Keto-Functionalized Polymer Scaffolds As Versatile Precursors to Polymer Side Chain Conjugates.

A new methacrylate monomer with a reactive ketone side-chain, 2-(4-oxo-pentanoate) ethyl methacrylate (PAEMA), was synthesized and subsequently polymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization to give a polymer with a narrow molecular weight distribution (PDI = 1.25). The polymer was chain extended with poly(ethylene glycol methyl ether acrylate) (PEGMA) to yield a block copolymer. Aminooxy containing small molecules and oligoethylene glycol were conjugated to the ketone functionality of the side chain in high yields. Cytotoxicity of the oxime-linked tetra(ethylene glycol) polymer to mouse fibroblast cells was investigated; the polymer was found to be non-cytotoxic up to 1 mg/mL. The ease with which this polymer is functionalized, suggests that it may be useful in forming tailored polymeric medicines.

Phase I evaluation of gemcitabine, mitoxantrone, and their effect on plasma disposition of fludarabine in patients with relapsed or refractory acute myeloid leukemia.

Our aim was to estimate the duration of maximum tolerated dose (MTD) duration for gemcitabine given as a continuous infusion in combination with fludarabine and mitoxantrone and to evaluate potential pharmacokinetic (PK) interactions in 17 patients with refractory or relapsed acute myeloid leukaemia (AML). Gemcitabine was administered at 10 mg/m(2)/min for 3-15 h, fludarabine at 25 mg/m(2) daily for days 1-5 and mitoxantrone at 10 mg/m(2) daily on days 1-3. PK studies revealed that fludarabine clearance was not affected by gemcitabine but mean terminal half-life and volume of distribution of fludarabine were slightly increased. The duration of MTD for gemcitabine was 12 h. Our previous in vitro work has demonstrated the binary combination of gemcitabine + fludarabine is most synergistic at a molar ratio around 0.002. However, with MTD dosing this drug ratio is not optimal to produce synergy and future studies using ratiometric dosing are required to confirm these findings.

Low-dose weekly paclitaxel for recurrent or refractory aggressive non-Hodgkin lymphoma.

BACKGROUND: Many patients with recurrent, intermediate or high-grade non-Hodgkin lymphoma (NHL) may not respond to or are not candidates for aggressive salvage chemotherapy. Effective, less toxic regimens are needed. Although high-dose taxanes have not been reported to be very effective for the treatment of lymphoma, different delivery rates may allow for different mechanisms of action to be manifest and result in a different toxicity profile and response rate. The current study tested this hypothesis by using low-dose, weekly paclitaxel in patients with recurrent or refractory NHL. METHODS: Adults age > 18 years with refractory or recurrent, aggressive NHL who were not considered curable with standard high-dose therapy received paclitaxel at a dose of 80 mg/m2 weekly for 5 weeks for 2 cycles. RESULTS: Thirty-four patients with refractory NHL and 4 patients with recurrent disease were treated. Approximately 45% of the patients had achieved a prior disease remission. The median number of prior regimens received was 3, 74% of the patients had an International Prognostic Index of > or = 3 at the time of study entry, and 29% had failed high-dose therapy with autologous hematopoietic support. Only one patient encountered severe toxicity (sepsis). Myelosuppression was reported to occur in approximately 20% of patients. A total of 10 patients (26%) achieved a complete disease response and 4 patients (11%) achieved a partial response. CONCLUSIONS: In the current study, low-dose, weekly paclitaxel therapy was found to provide a well tolerated and less toxic approach to the treatment of refractory NHL, with encouraging responses noted in heavily pretreated patients. However, evaluation in patients with an earlier stage of disease is warranted.