A Food and Drug Administration advisory panel has endorsed a pancreatic islet cell transplant therapy for the treatment of people with type 1 diabetes that can’t be managed with current therapies.
On April 15, the FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee voted 12 to 4 in favor of approval of donislecel (Lantidra). There was one abstention. The panel regarded the drug as having “an overall favorable benefit-risk profile for some patients with type 1 diabetes.” The product consists of purified allogeneic pancreatic islets of Langerhans derived from cadaveric donors and is infused into the portal vein of the liver.
Benefits of the treatment include the potential for insulin independence and elimination of severe hypoglycemia. Risks are those associated with the surgical procedure and with long-term immunosuppression.
The therapy is manufactured by CellTrans. According to Jose Oberholzer, MD, the founder of CellTrans, the proposed indication is for adults with “brittle” type 1 diabetes who meet the American Diabetes Association’s (ADA) criteria for whole-organ pancreas-alone transplant (i.e., transplant of pancreas but not kidney).
The ADA criteria include the following: frequent, severe hypoglycemia, hyperglycemia, and/or ketoacidosis that requires medical attention; clinical or emotional problems regarding the use of exogenous insulin; and consistent failure of insulin-based management to prevent acute diabetes complications.
Success in two-thirds of patients in small studies
Dr. Oberholzer presented data from two single-arm open-label studies: a phase 1/2 trial initiated in 2004 with 10 patients, and a phase 3 study with 20 patients that began in 2007. The inclusion criteria differed somewhat between the two studies, but all 30 patients had hypoglycemic unawareness. Mean follow-up was 7.8 years for the phase 1/2 trial and 4.7 years for the phase 3 trial.
For all of the patients, C-peptide levels were positive after transplant. The composite endpoint for success – an A1c level of ≤ 6.5% and the absence of severe hypoglycemic episodes for 1 year – was met by 19 patients (63.3%). For five patients (16.7%), the target A1c level was not achieved, and seven patients (23.3%) experienced a severe episode of hypoglycemia.
Twenty of the 30 patients achieved insulin independence for at least 1 year.
Improvements were also seen at 1 year in mixed meal test outcomes, fasting blood glucose levels, and overall glycemic control. Graft survival 10 years post transplant was achieved by 60% of patients, Dr. Oberholzer said.
Adverse events not unexpected, but still of concern
Two patients died, one as a result of fulminant sepsis at 20 months post transplant, and the other as a result of severe dementia 9 years post transplant. Three patients experienced four serious procedure-related events, including one liver laceration and two hepatic hematomas. Elevations in portal pressure occurred in two patients.
Most adverse events were associated with immunosuppression. These included 178 infections in 26 of the 30 patients. The most common of these were herpes virus infections, Epstein-Barr virus infections, oral candidiasis, and cytomegalovirus infections. Twelve infections were severe. Renal function declined persistently in two patients (20%), and six (20%) experienced new-onset proteinuria at 1 year.
The adverse events related to the procedure and the problems associated with immunosuppression were not unexpected and were consistent with those described for patients receiving whole pancreas transplants, FDA reviewer Patricia Beaston, MD, said in her review of the CellTrans data.