SAN FRANCISCO – The dipeptidyl peptidase-4 inhibitor linagliptin (Tradjenta) is safe on the kidneys, the cardiovascular system, and in older people with type 2 diabetes, according to findings presented at the annual scientific sessions of the American Diabetes Association.
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Dr. Mark Cooper
Investigators in the international Cardiovascular and Renal Microvascular Outcome Study with Linagliptin (CARMELINA) randomized 6,979 patients with type 2 diabetes who also had cardiovascular and/or kidney disease 1:1 to daily oral linagliptin 5 mg or placebo on top of standard of care, and they followed them for a median of 2.2 years. The mean age was 65.9 years, baseline hemoglobin A1c was 8.0%, and disease duration was about 15 years. Almost 63% of the patients were men, and about a quarter had a history of heart failure at baseline (JAMA. 2019;321[1]:69-79).
The study was unusual among other DPP-4 trials in that almost 60% of the patients were older than 65 years and 62.3% had impaired renal function with an estimated glomerular filtration rate (eGFR) of less than 60 ml/min per 1.73 m2.
There was no increased risk with linagliptin, compared with placebo, in the primary composite outcome of cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction (12.4% vs. 12.1%, respectively; hazard ratio, 1.02; P = .74), and there was no difference between the individual components even when broken down by age (younger than 65, 65-75, or older than 75 years) or by renal function (eGFR 60 or more, 45 to less than 60, 30 to less than 45, or less than 30 ml/min per 1.73 m2), according to investigator Mark Cooper, MBBS, PhD, of the department of diabetes at Monash University, Melbourne, who presented the findings.
There was no increase in the number of hospitalizations for heart failure with linagliptin, compared with placebo (6% vs. 6.5%, respectively; HR, 0.90; P = .26) – a concern with some DPP-4 inhibitors – and no increase in hypoglycemia (just over a quarter in both groups), even when broken down by age and renal function.
A decrease in albuminuria with linagliptin held across all renal subgroups. It is not known if that was because of glucose lowering or some other effect, but Dr. Cooper said he believed there was “a modest renal protective effect, [although] not at the level one would expect to translate into hard renal outcomes.”
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Dr. Robert Eckel
Robert Eckel, MD, a professor of medicine at the University of Colorado at Denver, Aurora, who moderated the session, said the results were reassuring. “Ultimately, linagliptin seems safe,” even in older people with reduced eGFR. “It does not improve cardiovascular outcomes, but based on many DPP-4 trials, we didn’t expect it to,” he said.
“I don’t think DPP-4s are going to fall into any different place in the [treatment] algorithm” based on these results, he added. The class is currently third-line after metformin or insulin, followed by sodium-glucose cotransporter 2 inhibitors or glucagonlike peptide–1 receptor agonists for cardiovascular protection.
“When we look at [cardiovascular outcomes], ultimately, the SGLT2 inhibitors and the GLP-1 receptor agonists win,” he said. In addition, the blood glucose effects of linagliptin are “pretty modest, so if lowering hemoglobin A1c is the focus, this drug would be lower down on the list.”
Overall, linagliptin “falls into a lesser class, but a safe class for certain circumstances,” said Dr. Eckel, who gave the example of a woman in her late 70s with moderate to severe kidney function, an HbA1c level of 7.9%, and no cardiovascular disease. Her HbA1c might get down to 7.6% or so with linagliptin, he said, “but I’m not sure we have absolute proof of the benefit” of such a modest decline.
Boehringer Ingelheim, the maker of linagliptin, funded the study. The presenter disclosed honoraria, speaking fees, and grants from the company. A number of the investigators were employees of the company.