Modelling dose and schedule effects of AZD2811 nanoparticles targeting Aurora B kinase for treatment of diffuse large B-cell lymphoma

Barasertib (AZD1152), a pro-drug of the highly potent and selective Aurora B kinase inhibitor AZD2811, showed promising clinical activity in relapsed/refractory DLBCL patients administered as a 4-day infusion. To improve potential therapeutic benefit of Aurora B kinase inhibition, a nanoparticle formulation of AZD2811 has been developed to address limitations of repeated intravenous infusion. One of the challenges with the use of nanoparticles for chronic treatment of tumors is optimising dose and schedule required to enable repeat administration to sustain tumor growth inhibition. AZD2811 gives potent cell growth inhibition across a range of DLBCL cells lines i n vitro . In vivo , repeat administration of the AZD2811 nanoparticle gave anti-tumor activity at half the dose intensity of AZD1152. Compared to AZD1152, a single dose of AZD2811 nanoparticle gave less reduction in pHH3, but increased apoptosis and reduction of cells in G1 and G2/M, albeit it at later timepoints, suggesting that duration and depth of target inhibition influence the nature of the tumor cell response to drug. Further exploration of the influence of dose and schedule on efficacy revealed that AZD2811 nanoparticle can be used flexibly with repeat administration of 25 mg/kg administered up to 7 days apart being sufficient to maintain equivalent tumor control. Timing of repeat administration could be varied with 50mg/kg every 2 weeks controlling tumor control as effectively as 25mg/kg every week. AZD2811 nanoparticle can be administered with very different doses and schedules to inhibit DLBCL tumor growth, although maximal tumor growth inhibition was achieved with the highest dose intensities. Aurora B kinase inhibition as some cells can undergo rapid apoptosis with minimal polyploidy, and other persist with polyploid nuclei. Barasertib has shown promising benefits in phase 2 clinical trials in relapsed/refractory DLBCL patients, with an improvement of the overall response rate by approximately 20% (21). However, the inconvenience of the mode of administration as a 4-day infusion has prevented further exploration and development of barasertib. To address this challenge, a nanoparticle encapsulating AZD2811 has been developed (15). This study examines the pre-clinical activity of AZD2811 nanoparticle formulation in DLBCL cell lines and tumor models, and moreover how the nanoparticle can be delivered using different doses and schedules to achieve consistent anti-tumor activity. growth during the 6 days assay. Cells were exposed to an AZD2811 (AZD1152-hQPA) monotherapy dose response. Following 6 day compound incubation, cell viability was assessed through the addition of Alamar Blue reagent. The reaction was stopped with 0.5% SDS solution and fluorescence read on a Tecan Saffire II. The dose at which 50% inhibition of viability (IC50) was achieved was established for each cell line. For assessment of nuclear area, cells were stained with Hoescht (1:1000) in RPMI-1640, pipetting the cells up and down 3 times to disperse any clumps. After 20mins, the plates were centrifuged at 300g for 5min. 5 images per well at 20X magnification were taken for assessment of nuclear area. concentration profile of 4 cycles of the AZD2811 nanoparticle administrated at various doses in the subcutaneous OCI-LY19 xenograft model in CB17 SCID mice.