MajesTEC-3 Trial Results and Earlier-Line Treatment Evidence

Dr. Costa discusses evolution from initial single-arm bispecific experience in heavily pretreated patients to recent earlier-setting data. The pivotal MajesTEC-3 trial led to FDA approval of teclistamab-daratumumab for relapsed/refractory multiple myeloma after at least one prior therapy line, representing significant treatment landscape advancement.

MajesTEC-3 enrolled patients different from triple-class refractory populations, requiring proteasome inhibitor and lenalidomide exposure with lenalidomide-refractory disease after one prior line. More than 85% had lenalidomide-refractory disease but were CD38 antibody-naïve or non-refractory. The trial randomized approximately 600 patients between standard daratumumab-based treatments versus teclistamab-daratumumab combination.

Key findings included modified teclistamab scheduling mirroring daratumumab dosing, positively impacting safety and efficacy. The combination demonstrated remarkable superiority with hazard ratio 0.17 for progression-free survival and early overall survival benefit. Three-year progression-free survival reached 83%, creating flat-line curves suggesting minimal progression beyond 2 years.

Results differ dramatically from late-line monotherapy showing early drops, instead demonstrating over 90% response rates with sustained stability. Safety analysis addressed T-cell engager plus CD38 antibody combination concerns. Although increased infections occurred, overall fatal adverse events were similar between arms despite longer exposure. Temporal analysis revealed higher-grade infections during first 6 months, but rates beyond 6 months became nearly identical, indicating disease burden as primary infection contributor. Mid-trial amendments emphasizing immunoglobulin prophylaxis dramatically improved outcomes.