2586 Background: PNT2258 contains PNT100, a DNA interference (DNAi) oligonucleotide encapsulated in a lipid nanoparticle. PNT2258 targets the BCL2 gene and is undergoing evaluation in patients with r/r NHL (NCT01733238). PNT2258 exhibits single-agent anti-tumor effect (50% ORR) in patients with r/r follicular or diffuse large B-cell lymphoma. The study also evaluated pharmacokinetic (PK) parameters in this target population, as reported here. Methods: Patients received 120 mg/m2of PNT2258 IV on days 1-5 of a 21-day cycle. The concentrations of PNT2258 (measured as total PNT100) were determined pre-infusion and at 30, 60, 90, 120 and 150 minutes and at 24 hours by a validated hybridization-ligation bioanalytical method that measured PNT100 content using a complementary template probe followed by visualization by ELISA. Results: No free PNT100 was found in the plasma samples and detergent solubilization of intact PNT2258 in plasma was required to release encapsulated PNT100, indicating the stability of the ...