Belgium based Celyad just announced that they have observed a complete response in a patient with relapsed refractory acute myeloid leukemia after treatment with the first cell dose-level of only 3×108 NKG2D T-cells. The company so far has treated a total of 3 blood cancer patients so this represents a quite impressive response rate in a very hard to treat cancer setting, where survival is measured in months rather than in years. Celyad’s dose escalation scheme goes from 3×108, 1×109 up to 3×109 cells. So the response occurred at only one tenth of the target dose.
Christian Homsy, CEO of Celyad comments: “We are pleased to have demonstrated the first objective clinical response of CYAD-01 (a.k.a. CAR-T NKG2D) as this is the very first time a relapsed, refractory AML patient has reached a MLFS with gene-engineered T cells without pre-conditioning lymphodepletion nor additional other concurrent treatment to CYAD-01 administration. This success further reinforces our confidence in our approach and the validity of NKG2D ligands as a target. We will now use the collected data to move forward with the next stage of our product development: reinforcing responses in as many clinical settings as possible.”
At each dose, the patients receive three successive administrations, two weeks apart at the specified dose. Overall, 14 patients have been dosed. Celyad has reported one grade 3 and one grade 4 event but both resolved within 72 hours. No dose limiting toxicities or deaths related to the treatment occurred. Compared to toxicities seen in CD19 programs, which exhibit grade 3+ toxicities in the 20ies and 30ies, the treatment seems to have a rather benign safety profile.