Hadar, Nira

e19553 Background: The combination of tafa + LEN has accelerated approval in the United States (2020) and conditional approval in Canada and Europe (2021) for R/R DLBCL in ASCT-ineligible adult pts. A tolerable safety profile for R-CHOP + tafa ± LEN in pts with newly diagnosed DLBCL in the Phase Ib First-MIND study (NCT04134936) was previously reported, with numerically superior efficacy for R-CHOP + tafa + LEN (ASH 2021; #3556). We report PK, PD, and immunogenicity of R-CHOP + tafa ± LEN in this first line setting. Methods: Eligible pts ≥18 years with treatment-naïve DLBCL, IPI 2–5, and ECOG PS 0–2 were randomized 1:1 to either six 21-day (D) cycles (C) of R-CHOP (R-CHO, D1; P, D1–5) + tafa (12 mg/kg IV, D1, 8, 15) (Arm A) or R-CHOP + tafa + LEN (25 mg orally, D1–10) (Arm B). Secondary endpoints included tafa serum conc and number and percentage of pts developing anti-tafa Abs. Exploratory endpoints included natural killer (NK) cell, T-cell, and B-cell count in peripheral blood. Results: Data cut-off: 13 March 2021 for safety analysis, incl. ≥1 month follow-up after EoT visit for all pts; 15 September 2021 for efficacy. Tafa serum conc reached steady state by C3 (geometric mean trough conc: Arm A, 186.40–216.55 µg/mL; Arm B, 171.77–201.54 µg/mL) and steadily declined after treatment completion. Anti-tafa Abs were detected in 1/65 (1.5%) pts. This pt showed pre-existing tafa Abs at baseline, which decreased during treatment. Median NK cell count decreased from baseline at C1D8 but was at baseline or higher levels by EoT visit (Arm A) and C1D15 (Arm B; Table). T-cell count decreased from baseline at C1D8 in both arms but was at baseline level or higher by C1D15 (Arm A) and EoT visit (Arm B). Median B-cell count decreased from baseline to 0 cells/μL (Arm A, C1D15; Arm B, C1D8); at 6-month follow-up after EoT visit, B-cell count had recovered to measurable levels in ̃50% of pts. Conclusions: Tafa serum conc reached and maintained a therapeutic dose level in this first-line regimen and declined in line with known tafa half-life (̃16 days) after treatment completion; tafa levels were comparable between the two treatment arms. No pt developed treatment-induced or treatment-boosted anti-tafa Abs. Median NK-cell, T-cell, and B-cell counts were comparable between treatment arms in all cycles. Clinical trial information: NCT04134936. [Table: see text]

TPS7590 Background: Up to 40% of patients relapse or are refractory (R/R) to R-CHOP, the current standard of care for diffuse large B-cell lymphoma (DLBCL), indicating an unmet need, particularly in patients with high-intermediate and high-risk disease (IPI 3–5). POLARIX (NCT03274492) evaluated a modified regimen substituting polatuzumab vedotin for vincristine (pola-R-CHP), demonstrating modest improvement in PFS with no OS benefit between treatment arms. The addition of lenalidomide (LEN) to R-CHOP improved both PFS and OS in the ECOG-ACRIN E1412 trial but not in the Phase III ROBUST study, in which a lower dose of LEN was used, despite a positive trend toward 2-year PFS in a subgroup analysis. The chemo-free immunotherapy tafasitamab + LEN has received accelerated approval in the United States (2020), and conditional marketing authorization in Europe and Canada (2021) in adult patients with R/R DLBCL ineligible for ASCT based on L-MIND (NCT02399085). The primary analysis of First-MIND (NCT04134936), a Phase Ib randomized safety study of R-CHOP + tafasitamab ± LEN in patients with previously untreated and newly diagnosed DLBCL, demonstrated that adding tafasitamab + LEN does not impair dosing and scheduling of R-CHOP, with toxicities similar to those expected with R-CHOP alone (ASH 2021; #3556). frontMIND (NCT04824092) will investigate the efficacy and safety of R-CHOP + tafasitamab + LEN vs R-CHOP alone in previously untreated patients with high-intermediate and high-risk DLBCL. Methods: frontMIND is a Phase III, multicenter, randomized, double-blind, placebo-controlled study. Approximately 880 patients are planned to be randomized at ̃350 centers in North and South America, Europe, and Asia-Pacific. Eligible patients aged 18‒80 years with previously untreated local biopsy-proven, CD20+ DLBCL with IPI score 3–5 (age-adjusted IPI 2–3 if ≤60 years), and ECOG PS 0–2 will be enrolled. Patients with transformed lymphoma (except double or triple hit lymphoma) are excluded. Patients will be randomized 1:1 to receive six 21-day (D) cycles of either R-CHOP + tafasitamab (12 mg/kg intravenously, D 1, 8, and 15) + LEN (25 mg orally, D1–10) or R-CHOP + tafasitamab and LEN placebos. Patients will be followed for up to 5 years after the end of treatment. The primary endpoint is investigator-assessed PFS. Secondary endpoints include investigator-assessed event-free survival, OS, safety, and tafasitamab serum concentration (trough and Cmax levels). Sensitivity and specificity of minimal residual disease for early detection of disease progression is an exploratory endpoint; further MRD parameters may also be investigated. The study is funded by MorphoSys AG and conducted with the scientific support of members of the Fondazione Italiana Linfomi and the German Lymphoma Alliance. Clinical trial information: NCT04824092.