onametostat (JNJ-64619178)

Analysis of consensus QSAR models identified two highly active PRMT5 inhibitor candidates (CHEMBL4539612 and CHEMBL4577464), with high affinity for binding (- 13.5 to - 13.7 kcal/mol) to the PRMT5 active site and interactions similar to those of the known clinical PRMT5 inhibitor ONAMETOSTAT...Network pharmacology analysis indicated that PRMT5 and its interacting partners are mainly associated with histone arginine methylation and spliceosomal assembly, processes that are frequently dysregulated in MTAP-deficient cancers. These findings suggest CHEMBL4539612 and CHEMBL4577464 as promising scaffolds for the development of selective PRMT5 inhibitors in epigenetic cancer therapy.

P1, N=114, Completed, Janssen Research & Development, LLC | Active, not recruiting --> Completed | Trial completion date: Dec 2025 --> Sep 2025 | Trial primary completion date: Dec 2025 --> Sep 2025

P1, N=80, Enrolling by invitation, Janssen Research & Development, LLC

P1, N=114, Active, not recruiting, Janssen Research & Development, LLC | Trial completion date: Dec 2024 --> Dec 2025 | Trial primary completion date: Dec 2024 --> Dec 2025

Indeed, the PRMT5 inhibitor, JNJ-64619178, reduced cell viability and SNRPD3 methylation in neuroblastoma cells with high SNRPD3 and MYCN expression...Third, this leads to balanced alterative splicing (AS) activitiy that is favorable to neuroblastoma. Together this forms as a therapeutic vulnerability where SNRPD3 perturbation or PRMT5 inhibitors are selectively toxic to neuroblastoma by conditionally disturbing splicing activity.

A tolerable dose of JNJ-64619178 was identified in patients with LR MDS. However, no evidence of clinical benefit was observed.

P1, N=114, Active, not recruiting, Janssen Research & Development, LLC | Trial completion date: Dec 2023 --> Dec 2024 | Trial primary completion date: Dec 2023 --> Dec 2024

JNJ-64619178 demonstrated manageable dose-dependent toxicity and preliminary evidence of antitumor activity in ACC and other tumor types. Plasma exposure was dose dependent, and target inhibition was maintained with intermittent and continuous dosing. Based on safety, clinical activity, PK, and PD findings, two provisional RP2Ds were selected: 1.5 mg intermittently and 1.0 mg once daily. Aside from ACC, clinical benefit was limited, and biomarkers to enrich for responsiveness to PRMT5 inhibition will be needed for further development.

It targets NED induced by FIR in prostate cancer cells. JNJ-64619178 can radiosensitize and suppress NED induced by FIR in prostate cancer cells and can be a potential radiosensitizer for prostate cancer treatment.

We validated the synergistic effects and mechanisms of combined treatment with a type I PRMT inhibitor and a PRMT5 inhibitor (JNJ-64619178, GSK3326595/EPZ015938 or an in-house PRMT5i) using cell-based assays and in vivo studies...In vitro and in vivo studies revealed that inhibitors of type I PRMT and MAT2A (AG-270) dosing combination indeed exhibited stronger anti-cancer activity than mono-treatment...In vivo, the combination of type I PRMT inhibitor with different FLT3 inhibitors (Gilteritinib, Midostaurin, or CTS2016) led to deeper antitumor responses in a variety of FLT3-ITD AML models. Taken together, these findings support the co-administration of type I PRMT inhibitor with various therapies including epigenetic reprogramming, cancer metabolism modulation, or targeted therapies for receptor tyrosine kinases, which could benefit cancer patients as a promising therapeutic strategy.