 mL/min per 1.73 m2.

"The data look spectacular," summed up Deepak L. Bhatt, MD, who presented the results from the two trials, SOLOIST-WHF and SCORED, in talks at the virtual scientific sessions of the American Heart Association.

"I think sotagliflozin has the potential to be the best in class" based on the several added attributes shown in the two trials, he said in an interview. "We've shown that it is very safe, well tolerated, and effective."

The primary results were a significant 33% relative risk reduction with sotagliflozin treatment, compared with placebo in the rate of total cardiovascular deaths, hospitalizations for heart failure, or urgent outpatient visits for heart failure during just over 9 months of median follow-up among patients with T2D recently hospitalized for heart failure in SOLOIST-WFH. And a significant 26% relative risk reduction with sotagliflozin for the same endpoint after a median follow-up of just over 14 months in SCORED, which enrolled patients with T2D and chronic kidney disease.

"Sotagliflozin adds to the SGLT2 inhibitor story," and the SOLOIST-WHF results "may shift our focus to vulnerable, acute heart failure patients with an opportunity to treat during the transition phase," when these patients leave the hospital, commented Jane E. Wilcox, MD, the study's designated discussant and a heart failure cardiologist at Northwestern Medicine in Chicago.

A Dual SGLT Inhibitor

What sets sotagliflozin apart from the SGLT2 inhibitors is that it not only inhibits that protein but also SGTL1, which primarily resides in the gastrointestinal tract and is the main route for gut absorption of glucose. Bhatt said that he was unaware of any other SGLT1/2 inhibitors currently in advanced clinical testing.

The activity of sotagliflozin against the SGLT1 protein likely explains its ability to cut A1c levels in patients with severe renal dysfunction, a condition that stymies glucose lowering by SGLT2 inhibitors. In SCORED, which randomized 10,584 patients with T2D at 750 study sites in 44 countries, 813 patients (8%) had an eGFR of 25-29 mL/min per 1.73 m2 at enrollment. Sotagliflozin treatment led to an average 0.6% cut in A1c in this subgroup, and by the same average amount among the patients with GFRs of 30-60 mL/min per 1.73 m2.

"This is a huge finding for endocrinologists and primary care physicians" who treat patients with T2D who have severe renal dysfunction, said Bhatt, a professor of medicine at Harvard Medical School in Boston. "It's a good enough reason by itself to approve this drug."

The same mechanism may also be behind another unexpected finding in SCORED. Treatment with sotagliflozin cut the rate of total episodes of cardiovascular death, nonfatal MI, or nonfatal stroke by an absolute 1.6%, compared with placebo, and by a relative 23%. This benefit was largely driven by a 32% relative risk reduction total in MIs, and a 34% relative risk reduction in total stroke, both significant differences.

"No SGLT2 inhibitor has shown a reduction in stroke, and the MI signals have been mixed. The sizable MI and stroke effects are unique to sotagliflozin," compared with the SGLT2 inhibitors, and likely reflect one or more mechanisms that result from blocked gut SGLT1 and a cut in GI glucose uptake, said Bhatt. "Probably some novel mechanism we don't fully understand."

First-ever HFpEF Benefit

In contrast to these two benefits that are probably unique to drugs that inhibit the SGLT1 protein, sotagliflozin showed two other notable and unprecedented benefits that are likely generalizable to the SGLT2 inhibitors.

First is the striking benefit for HFpEF. Neither SOLOIST, which enrolled 1,222 patients with T2D and just hospitalized for worsening heart failure, nor SCORED, which enrolled patients with T2D and chronic kidney disease based exclusively on an eGFR of 25-60 mL/min per 1.73 m2, excluded patients with HFpEF, defined as heart failure patients with a left ventricular ejection fraction of at least 50%. The two studies together included a total of 739 of these patients, and they split fairly evenly between treatment with sotagliflozin or placebo.

The combined analysis showed that the incidence rate for the primary endpoint in both SOLOIST and SCORED was 59% with placebo and 39% with sotagliflozin, an absolute event reduction of 11.6 events/100 patient-years, and a significant 37% relative risk reduction, with a number needed to treat to prevent 1 event per year event of 9.

Although this observation comes from a nonprespecified combined analysis, "to me this result seems real, and I think it's a class effect that I'm willing to extrapolate to the SGLT2 inhibitors," Bhatt said. "It will change my practice," he added, by spurring him to more aggressively prescribe an SGLT2 inhibitor to a patient with T2D and HFpEF.

"I think there has been some hesitation to use SGLT2 inhibitors in T2D patients with HFpEF" because of the paucity of data in this population, even though labeling and society recommendations do not rule it out. "I hope this finding will move that needle, and also generally improve SGLT2 inhibitor uptake, which has been low," he said.

Also Safe Soon After Acute Heart Failure Decompensation

The other finding likely generalizable to SGLT2 inhibitors stems from the design of SOLOIST-WHF, which tested the efficacy and safety of starting sotagliflozin in patients with T2D as soon as they were stable after hospitalization for acute heart failure decompensation.

"Showing safety and efficacy when started in the hospital is pretty meaningful, because its tells patients that this drug is important and they should stay on it," which should improve adherence, predicted Bhatt, who is also executive director of Interventional Cardiovascular Programs at Brigham and Women's Hospital in Boston. "That's the ultimate treatment path to prevent patients from falling through the cracks" and failing to receive an SGLT2 inhibitor.

SOLOIST-WHF enrolled patients hospitalized for worsening heart failure who also required intravenous diuretic treatment but had become stable enough to transition to an oral diuretic and come off oxygen. During a median follow-up of just over 9 months (both SOLOIST-WHF and SCORED ended sooner than planned because of a change in drug company sponsorship), treatment with sotagliflozin cut the primary endpoint by a relative 33%, compared with placebo, and with an absolute reduction of 25 events per 100 patient-years for a number needed to treat of 4.

Sotagliflozin produced a strikingly high level of treatment efficiency driven by the high event rate in these recently decompensated patients. The benefit also appeared quickly, with a significant cut in events discernible within 28 days.

Extrapolating this finding to the SGLT2 inhibitors is "not a huge leap of faith," Bhatt said.

"There is a role for sotagliflozin in acute heart failure. It showed benefit in these high-risk, transition-phase patients," said Wilcox.

Simultaneously with Bhatt's presentation, results of SOLOIST-WHF and SCORED were published online in the New England Journal of Medicine.

The trials were sponsored initially by Sanofi, and more recently by Lexicon. Bhatt has received research funding from both companies, and also from several other companies. He also is an adviser to several companies. Wilcox has been a consultant to Boehringer Ingelheim and Medtronic.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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