Purpose: KML-001 (sodium metaarsenite) displaces hTERT from the nucleus and is synergistic with cisplatin. This phase I trial tested the tolerability, activity and pharmacology of this combination.
Methods: Patients with advanced solid tumors that were "platinum sensitive," PS 0-1, normal renal and hepatic function were eligible. Treatment was with cisplatin 75 mg/m2 day 1 and KML-001 p.o. daily days 1-14 on a 21-day cycle. A standard 3 + 3 design was employed. Blood specimens for arsenic and platinum pharmacokinetics were obtained at 0, 1, 2, 3, 4, 5, 6, 24 h and days 8, 15 and 22.
Results: Eighteen patients (7 M, 11 F) were evaluable for the primary endpoint of toxicity. Patients were heavily pretreated for a variety of malignancies (mean number of prior regimens = 3). Sixteen had prior platinum therapy. The dose-limiting toxicity was prolongation of the QTc interval, seen in three patients in cohort 3 (20 mg) (two during cycle 1, one during cycle 2). A documented response was seen in a patient with heavily pretreated SCLC in cohort one. Several other patients had reduction in tumor burden. In addition to the dose-limiting toxicity of QTc prolongation, the most common toxicities observed were nausea and vomiting and cytopenias. Myelosuppression was primarily seen in patients who had undergone prior radiotherapy.
Conclusions: The combination of KML-001 and cisplatin was technically feasible and active. However, the occurrence of significant QTc prolongation led to discontinuation of the trial. This prolongation was likely a result of electrolyte abnormalities resulting from cisplatin superimposed on the known risks of arsenicals and QTc prolongation. Combinations with other platinum agents (e.g., carboplatin) should be considered. This is the first fully reported human trial of KML-001.
Keywords: Arsenical; KML-001; Phase 1; Telomere.