Search

Amonafide is extensively metabolized, including conversion by N-acetylation to an active metabolite. Our previous studies have shown that fast acetylators of amonafide have increased toxicity, and we have recommended doses of 250 and 375 mg m-2 day-1 for 5 days, for fast and slow acetylators, respectively. Despite phenotype-specific dosing, significant variability in leukopenia persisted. The goal of this study was to construct and validate a pharmacodynamic model-based dosing strategy for amonafide, to try to further decrease inter-patient variability in leukopenia. The model was based on a training data set of 41 patients previously treated with amonafide. The first cycle nadir WBC was modelled as a function of dose, acetylator phenotype and baseline patient factors. This model was validated prospectively on patients similar to those in our previous studies. Based on the training data set, the optimal model was defined by three factors: acetylator phenotype, gender, and pretreatment WBC. Using this model and a target WBC nadir of 1700 microliters-1, six dosing strata were prospectively evaluated. A total of 24 fast acetylators received either 238 or 276 mg m-2 day-1 and 20 slow acetylators received between 345 and 485 mg m-2 day-1. The mean (+/- SE) error (deviation from target nadir) was 430 (+/- 240) cells microliters-1. Submaximal treatment (yielding grade 0-1 leukopenia) was limited to 20% of patients, while 55% experienced grade 2-3 toxicity. A complex dosing strategy for amonafide is feasible, employing prospective acetylator phenotyping, model-guided dosing, and adaptive control.

Background: Patients with advanced or metastatic cancer treated in Phase I clinical trials are considered to have a poor prognosis. Survival from first treatment in a Phase I trial was determined for 349 patients. Univariate and multivariate survival analyses were performed to determine whether potential prognostic factors and distinct risk groups could be identified., Methods: Patients were identified retrospectively from a large data base of patients with advanced or metastatic cancer treated in Phase I clinical trials at the University of Chicago between February 1987 and October 1991., Results: With a median follow-up of 29 months, 10% of patients were alive at the time of analysis. Twenty-nine percent were alive 1 year after the initiation of Phase I chemotherapy, and the median survival from first treatment in a Phase I study was 6.5 months. Multivariate analysis indicated that a better pretreatment performance status, a higher pretreatment serum albumin concentration, a lower pretreatment platelet count, no prior cisplatin chemotherapy, and a genitourinary or gynecologic cancer diagnosis were predictive of better survival. Three risk groups incorporating these five variables were identified, with median survivals of 12.7, 7.4, and 3.5 months for the good, intermediate, and poor risk groups, respectively., Conclusion: Patients treated in Phase I clinical trials have a median survival of 6.5 months, even though some patients have been treated at early (subtoxic and potentially subtherapeutic) dose levels. The results of this study may allow the identification of patients who are likely to survive long enough to contribute information on acute and cumulative drug-related toxicities and, possibly, tumor response.