Pfizer Inc. and Servier Laboratories Ltd presented early results from two phase 1 studies of their experimental CAR-T therapy at the American Society of Hematology conference in Atlanta, showing the treatment to be safe and tolerable.
The chimeric antigen receptor T-cell treatment UCART19 showed 83% complete remission rate — when tests, physical exams and scans show that signs of cancer are gone — in patients with a type of hard-to-treat leukemia.
The Calm study is evaluating the safety, tolerability and anti-leukemic activity of UCART19 in adult patients with relapsed or refractory CD19-positive B-cell acute lymphoblastic leukemia, or r/r B-ALL. Twenty-eight days after receiving the therapy, five out of seven patients in the trial achieved negative minimal residual disease, or MRD — a measurement of residual disease cells after treatment.
"These early results for UCART19 are very encouraging both in terms of manageable safety and the impressive complete molecular remission rate in these hard-to-treat adult patients with R/R B-ALL," said Reuben Benjamin, principal investigator of the Calm study.
One patient died on the 15th day after developing grade 4 cytokine release syndrome, a toxic reaction to the reinfused cells that can sometimes be deadly, and an inflammatory response complication called neutropenic sepsis.
The other phase 1 trial, called Pall, is evaluating the safety and ability of UCART19 in inducing negative MRD in pediatric patients with high-risk r/r B-ALL to enable allogeneic stem cell transplantation. All five children in this trial achieved MRD negativity at day 28, enabling them to proceed to the stem cell transplantation.
Servier is the sponsor of both studies that are ongoing in Europe and the U.S.
In November 2015, Servier acquired the exclusive rights to UCART19 from Cellectis SA. Following further agreements, Servier and Pfizer began collaborating on a joint clinical development program for this gene-engineering cancer therapy.
Pfizer has been granted exclusive rights by Servier to develop and commercialize UCART19 in the U.S., while Servier retains exclusive rights for all other countries.
