Phase 3 study (inMIND) of tafasitamab plus lenalidomide and rituximab for relapsed or refractory follicular lymphoma: Clinical characteristics and outcomes of patients receiving second-line treatment

Abstract Introduction: In patients (pts) with follicular lymphoma (FL) durability of response in second-line (2L) therapy is important, as prognosis worsens and burden increases with subsequent lines of therapy. Chemoimmunotherapy is often used as 1L; however, immunotherapy is preferred for relapsed or refractory (R/R) FL. Tafasitamab (tafa) is a humanized CD19-targeting monoclonal antibody (mAb) recently approved in combination with lenalidomide (len) + rituximab (R) for treatment of adult pts with R/R FL in the US. The primary analysis from the inMIND (NCT04680052) study demonstrated significant improvement in investigator-assessed PFS in pts with R/R FL representing a 57% reduction in the risk of progression or death, with a safety profile as expected for the pt population (Sehn LH, et al. Blood. 2024;144[Suppl 2]:LBA1). This post hoc analysis evaluates efficacy and safety outcomes from inMIND in pts with R/R FL who had received 1 prior line of therapy. Methods: Pts aged ≥18 years with R/R CD19+ and CD20+ FL (grade 1-3A), ECOG PS ≤2, and who had received ≥1 prior systemic therapy including an anti-CD20 mAb were eligible. Pts were randomized 1:1 to receive tafa 12 mg/kg IV or placebo (pbo) with standard dosing of len+R for up to 12×28-day cycles. Analyses in pts who received 2L treatment included investigator-assessed PFS (primary endpoint), PFS by IRC, PET-CR rate (FDG-avid population), ORR, TTNT, and safety. Results: Of 548 pts randomized to the tafa arm (n=273) or pbo arm (n=275), 300 (55%) had only 1 prior line of therapy (tafa, n=147; pbo, n=153). Baseline characteristics in the 2L pt subgroup were generally consistent with the overall FL study population and balanced between treatment arms: median age 65 y (range, 31-88); 56% male; 77% intermediate- or high-risk FLIPI; 81% high tumor burden per GELF criteria; 43% POD24 (progression within 24 months of start of initial treatment). In this 2L pt subgroup, median investigator-assessed PFS was improved with the addition of tafa vs pbo (24.0 months vs 15.4 months [hazard ratio (HR) (95% CI) 0.40 (0.26, 0.62)]). Median PFS by IRC (not reached [NR] vs 20.7 months; HR [95% CI] 0.44 [0.28, 0.70]), PET-CR rate (50.7% vs 43.4%; odds ratio [OR] [95% CI] 1.3 [0.84, 2.15]), ORR (86.4% vs 73.9%; OR [95% CI] 2.3 [1.26, 4.17]), and median TTNT (NR vs 28.8 months; HR [95% CI] 0.52 [0.32, 0.84]) were also improved with addition of tafa vs pbo among 2L pts. Outcomes were also evaluated in pts receiving prior anti-CD20 plus chemotherapy as 1L therapy (tafa, n=122; pbo, n=132). Analysis was not performed in pts who received anti-CD20 monotherapy in 1L due to small numbers (tafa, n=26; pbo, n=20). Median investigator-assessed PFS was higher with addition of tafa vs pbo in 2L pts who received 1L anti-CD20+chemo (24.0 months vs 14.4 months; HR [95% CI] 0.45 [0.29, 0.71]). Pts receiving 1L anti-CD20+chemo also had higher median PFS by IRC (not reached [NR] vs 20.1 months; HR [95% CI] 0.51 [0.31, 0.82]), PET-CR rate (52.2% vs 41.6%; odds ratio [OR] [95% CI] 1.6 [0.95, 2.66]), ORR (86.9% vs 71.2%; OR [95% CI] 2.8 [1.40, 5.45]), and median TTNT (NR vs 28.8 months; HR [95% CI] 0.52 [0.31, 0.86]) with addition of tafa vs pbo. Among 2L pts with POD24, median investigator-assessed PFS was improved with the addition of tafa vs pbo (19.2 months vs 11.7 months; HR [95% CI] 0.46 [0.26, 0.82]); median PFS by IRC, PET-CR rate, ORR, and median TTNT were also consistent with the overall 2L population (data will be presented). In the overall 2L pt subgroup, similar rates of TEAEs (100% vs 99%) were observed in the tafa vs pbo arm. Most common TEAEs in the tafa vs pbo arm were neutropenia (47% vs 39%), diarrhea (37% vs 31%), constipation (31% vs 30%), COVID-19 (30% vs 20%), rash (22% vs 24%), fatigue (20% vs 18%), cough (20% vs 17%), nausea (20% vs 14%), and muscle spasm (18% vs 20%). Grade 3 or 4 TEAEs were reported in 69% vs 61% of pts and serious TEAEs in 31% vs 25% of pts in the tafa and pbo arms, respectively. Three (2%) pts in both the tafa and pbo arms experienced fatal AEs. Conclusions: This analysis of R/R FL pts receiving 2L treatment in the inMIND study confirms that addition of tafa to len+R improved PFS, representing a 60% reduction in risk of progression or death, including in pts receiving prior anti-CD20+chemo or with POD24. Improvements were also observed in PET-CR, ORR, and TTNT. The safety profile was manageable in pts receiving 2L treatment with toxicities as expected for the pt population.