The old antihypertensive drug verapamil may help reduce insulin requirements and hypoglycemic episodes in adults with type 1 diabetes, new research suggests.
Results from the study were published online July 9 as a research letter in Nature Medicine by Anath Shalev, MD, professor of medicine and director of the University of Alabama at Birmingham (UAB) Comprehensive Diabetes Center, and colleagues.
In the double-blind placebo-controlled Phase 2 clinical trial (NCT02372253), 26 adults with recent-onset (within 3 months) type 1 diabetes were randomized to oral verapamil or placebo added to insulin for 12 months.
The plan for the study was announced in 2014 and was based on more than a decade of work by the UAB team in animal models which suggested that verapamil, a calcium channel blocker, downregulates thioredoxin-interacting protein (TXNIP), which induces beta-cell apoptosis (cell death).
Verapamil therefore appears to bolster remaining endogenous beta-cell function, which has been shown to persist in people with type 1 diabetes longer than previously thought.
And in 2016, the same investigators reported the first human data from a large observational study in patients with type 1 or type 2 diabetes showing that those who took verapamil had lower average fasting serum glucose levels.
Now, with the current study, “Verapamil is the first therapy to have demonstrated a clinically significant effect preserving beta-cell function and the patient’s own insulin production in adults with type 1 diabetes,” Shalev told Medscape Medical News, stressing that the drug is “safe, well-tolerated, inexpensive, and readily available.”
At the same time, she cautioned, “Verapamil has been FDA-approved for over 30 years, but improved beta-cell function is still not an FDA-approved indication, and we therefore cannot recommend its generalized use for this indication. Nevertheless, patients with diabetes and their physicians will now be able to consider the pros and cons for its use in an individualized manner case by case.”
Verapamil Appears to Improve Beta-Cell Function
A total of 11 participants in the verapamil group and 13 participants in the placebo group completed the 1-year trial. Verapamil was started at a dose of 120 mg/day and titrated up, if tolerated, to a maximum of 360 mg/day.
The primary endpoint, endogenous beta-cell function, was assessed by measuring the mixed-meal tolerance test stimulated C-peptide area under the curve at baseline, 3 months, and 12 months.
After adjustment for any pre-existing differences at baseline, stimulated C-peptide was significantly greater in the verapamil group compared with the placebo group at both 3 and 12 months (P = .0334 and P = .0377, respectively).
And within each individual from baseline to 3 and 12 months, the verapamil-treated participants maintained a significantly higher percentage of stimulated C-peptide area under the curve compared with the placebo group (P = .0491 and P = .0451, respectively).