On November 10, 2015 Celator Pharmaceuticals, Inc. (Nasdaq: CPXX) reported the presentation of positive results from its CombiPlex technology platform applied to drug combinations incorporating molecularly targeted agents (MTAs) at the AACR (Free AACR Whitepaper)-NCI-EORTC AACR-NCI-EORTC (Free AACR-NCI-EORTC Whitepaper) International Conference on Molecular Targets and Cancer Therapeutics (EORTC-NCI-AACR) (Free ASGCT Whitepaper) (Free EORTC-NCI-AACR Whitepaper) (Press release, Celator Pharmaceuticals, NOV 10, 2015, View Source [SID:1234508179]).

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CombiPlex is Celator’s proprietary technology that uses nano-scale drug carriers to ensure the optimal ratio of anticancer drugs are simultaneously delivered and selectively exposed to tumor cells for prolonged periods of time while reducing drug exposure and toxicity to normal tissues. The technology addresses difficulties often experienced with conventional MTA combination regimens, where significant toxicities and/or incomplete target inhibition can lead to sub-optimal patient outcomes.

Pre-clinical data presented at the conference demonstrated the broad applicability of Celator’s hydrophobic prodrug nanoparticle (HPN) delivery technology to MTAs from diverse classes, including inhibitors of MEK, Akt, HSP90, B-Raf and FGFR. In all cases, Celator’s proprietary HPN delivery eliminated the early drug distribution phase observed for conventional formulations of these agents, which historically has been associated with significant exposure and toxicity to normal tissues. In fact, HPN co-formulated combinations of docetaxel plus the HSP90 inhibitor AUY922, and the MEK:Akt inhibitor combination of selumetinib plus ipatasertib, could be administered at much higher drug exposure with maintained improvements in safety while also resulting in increased efficacy.

The largest improvements were observed in tumor models known to be more resistant to conventional dosing forms of the two combinations. Optimal efficacy was achieved at drug ratios of 1:2 and 2:1, respectively. In the case of docetaxel:AUY922, the conventional formulation provided negligible tumor growth delay at the maximum tolerated dose (MTD) in the OVCAR-8 human ovarian xenograft model with tumors reaching 1 gram in size in approximately 25 days. In contrast, dosing with Celator’s proprietary HPN formulation at MTD, tumors grew to only half that size after 50 days demonstrating potent tumor growth inhibition.

"As an oncologist who has personally experienced the challenges with combining conventional formulations of molecularly targeted agents in a clinical setting, I am very encouraged by the results Celator has generated using its CombiPlex technology," said Dr. Tony Tolcher, director of clinical research at South Texas Accelerated Research Therapeutics. "This approach could provide an important breakthrough in our ability to optimize the therapeutic index and patient outcomes for many molecularly targeted agent combinations."

Once HPN formulation conditions were optimized for these initial combinations, the approach was readily extended to the B-Raf inhibitor GDC0879 and the FGFR inhibitor LY2874455 and both were successfully co-formulated with the MEK inhibitor selumetinib resulting in coordinated drug exposure in the plasma. In addition, the drug components could be "mixed and matched," and this versatility was then taken one step further by generating a 3-drug combination, co-formulating selumetinib, AUY922 and docetaxel into a single HPN that exhibited a plasma half-life in the range of 10 hours in mice with no early distribution phase.

"The CombiPlex technology platform continues to deliver on its promise to optimize the efficacy of a wide range of anticancer drug combinations," said Dr. Lawrence Mayer, president and chief scientific officer at Celator. "The successful application of this technology to molecularly targeted agents across a wide range of drug classes makes a compelling data package that we believe will be instrumental in attracting R&D collaborations with pharmaceutical companies."