TNFRSF17 deletion

Patient 3 received 3 sequential therapies with Ide-cel (DOR = 3 mos), teclistamab (DOR = 6 mos), and then talquetamab with daratumumab with an ongoing response of 11 mos...Patient 5 with penta-refractory disease and high disease burden (> 90% BM infiltration) had no response to elranatamab, however achieved an ongoing sCR (DOR = 30 mos) with talquetamab, daratumumab and pomalidomide (Tal-DP)...Therefore, TCE resistance derived from BCMA mutations does not preclude retreatment with another anti-BCMA TCE or CAR T. We here describe variable non-overlapping mechanisms mediating resistance to sequential TCE and CAR T therapies. Dynamic surveillance for antigenic escape and functional evaluation of T cell fitness will optimize immunotherapy sequencing.

Our findings highlight the impact of sBCMA levels and its chronicity of exposure on anti-BCMA TCE and CAR T activities in MM. We further identified structural genomic events driving TNFRSF17 over-expression and their correlation to sBCMA levels facilitating tumoral immunotherapeutic escape.

Patient 3 received 3 sequential therapies with Ide-cel (DOR = 3 mos), teclistamab (DOR = 6 mos), and then talquetamab with daratumumab with an ongoing response of 11 mos...Patient 5 with penta-refractory disease and high disease burden (> 90% BM infiltration) had no response to elranatamab, however achieved an ongoing sCR (DOR = 30 mos) with talquetamab, daratumumab and pomalidomide (Tal-DP)...Therefore, TCE resistance derived from BCMA mutations does not preclude retreatment with another anti-BCMA TCE or CAR T. We here describe variable non-overlapping mechanisms mediating resistance to sequential TCE and CAR T therapies. Dynamic surveillance for antigenic escape and functional evaluation of T cell fitness will optimize immunotherapy sequencing.

We identified selection of a clone with homozygous deletion of TNFRSF17 (BCMA) as the underlying mechanism of immune escape. Furthermore, we found heterozygous TNFRSF17 loss or monosomy 16 in 37 out of 168 patients with MM, including 28 out of 33 patients with hyperhaploid MM who had not been previously treated with BCMA-targeting therapies, suggesting that heterozygous TNFRSF17 deletion at baseline could theoretically be a risk factor for BCMA loss after immunotherapy.