Table 2.
Summary of Response Rates and Minimal Residual Disease Status in the Intention-to-Treat Population.*
| Variable | Daratumumab Group (N = 368) | Control Group (N = 369) | P Value |
|---|---|---|---|
| Overall response — no. (% [95% CI]) | 342 (92.9 [89.8–95.3]) | 300 (81.3 [76.9–85.1]) | <0.001† |
| Best overall response — no. (%) | |||
| Complete response or better | 175 (47.6) | 92 (24.9) | <0.001† |
| Stringent complete response‡ | 112 (30.4) | 46 (12.5) | — |
| Complete response | 63 (17.1) | 46 (12.5) | — |
| Very good partial response or better | 292 (79.3) | 196 (53.1) | <0.001† |
| Very good partial response | 117 (31.8) | 104 (28.2) | — |
| Partial response | 50 (13.6) | 104 (28.2) | — |
| Stable disease | 11 (3.0) | 56 (15.2) | — |
| Progressive disease | 1 (03) | 0 | — |
| Response could not be evaluated | 14 (3.8) | 13 (3.5) | — |
| Negative status for minimal residual disease — no. (%)§ | 89 (24.2) | 27 (7.3) | <0.001¶ |
Response was assessed on the basis of International Myeloma Working Group recommendations (details on the criteria for disease responses are provided in the protocol). The following secondary end points were tested sequentially, each with an overall two-sided alpha level of 0.05, with the use of a hierarchical testing approach: complete response or better, very good partial response or better, negative status for minimal residual disease, and overall response.
The P value was calculated with the use of the Cochran–Mantel–Haenszel chi-square test.
Criteria for a stringent complete response include the criteria for a complete response plus a normal free light-chain ratio and absence of clonal plasma cells, as assessed by immunofluorescence or immunohistochemical analysis or by two-color to four-color flow cytometry.
The threshold for minimal residual disease was defined as 1 tumor cell per 105 white cells. Status regarding minimal residual disease is based on a postrandomization assessment performed on bone marrow samples with the use of a validated next-generation sequencing assay (clonoSEQ Assay, version 2.0; Adaptive Biotechnologies) in accordance with International Myeloma Working Group guidelines on assessment of minimal residual disease.23
The P value was calculated with the use of the Fisher’s exact test.