Purpose: N-Benzoyl staurosporine (PKC412) is a protein kinase C inhibitor with antitumor activity in laboratory models. We determined the toxicity of oral PKC412 administered daily for repeat cycles of 28 days. Patients and Methods: Thirty-two patients with advanced solid cancers were treated at seven dose levels (12.5 to 300 mg daily) for a total of 68 cycles. Results: The most frequent treatment-related toxicities were nausea, vomiting, fatigue, and diarrhea. At the two top dose levels (225 and 300 mg/d), 15 of 16 patients experienced nausea/vomiting (common toxicity criteria [CTC], version 1), grade 2 in nine of 16 and grade 3 in three of 16 patients; and six of 16 patients developed CTC grade 2 diarrhea. After 1 month of treatment, there were significant reductions in circulating lymphocyte (P <.02) and monocyte (P <.01) counts in patients receiving doses ≥ 100 mg/d. Nevertheless, only two patients developed myelosuppression (both grade 2). Of two patients with progressive cholangio-carcinoma, one attained stable disease lasting 4.5 months and one a partial response lasting 4 months. There was o linear relationship between PKC412 dose and area under the curve0-24 hours and maximum plasma concentration with marked interpatient variability. The estimated median elimination half-life was 1.6 days (range, 0.9 to 4.0 days), and a metabolite with a median half-life of 36 days was detected. Steady-state PKC412 plasma levels at the top three dose cohorts (150 to 300 mg) were five to 10 limes the cellular 50% inhibitory concentration for PKC412 of 0.2 to 0.7 μmol/L. Conclusion: PKC412 con be safely administered by chronic oral therapy, and 150 mg/d is suitable for phase II studies. The pharmacokinetics and lack of conventional toxicity indicate that pharmacodynamic measures may be additionally needed to optimize the drug dose and schedule.
|Number of pages||8|
|Journal||Journal of Clinical Oncology|
|Publication status||Published - Mar 1 2001|
ASJC Scopus subject areas
- Cancer Research