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The antibody-drug conjugate polatuzumab vedotin (pola) has recently been approved in combination with bendamustine and rituximab (pola-BR) for patients with refractory or relapsed (r/r) large B-cell lymphoma (LBCL). To investigate the efficacy of pola-BR in a real-world setting, we retrospectively analyzed 105 patients with LBCL who were treated in 26 German centers under the national compassionate use program. Fifty-four patients received pola as a salvage treatment and 51 patients were treated with pola with the intention to bridge to chimeric antigen receptor (CAR) T-cell therapy (n = 41) or allogeneic hematopoietic cell transplantation (n = 10). Notably, patients in the salvage and bridging cohort had received a median of 3 prior treatment lines. In the salvage cohort, the best overall response rate was 48.1%. The 6-month progression-free survival and overall survival (OS) was 27.7% and 49.6%, respectively. In the bridging cohort, 51.2% of patients could be successfully bridged with pola to the intended CAR T-cell therapy. The combination of pola bridging and successful CAR T-cell therapy resulted in a 6-month OS of 77.9% calculated from pola initiation. Pola vedotin-rituximab without a chemotherapy backbone demonstrated encouraging overall response rates up to 40%, highlighting both an appropriate alternative for patients unsuitable for chemotherapy and a new treatment option for bridging before leukapheresis in patients intended for CAR T-cell therapy. Furthermore, 7 of 12 patients with previous failure of CAR T-cell therapy responded to a pola-containing regimen. These findings suggest that pola may serve as effective salvage and bridging treatment of r/r LBCL patients.
This post hoc analysis of a phase 3 trial explored the effect of pixantrone in patients (50 pixantrone, 47 comparator) with relapsed or refractory aggressive B-cell non-Hodgkin lymphoma (NHL) confirmed by centralized histological review. Patients received 28-d cycles of 85 mg/m2 pixantrone dimaleate (equivalent to 50 mg/m2 in the approved formulation) on days 1, 8 and 15, or comparator. The population was subdivided according to previous rituximab use and whether they received the study treatment as 3rd or 4th line. Median number of cycles was 4 (range, 2–6) with pixantrone and 3 (2–6) with comparator. In 3rd or 4th line, pixantrone was associated with higher complete response (CR) (23·1% vs. 5·1% comparator, P = 0·047) and overall response rate (ORR, 43·6% vs. 12·8%, P = 0·005). In 3rd or 4th line with previous rituximab (20 pixantrone, 18 comparator), pixantrone produced better ORR (45·0% vs. 11·1%, P = 0·033), CR (30·0% vs. 5·6%, P = 0·093) and progression-free survival (median 5·4 vs. 2·8 months, hazard ratio 0·52, 95% confidence interval 0·26–1·04) than the comparator. Similar results were found in patients without previous rituximab. There were no unexpected safety issues. Pixantrone monotherapy is more effective than comparator in relapsed or refractory aggressive B-cell NHL in the 3rd or 4th line setting, independently of previous rituximab.
Highlights
• Deletion of SPPL3 promotes resistance of malignant B cells to NK cell cytotoxicity
• Loss of SPPL3 blocks ligand binding to NK receptors via increased N-glycosylation
• B3GNT2 deletion reduces LacNAc addition and restores SPPL3-KO cell sensitivity to NK cells
• SPPL3-deficient cells are enriched in tetra-antennary N-glycans with LacNAc elongations
Summary
Natural killer (NK) cells are primary defenders against cancer precursors, but cancer cells can persist by evading immune surveillance. To investigate the genetic mechanisms underlying this evasion, we perform a genome-wide CRISPR screen using B lymphoblastoid cells. SPPL3, a peptidase that cleaves glycosyltransferases in the Golgi, emerges as a top hit facilitating evasion from NK cytotoxicity. SPPL3-deleted cells accumulate glycosyltransferases and complex N-glycans, disrupting not only binding of ligands to NK receptors but also binding of rituximab, a CD20 antibody approved for treating B cell cancers. Notably, inhibiting N-glycan maturation restores receptor binding and sensitivity to NK cells. A secondary CRISPR screen in SPPL3-deficient cells identifies B3GNT2, a transferase-mediating poly-LacNAc extension, as crucial for resistance. Mass spectrometry confirms enrichment of N-glycans bearing poly-LacNAc upon SPPL3 loss. Collectively, our study shows the essential role of SPPL3 and poly-LacNAc in cancer immune evasion, suggesting a promising target for cancer treatment.