Rina Nishii

Significance Pharmacogenetics is a prototype of genomics-guided precision medicine. While there is a rapid expansion of novel pharmacogenetic variants discovered by genome sequencing, the lack of variant interpretation in a scalable fashion is a formidable barrier in this field. NUDT15 polymorphism is a major genetic cause for hematopoietic toxicity during thiopurine therapy. Motivated by the need to understand NUDT15 variant effects for clinical actions, we developed a massively parallel assay to preemptively characterize 91.8% of all possible missense variants in NUDT15 . Our function-based variant classification accurately predicted thiopurine toxicity risk alleles in patients. These results vastly improved the ability to implement genotype-guided thiopurine therapy and illustrated the value and potential of a high-throughput variant effect screen in general.

An unmet need exists for patients with relapsed/refractory (R/R) follicular lymphoma (FL) and high-risk disease features, such as progression of disease within 24 months (POD24) from first-line immunochemotherapy or disease refractory to both CD20-targeting agent and alkylator (double refractory), due to no established standard of care and poor outcomes. Chimeric antigen receptor (CAR) T cell therapy is an option in R/R FL after two or more lines of prior systemic therapy, but there is no consensus on its optimal timing in the disease course of FL, and there are no data in second-line (2L) treatment of patients with high-risk features. Lisocabtagene maraleucel (liso-cel) is an autologous, CD19-directed, 4-1BB CAR T cell product. The phase 2 TRANSCEND FL study evaluated liso-cel in patients with R/R FL, including 2L patients who all had POD24 from diagnosis after treatment with anti-CD20 antibody and alkylator ≤6 months of FL diagnosis and/or met modified Groupe d'Etude des Lymphomes Folliculaires criteria. Primary/key secondary endpoints were independent review committee-assessed overall response rate (ORR)/complete response (CR) rate. At data cutoff, 130 patients had received liso-cel (median follow-up, 18.9 months). Primary/key secondary endpoints were met. In third-line or later FL (n = 101), ORR was 97% (95% confidence interval (CI): 91.6‒99.4), and CR rate was 94% (95% CI: 87.5‒97.8). In 2L FL (n = 23), ORR was 96% (95% CI: 78.1‒99.9); all responders achieved CR. Cytokine release syndrome occurred in 58% of patients (grade ≥3, 1%); neurological events occurred in 15% of patients (grade ≥3, 2%). Liso-cel demonstrated efficacy and safety in patients with R/R FL, including high-risk 2L FL. ClinicalTrials.gov identifier: NCT04245839 .

Key Points We identified 3 novel loss-of-function variants in NUDT15 linked to thiopurine intolerance. Our findings extended the importance of NUDT15 variation in thiopurine pharmacogenetics in diverse populations.