NSD2 inhibitors rewire chromatin to treat lung and pancreatic cancers.

NSD2 catalyses the epigenetic modification H3K36me2 (refs. 1,2) and is a candidate convergent downstream effector of oncogenic signalling in diverse malignancies3-5. However, it remains unclear whether the enzymatic activity of NSD2 is therapeutically targetable. Here we characterize a series of clinical-grade small-molecule catalytic NSD2 inhibitors (NSD2i) and show that the pharmacological targeting of NSD2 constitutes an epigenetic dependency with broad therapeutic efficacy in KRAS-driven preclinical cancer models. NSD2i inhibits NSD2 with single-digit nanomolar half-maximal inhibitory concentration potency and high selectivity over related methyltransferases. Structural analyses reveal that the specificity of NSD2i for NSD2 is due to competitive binding with S-adenosylmethionine and catalytic disruption through a binary-channel obstruction mechanism. Proteo-epigenomic and single-cell strategies in pancreatic and lung cancer models support a mechanism in which sustained NSD2i exposure reverses pathological H3K36me2-driven chromatin plasticity, re-establishing silencing at H3K27me3-legacy loci to curtail oncogenic gene expression programs. Accordingly, NSD2i impairs the viability of pancreatic and lung cancer cells and the growth of patient-derived xenograft tumours. Furthermore, NSD2i, which is well-tolerated in vivo, prolongs survival in advanced-stage autochthonous KRASG12C-driven pancreatic and lung tumours in mouse models to a comparable level as KRAS inhibition with sotorasib6. In these models, treatment with both a NSD2 inhibitor and sotorasib synergize to confer sustained survival with extensive tumour regression and elimination. Together, our work uncovers targeting of the NSD2-H3K36me2 axis as an actionable vulnerability in difficult to treat cancers and provides support for the evaluation of NSD2 and KRAS inhibitor combination therapies in a clinical setting.