Table 3.
Tumor Response According to Dose of Chimeric Antigen Receptor–Positive (CAR+) T Cells.*
| Variable | 50×106 CAR+ T Cells (N = 3) | 150×106 CAR+ Tells (N = 8) | 450×106 CAR+ T Cells | 800×106 CAR+ T Cells (N = 3) | 150×106–800×106 CAR+ T Cells (N = 30) | 50×106–800×106 CAR+ T Cells (N = 33) | |
|---|---|---|---|---|---|---|---|
| <50% BCMA (N = 8)† | ≥50% BCMA (N = 11)† | ||||||
| Objective response‡ | |||||||
| No. of patients with a response | 1 | 6 | 8 | 10 | 3 | 27 | 28 |
| Rate ― % (95% CI) | 33 | 75 | 100 | 91 | 100 | 90 | 85 |
| (1–91) | (35–97) | (63–100) | (59–100) | (29–100) | (74–98) | (68–95) | |
| Best overall response ― no. (%) | |||||||
| Stringent complete response | 0 | 5 (63) | 3 (38) | 4 (36) | 0 | 12 (40) | 12 (36) |
| Complete response | 0 | 0 | 0 | 1 (9) | 2 (67) | 3 (10) | 3 (9) |
| Very good partial response | 0 | 0 | 4 (50) | 4 (36) | 1 (33) | 9 (30) | 9 (27) |
| Partial response | 1 (33) | 1 (12) | 1 (12) | 1 (9) | 0 | 3 (10) | 4 (12) |
| Stable disease | 2 (67) | 1 (12) | 0 | 1 (9) | 0 | 2 (7) | 4 (12) |
| Progressive disease | 0 | 1 (12) | 0 | 0 | 0 | 1 (3) | 1 (3) |
| Median duration of response (95% CI) — mo | 1.9 (NE–NE) | NE | 7.7 (5.3–14.8) | 12.9 (10.9–12.9) | 10.9 (7.2–NE) | 10.9 (7.2–NE) | |
| Negativity for MRD § | |||||||
| No. of patients with a response who could be evaluated for MRD | 0 | 4 | 11 | 1 | 16 | 16 | |
| Rate ― % | 0 | 100 | 100 | 100 | 100 | 100 | |
All responses were confirmed and assessed according to the International Myeloma Working Group Uniform Response Criteria for Multiple Myeloma (details on the criteria for disease response are provided in the Supplementary Appendix). Percentages may not total 100 because of rounding. MRD denotes minimal residual disease, and NE could not be estimated.
Data are for BCMA expression on bone marrow plasma cells at screening.
An objective response was defined as a partial response or better.
Negativity for MRD was defined by a sensitivity level of at least 10−4 nucleated cells on the next-generation sequencing assay clonoSEQ (Adaptive Biotechnologies); 15 patients were MRD-negative at 10−5 (indeterminate, 1 patient), and 3 were MRD-negative at 10−6 (indeterminate, 10 patients). A total of 12 of the 16 patients who had a response and were MRD-negative had at least two MRD-negative assessments. Reasons that MRD could not be evaluated were an inability to detect the malignant clone in the baseline bone marrow aspirate, which made follow-up evaluation impossible (in 7 patients), failure of the MRD result in quality-control testing (in 2 patients), and nonreceipt of the bone marrow aspirate sample (in 6 patients).