Background Hyaluronan (HA) is a ligand for the CD44 receptor which is crucial to cancer cell proliferation and metastasis. High levels of CD44 expression in many cancers have encouraged the development of HA-based carriers for anti-cancer therapeutics. Purpose The objective of this study was to determine whether HA conjugation of anticancer drugs impacts CD44-specific HA-drug uptake and disposition by human head and neck cancer cells. Methods The internalization and cellular disposition of hyaluronan-doxorubicin (HA-DOX), hyaluronan-cisplatin (HA-Pt), and hyaluronan-cyanine7 (HA-Cy7) conjugates were investigated by inhibiting endocytosis pathways, and by inhibiting the CD44–mediated internalization pathways that are known to mediate hyaluronan uptake in vitro. Results Cellular internalization of HA was regulated by CD44 receptors. In mouse xenografts, HA conjugation significantly enhanced tumor cell uptake compared to unconjugated drug. Discussion The results suggested that the main mechanism of HA-based conjugate uptake may be active transport via CD44 in conjunction with a clathrin–dependent endocytic pathway. Other HA receptors, hyaluronan–mediated motility receptor (RHAMM) and lymphatic vessel endothelial hyaluronan receptor (LYVE-1), did not play a significant role in conjugate uptake. Conclusions HA conjugation significantly increased CD44 mediated drug uptake and extended the residence time of drugs in tumor cells.

Purpose To determine aerosol administration capability and therapeutic efficacy of the new formulation of hyaluronan cisplatin conjugates, HylaPlat™ (HA-Pt), for lung cancer treatment. Methods In vitro formulation stability test, 2D and 3D spheroid cell culture and in vivo efficacy studies using mouse orthotopic allograft models were conducted. Results The HA-Pt effectively attenuated cell growth in 2D and 3D cultures with IC50 of 2.62 and 5.36 μM, respectively, which were comparable to those with unconjugated control cisplatin-dependent growth inhibition (IC50 1.64 and 4.63 μM, respectively). A single dose of either 7.5 or 15 mg/kg HA-Pt (cisplatin equivalent) by intratracheal aerosol spray seven days after Lewis lung carcinoma (LLC) cell inoculation markedly inhibited growth of LLC allografts in mouse lungs and resulted in a 90 or 94% reduction of tumor nodule numbers, respectively, as compared to those from the PBS control. Cancer stem cells and cisplatin resistant cells marker, CD44 expression decreased in the tumor nodules of the HA-Pt but not in those of cisplatin treated groups. Conclusions The current study suggests that an intratracheal aerosol administration of the HA-Pt nanoparticles offers an effective strategy for lung cancer treatment and this treatment may induce only limited cisplatin resistance.

Objective To conduct an open label, multi-dose Phase I/II clinical study in spontaneous canine cancers and evaluate the pharmacokinetics, safety, and efficacy of the hyaluronan-based cisplatin formulation (HA-Pt). Animals 13 dogs with heterogeneous, naturally occurring cancers. Procedures The dogs received up to four injections of 10-30 mg/m2 HA-Pt into the tumor or peritumoral sub-mucosa at three-week intervals. Blood sample (2 mL) was collected from the jugular catheter at 0.5, 1, 2, 4, and 24 hours following drug administration. A complete blood count and renal profile with urinalysis were conducted prior to and one week after each treatment. Tumor measurements were collected three weeks following each administration to assess response. Results Of the 13 dogs with heterogeneous, naturally occurring cancers, 23% had complete response and 15% had partial response or stable disease. Among the dogs that received drug with low diaquated content, the complete response rate for SCC was 3/7 (43%). Myelosuppression and cardiac toxicity were observed for 38% and 19% of the dogs, respectively. The formulation did not cause nephrotoxicity, the dose-limiting toxicity of standard cisplatin, in any dogs. Conclusions and Clinical Relevance The HA-Pt formulation demonstrated positive response in spontaneous canine squamous cell carcinomas. It did not cause nephrotoxicity in any patients. Canine oral SCC is very homogenous in progression and drug response to human HNSCC, and these results could be useful in developing human treatments.

Cisplatin, a platinum chemotherapeutic, is one of the most commonly used chemotherapeutic agents for many solid tumors. In this work, we developed and validated an inductively coupled plasma mass spectrometry (ICP-MS) method for quantitative determination of platinum levels in rat urine, plasma, and tissue matrices including liver, brain, lungs, kidney, muscle, heart, spleen, bladder, and lymph nodes. The tissues were processed using a microwave accelerated reaction system (MARS) system prior to analysis on an Agilent 7500 ICP-MS. According to the Food and Drug Administration guidance for industry, bioanalytical validation parameters of the method, such as selectivity, accuracy, precision, recovery, and stability were evaluated in rat biological samples. Our data suggested that the method was selective for platinum without interferences caused by other presenting elements, and the lower limit of quantification was 0.5 ppb. The accuracy and precision of the method were within 15% variation and the recoveries of platinum for all tissue matrices examined were determined to be 85–115% of the theoretical values. The stability of the platinum-containing solutions, including calibration standards, stock solutions, and processed samples in rat biological matrices was investigated. Results indicated that the samples were stable after three cycles of freeze–thaw and for up to three months.

The purpose of this study was to develop a safe and efficacious drug delivery platform for sustained release of cisplatin after locoregional administration. We successfully synthesized hyaluronan-cisplatin nanoconjugates (HA-Lys-Pt) using an N-Ac-lysine linker, which formed a thermodynamically stable 5-membered ring with the platinum. The conjugate was characterized for release kinetics, in vitro anti-proliferative activity, degradability, impurity content, formation of Pt-DNA adducts, pharmacokinetics, tolerability in rodents and canines, and for efficacy in rodents. The 75kD HA-Lys-Pt (75HALys-Pt) sustained release of platinum with a 69 hour half-life in phosphate buffered saline without substantial burst release. Compared to intravenous cisplatin, subcutaneously injected 75HA-Lys-Pt formed 3.2-fold more Pt-DNA adducts in rat peripheral blood mononuclear cells compared to intravenous cisplatin over 96 hours. Subcutaneous 75HA-Lys-Pt was tolerable in rats at 40 mg/kg (4× the LD50 of conventional cisplatin) and resulted in 62.5% partial response and 37.5% stable disease in murine xenografts of head and neck squamous cell cancer (20 mg/kg/wk × 3 wk). 75HA-Lys-Pt demonstrated extended tmax and improved area-under-the-curve compared to cisplatin in rats and canines. Canine safety was demonstrated by liver enzyme and electrolyte levels, complete blood count, and urinalysis.