‘Beautiful data’ seen in two patients, with ‘transformational’ potential
Asked to comment, Marlon Pragnell, PhD, vice president for Research & Science at the ADA, told this news organization: “It’s beautiful data. People who have type 1 diabetes lack [pancreatic] beta cells ... it was impossible to get sufficient beta cells from cadaveric transplants. It’s just nowhere near enough. If this is safe and effective, if they continue to show safety and efficacy like patient 1, this will be transformational.”
Dr. Markmann presented data for the most recent study visit for each of the two patients, 270 days for patient 1 and 150 days for patient 2. Prior to the transplants, patient 1 had experienced five severe hypoglycemic events and patient 2 had experienced three.
Both had undetectable C-peptide levels at baseline. In response to a mixed-meal tolerance test, patient 1 showed a “robust” C-peptide response by day 90, which increased by day 180. Those levels had dropped but were still detectable by day 270, “possibly due to improved insulin sensitivity,” Dr. Markmann said.
Similarly, Patient 2 also had increased C-peptide that increased to detectable range by day 90 with improved glucose disposal.
Hemoglobin A1c dropped in patient 1 from 8.6% at baseline to 6.9% at day 180, to a “remarkable” 5.2% at day 270. For patient 2, the drop was from 7.5% to a nadir of 6.4% by day 57, then reversing back to 7.1% at day 150.
Both patients also had significant reductions in insulin dose. For patient 1, the dose reduction was more than 90% – from 34 units at baseline to 2.6 units by day 90. By day 210 he was able to stop insulin and by day 270 he met formal criteria for insulin independence.
Patient 2 also had a significant reduction in insulin dose, from 25.9 units to 18.7 by day 57 and remained stable thereafter, at 18.2 units by day 150.
Asked why Patient 2’s results weren’t quite as impressive as patient 1’s, Dr. Markmann replied “I think what’s important is that both patients did great. And since this was a half-dose, we might have expected that the outcome was going to be more like patient 2 rather than patient 1. So, I think we’re just going to have to [study this in] more patients to understand where it falls.”
Although patient 1 experienced a cluster of six severe hypoglycemic events early in the posttransplant period, he had no further events after day 35. Patient 2 had no severe hypoglycemic events.
Other safety events were generally consistent with that seen with the immunosuppressive regimen in the perioperative period. Patient 1 had a “mild and self-limited” rise in liver function test and also experienced two severe adverse events: A rash from the immune suppression that resolved spontaneously, and dehydration requiring hospitalization on day 186. Patient 2’s adverse events were all mild to moderate, most commonly headache and hypomagnesemia and not related to VX-880.
[embed:render:related:node:248096]
Immunosuppression: Work is ongoing
The immunosuppression regimen used comprises a depletion of lymphocytes at induction, followed by a maintenance regimen of two standard agents used in kidney transplant patients and found to be well tolerated, Dr. Markmann said.
Still, the risk of immunosuppression generally outweighs the potential benefit for most people with type 1 diabetes who are managing reasonably well with insulin treatment.
“This is part one of a two-part problem. One is to have a reliable, consistent, effective cell therapy. The second is to develop an approach that doesn’t require immunosuppression. ... But if we had a way of transplanting the cells without the need for immunosuppression, then it could be really widely available. That’s an opportunity for the future since these cells can be made in unlimited quantities,” Dr. Markmann commented during the press briefing.
Asked for his thoughts about the immunosuppression aspect, Dr. Pragnell told this news organization: “Immune suppression is a concern, but I feel that this is just the start of so much research in this area. They’re going to take this step by step. This is just the start. My understanding is they have additional strategies around immune suppression, and in the future they might not even need immunosuppression. But even at this stage right now, it’s amazing.”
He added: “The ‘artificial pancreas’ is a huge step forward, but it’s just a bridge to a cure, whereas if they’re able to show safety and efficacy, this is potentially a cure. ... I’m very excited about it.”
Dr. Markmann serves on advisory boards for iTolerance, eGenesis, and QihanBio. He is a consultant to Vertex Pharmaceuticals. Dr. Pragnell is an ADA employee and has no further disclosures.
A version of this article first appeared on Medscape.com.