Abstract 1716: Anticancer activity of the taxane nanoparticles, DEP® docetaxel and DEP® cabazitaxel
Authors: Kelly Brian D. , McLeod Victoria , Walker Rachael , Schreuders Jeannette , Jackson Susan , Giannis Michael , Dietinger Christine , Reitano Pauline , Pathak Rashmi , Xia Shirley , Cargill Anne , Seta Aynaz , Hufton Richard , Heery Graham , Cullinane Carleen , Owen David J. 
Published: September 2020

Docetaxel (Taxotere®) and cabazitaxel (Jevtana®) are mitotic inhibitors that function as effective cytotoxic agents and are widely used in many chemotherapy regimens. However, treatment with taxanes is limited by serious adverse toxicities, notably bone marrow toxicity (neutropenia, leukopenia and anemia) and hepatotoxicity. Taxanes are poorly water soluble and must be formulated with surfactants such as polysorbate, which can cause systemic adverse events (e.g. anaphylaxis and fluid retention) requiring predosing with corticosteroids. These combined drug and excipient toxicities limit clinical use and make them ideal candidates for improvement using dendrimer technology.

Starpharma's novel dendrimer nanoparticle DEP platform has broad applicability in drug delivery through improved drug solubility, efficacy and pharmacokinetics, reductions in certain toxicities (e.g. bone marrow toxicity) and generation of intellectual property. The DEP platform has shown reproducible benefits across a wide range of drug classes including small molecules, peptides and proteins. Currently there are three DEP candidates in the clinic; DEP docetaxel (DEP DTX), DEP cabazitaxel (DEP CTX), and DEP irinotecan. The fourth DEP candidate, AZD0466, is a promising Bcl-2/Bcl-xL inhibitor, partnered with AstraZeneca, and is currently transitioning into clinical trials in the US.

Starpharma's DEP DTX and DEP CTX are both PEGylated polylysine dendrimers with the drug conjugated to the surface via a hydrolytically labile linker. Both products have demonstrated superior efficacy and survival compared to the standard drug formulations in a range of xenograft cancer models in immunocompromised mice: breast (MDA-MB-2231), prostate (DU145), and pancreatic (CAPAN-1).

In the CAPAN-1 pancreatic xenograft model, the DEP taxanes were superior to Nab paclitaxel (Abraxane®) when dosed either as monotherapy or in combination with gemcitabine. Abraxane inhibited tumor growth by 85% (monotherapy) and 81% (combination with gemcitabine) compared to complete inhibition for DEP CTX and DEP DTX treated groups (at day 37). DEP CTX induced complete regression of tumors over the duration of the study. Treatment with DEP taxanes significantly extended survival compared to Abraxane as monotherapy (P= 0.004, DEP DTX; P &lt;0.0001, DEP CTX), and in combination with gemcitabine (P&lt;0.0001, DEP DTX; P&lt;0.0001, DEP CTX).

In summary, both DEP taxanes are well tolerated and show significant efficacy and survival benefits compared to current standard of care therapies when used either as a monotherapy or in combination. DEP CTX and DEP DTX are two of four clinical stage products from Starpharma's DEP platform. DEP DTX is currently in a P2 clinical trial at Guy's and St Thomas', NUTH, The Leeds Teaching Hospital, UCLH, The Christies and The Beatson while DEP CTX is in a phase 1/2 adaptive trial at Guy's and St Thomas', UCLH, Velindre Cancer Centre and ICLH.

Citation Format: Brian D. Kelly, Victoria McLeod, Rachael Walker, Jeannette Schreuders, Susan Jackson, Michael Giannis, Christine Dietinger, Pauline Reitano, Rashmi Pathak, Shirley Xia, Anne Cargill, Aynaz Seta, Richard Hufton, Graham Heery, Carleen Cullinane, David J. Owen. Anticancer activity of the taxane nanoparticles, DEP® docetaxel and DEP® cabazitaxel [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1716.