Purpose: Pyrazoloacridine (PZA) is an investigational nucleic acid binding agent that inhibits the activity of topoisomerases I and II through a mechanism distinct from other topoisomerase poisons. PZA shows schedule-independent cytotoxicity against tumor cells, whereas host toxicity is greater with shorter infusions. We assessed the clinical toxicities and pharmacologic effects of PZA given as a 24-h i.v. infusion weekly for 3 of 4 weeks. Experimental Design: Thirty-two adult patients with solid tumors received PZA at five dose levels (100-351 mg/m2). Plasma samples were obtained at the end of the PZA infusion at all of the dose levels, with extended sampling in a cohort treated at the recommended dose. Results: Dose-limiting granulocytopenia and mucositis occurred in 2 of 6 patients at 351 mg/m2, but lower doses were well tolerated. No responses were seen, but 28% had stable disease for ≥3 months. Plasma levels strongly correlated with the degree of granulocytopenia. Extended pharmacokinetics in 7 patients treated with 281 mg/m2 indicated the following averages: maximum plasma level, 1.6 μM; area under the plasma concentration-time curve, 56 μM-h; terminal half-life, 27 h; urinary recovery, 17% over 72 h. DNA fragmentation in post-PZA bone marrow mononuclear cells was seen in 9 of 28 samples (all at ≥281 mg/m2). Conclusions: Unlike other schedules of PZA, neurotoxicity and thrombocytopenia were not problematic with a weekly 24-h infusion of PZA. The recommended Phase II dose is 281 mg/m2, which was well tolerated. Both end of infusion plasma levels and presence of DNA damage correlated with granulocyte toxicity.
|Original language||English (US)|
|Number of pages||8|
|Journal||Clinical Cancer Research|
|State||Published - 2002|
ASJC Scopus subject areas
- Cancer Research