Figure 3.
Limited therapeutic window to give anti-CD19 CAR T cells after PTCy. (A) Treatment schema that is identical to Figure 1B except that cryopreserved CAR T (or NT) cells were thawed and administered intravenously either on day +5, day +9, or day +14 post transplant to remove any potential confounding effects of variability in different CAR T-cell products or other aspects of the transplantation platform if these were done in parallel experiments. Splenocytes for transduction also came from CD45.1+CD45.2+ B6C3F1 mice to most definitively separate CAR+ (Protein-L+CD45.1+) from graft-derived (CD45.1−) T cells as wild-type (CD45.1−CD45.2+) B6C3F1 mice were used for the splenocytes and bone marrow for transplant. Mice not receiving cells on a given day received RPMI vehicle intravenously. (B) CAR T-cell administration on day +5, day +9, or day +14 to PTCy-treated mice did not aggravate histopathologic GVHD at day +21 compared with mice treated with PTCy without CAR T cells. (C) CAR T cells on day +5 significantly prolonged survival compared with mice not receiving CAR T cells (hazard ratio [HR] 0.29, P = .0022), mice receiving CAR T cells on day +9 (HR 0.33, P = .009) or day +14 (HR 0.19, P = .0003), or mice receiving NT cells on day +5 (HR 0.37, P = .02; NT-cell groups are shown in supplemental Figure 5). This prolonged survival was achieved without any significant difference in weights or clinical scores in the CAR T cells on day +5 group compared with these other groups. Meanwhile, CAR T cells administered on day +9 or day +14 did not prolong survival compared with the no CAR T or NT-cell groups. (D) Successful clearance of both benign and malignant CD19+ targets at day +21 was achieved only when CAR T cells were given on day +5. (E-F) Despite superior efficacy, viable donor CAR T cells were lowest in (E) total numbers and (F) percentages at day +21, particularly within the spleen, for the group administered CAR T cells on day +5. (F) Despite being the most highly proliferative, the lack of clinical activity of CAR T cells given on day +14 was associated with these CAR T cells at day +21 being (H-I) significantly less differentiated and (J-K) having significantly higher expression of coinhibitory molecules PD1 and LAG3 compared with CAR T cells administered on day +5 or day +9. Combined results of 3 independent experiments are shown for all parts with 5 mice per group per experiment for panel C and 4 mice per group per experiment for all other parts. Data underwent natural logarithmic (total numbers) or arcsin (percentages) transformation prior to one-way ANOVA followed by the Holm-Sidak post hoc test. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001, ∗∗∗∗P < .0001.

Limited therapeutic window to give anti-CD19 CAR T cells after PTCy. (A) Treatment schema that is identical to Figure 1B except that cryopreserved CAR T (or NT) cells were thawed and administered intravenously either on day +5, day +9, or day +14 post transplant to remove any potential confounding effects of variability in different CAR T-cell products or other aspects of the transplantation platform if these were done in parallel experiments. Splenocytes for transduction also came from CD45.1+CD45.2+ B6C3F1 mice to most definitively separate CAR+ (Protein-L+CD45.1+) from graft-derived (CD45.1−) T cells as wild-type (CD45.1−CD45.2+) B6C3F1 mice were used for the splenocytes and bone marrow for transplant. Mice not receiving cells on a given day received RPMI vehicle intravenously. (B) CAR T-cell administration on day +5, day +9, or day +14 to PTCy-treated mice did not aggravate histopathologic GVHD at day +21 compared with mice treated with PTCy without CAR T cells. (C) CAR T cells on day +5 significantly prolonged survival compared with mice not receiving CAR T cells (hazard ratio [HR] 0.29, P = .0022), mice receiving CAR T cells on day +9 (HR 0.33, P = .009) or day +14 (HR 0.19, P = .0003), or mice receiving NT cells on day +5 (HR 0.37, P = .02; NT-cell groups are shown in supplemental Figure 5). This prolonged survival was achieved without any significant difference in weights or clinical scores in the CAR T cells on day +5 group compared with these other groups. Meanwhile, CAR T cells administered on day +9 or day +14 did not prolong survival compared with the no CAR T or NT-cell groups. (D) Successful clearance of both benign and malignant CD19+ targets at day +21 was achieved only when CAR T cells were given on day +5. (E-F) Despite superior efficacy, viable donor CAR T cells were lowest in (E) total numbers and (F) percentages at day +21, particularly within the spleen, for the group administered CAR T cells on day +5. (F) Despite being the most highly proliferative, the lack of clinical activity of CAR T cells given on day +14 was associated with these CAR T cells at day +21 being (H-I) significantly less differentiated and (J-K) having significantly higher expression of coinhibitory molecules PD1 and LAG3 compared with CAR T cells administered on day +5 or day +9. Combined results of 3 independent experiments are shown for all parts with 5 mice per group per experiment for panel C and 4 mice per group per experiment for all other parts. Data underwent natural logarithmic (total numbers) or arcsin (percentages) transformation prior to one-way ANOVA followed by the Holm-Sidak post hoc test. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001, ∗∗∗∗P < .0001.

Close Modal
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal