“I think we have lots of potential to improve people’s quality of life who are living with type 1 diabetes if we can increase their endogenous insulin secretion. ... I think long-term combination therapy is going to be the answer,” study author Emily K. Sims, MD, a pediatric endocrinologist at Indiana University, Indianapolis, said in an interview.
DFMO inhibits the polyamine biosynthesis pathway, which plays a role in the inflammatory responses in autoimmune diseases, including type 1 diabetes. It’s sold under the name eflornithine as an intravenous treatment for African sleeping sickness (trypanosomiasis) and as a cream for unwanted hair growth in women. It also has orphan designations for treating various cancers, including neuroblastoma.
In type 1 diabetes, the immune system destroys insulin-producing pancreatic beta cells. Insulin treatment is required. Recently, the monoclonal antibody teplizumab (Tzield, Sanofi) was approved as a treatment for delaying the onset of type 1 diabetes in people with autoantibodies that signify a preclinical stage of the condition. As yet, no agent has been approved for preserving beta-cell function after the onset of type 1 diabetes, but many are under investigation.
The new safety study by Dr. Sims and colleagues, which was published in Cell Medicine Reports, enrolled 41 people with type 1 diabetes who had been diagnosed within the previous 8 months, including 31 children. Participants were randomly assigned to undergo oral treatment with DFMO at one of five doses or placebo for 3 months, with 3 additional months of follow-up.
Following a mixed-meal tolerance test at 6 months, the C-peptide area under the curve – a measure of beta-cell function – was significantly higher with the three highest DFMO doses compared to placebo (P = .02, .03, and .02 for 125 mg/m2, 750 mg/m2, and 1,000 mg/m2, respectively).
Two individuals dropped out, one because of anaphylaxis. There were no dose-limiting toxicities or serious adverse events, while mild gastrointestinal events, anemia, and headache were common. “Although there’s no [Food and Drug Administration] approval for the oral form right now, there’s a lot of safety data, including in kids from the neuroblastoma studies,” Dr. Sims explained.
There were no differences in C-peptide at 3 months or in hemoglobin A1c at any time point. Glucose areas under the curve were significantly lower for DFMO, compared with placebo in the 125-mg/m2 and 750-mg/m2 treatment groups at the 6-month time point (P = .03 and .04, respectively).
In their article, Dr. Sims and colleagues also reported confirmatory analyses in mice, as well as testing in the humans showing that there didn’t appear to be significant immune system modulation. “So, we can envision giving DFMO in addition to something that targets the immune system, as a combination therapy,” said Dr. Sims, who also worked on the pivotal study of teplizumab.
“I’m excited. The sample size is small, so I was kind of expecting no efficacy signals. ... It’s definitely worth following up,” she said.
However, she noted, “it wasn’t a slam-dunk huge effect. It was subtle. It seemed that things were kind of more stable compared to placebo over time versus ... a big increase in C-peptide over time.”
But, she added, “I believe that even teplizumab will need to be used in combination. It delays the onset of type 1 diabetes and improves C-peptide, but it didn’t get everyone off insulin. I don’t think we’ve seen any drug that won’t need to be used in combination.”
Dr. Sims pointed to other investigational agents, such as verapamil and various Janus kinase inhibitors, that may also serve in combination to forestall or reduce insulin dependency for people with either new-onset type 1 diabetes or those who have been identified via screening as having type 1 diabetes–related autoantibodies. “I think there are a lot of potential different interventions.”
Dr. Sims and colleagues are now conducting a larger six-center JDRF-funded study of DFMO in early-onset type 1 diabetes that will be fully powered and that will use the highest tolerated doses from the preliminary study.
She believes there will likely be benefit even if the agent doesn’t completely reverse the disease. “The people who are making more insulin are just easier to manage, with more time in range and less hypoglycemia.” Even if the drugs only delay but don’t prevent type 1 diabetes entirely in those at risk, “the improvement in quality of life of being able to delay insulin for a few years is really palpable. ... I’m really optimistic.”
Dr. Sims disclosed no relevant financial relationships. Three other authors are coauthors on a patent application for the use of DFMO for the treatment of beta-cell dysfunction in type 1 diabetes; one of those three authors is an employee of Cancer Prevention Pharmaceuticals.
A version of this article first appeared on Medscape.com.