TABLE 2.
Coprimary Pharmacokinetic and Key Efficacy End Points
| End Point | Subcutaneous Group (n = 206) | Intravenous Group (n = 212) | Treatment Effect (95% CI) | P |
|---|---|---|---|---|
| Coprimary pharmacokinetic end pointsa | ||||
| Ctrough, µg/mL (%CV) | Geometric mean ratio (90% CI) | |||
| Cycle-2-day-1 | 365 (33) | 314 (32) | 1.15 (1.04 to 1.26) | |
| Cycle-4-day-1 (steady state) | 224 (39) | 162 (42) | 1.43 (1.27 to 1.61) | |
| AUCD1-D15, µg·h/mL (%CV) | Geometric mean ratio (90% CI) | |||
| Cycle 2 | 142,236 (31) | 135,552 (24) | 1.03 (0.98 to 1.09) | |
| Secondary end points | ||||
| Objective responseb | ||||
| Patients, % (95% CI) | 30 (24 to 37) | 33 (26 to 39) | Relative risk for noninferiority, 0.92 (0.70 to 1.23)c | .001 |
| Progression-free survival | ||||
| Median, mo (95% CI) | 6.1 (4.3 to 8.1) | 4.3 (4.1 to 5.7) | HR, 0.84 (0.64 to 1.10) | .20 |
| Patients, % (95% CI) | ||||
| At 6 months | 50 (43 to 58) | 42 (35 to 50) | ||
| At 12 months | 37 (28 to 46) | 20 (8 to 35) | ||
| Overall survival | ||||
| Median, mo (95% CI) | 12.9 (12.9 to NE) | NE (10.2 to NE) | HR, 0.62 (0.42 to 0.92)d | .02d |
| Patients, % (95% CI) | ||||
| At 6 months | 85 (79 to 89) | 75 (68 to 80) | ||
| At 12 months | 65 (52 to 74) | 51 (37 to 64) | ||
Abbreviations: %CV, % coefficient of variation; AUCD1-D15, area under the curve from cycle-2 day-1 to day-15; Ctrough, observed serum concentration of amivantamab at steady state; EGFR, epidermal growth factor receptor; Ex19del, exon 19 deletion; HR, hazard ratio; NE, not estimable; TKI, tyrosine kinase inhibitor.
The pharmacokinetic population for evaluating the coprimary pharmacokinetic end points included all patients who received all doses without dose modifications before the respective end point and who provided the pharmacokinetic samples necessary to derive each parameter. The efficacy population included all the patients who had undergone random assignment.
The objective response (complete or partial response as best response) was assessed by the investigator among all responders.
Odds ratio (95% CI), 0.87 (0.58 to 1.32); P = .52. P value is calculated via a logistic regression model stratified by brain metastases at baseline (yes v no), EGFR mutation (L858R v Ex19del), race (Asian v non-Asian), and last therapy (osimertinib [or another third-generation EGFR-TKI] v chemotherapy).
For overall survival, 95% CIs were not adjusted for multiplicity and should not be used in place of hypothesis testing; P value is nominal.