Ifosfamide tolerance in osteosarcoma patients previously treated with cis-diamminedichloroplatinum-II: renal, hematologic, and neurologic observations.

We attempted to ascertain renal, hematologic, and neurologic tolerance to ifosfamide (IFX) in pediatric patients previously treated with large single and cumulative doses of cis-Diamminedichloroplatinum-II (CDP) for osteosarcoma (OS). Twenty OS patients were treated with CDP: initially 150 mg/m2 was administered every 2 weeks for a maximum of seven courses. Later, other agents, including additional CDP, were also administered. Twelve patients were treated with intra-arterial CDP, one with intra-arterial, and later intravenous CDP, and seven with intravenous CDP. Patients who relapsed were treated with IFX. Renal function was monitored by measuring creatinine clearance, serum electrolytes, total protein, albumin and CO2 content, and urine analysis during IFX therapy. Prior to initiation of IFX, creatinine clearance was above 60 ml/min/m2 in all except one patient who had developed a hemolytic uremic syndrome (HUS). Cumulative CDP doses ranged from 300 to 22,500 mg/m2, and cumulative IFX doses 12 to 128 gm/m2. Myelosuppression was monitored by obtaining routine hemograms midway between each course of treatment. Neurologic tolerance was assessed by reviewing the medical records for any abnormality. The interval between CDP and IFX ranged from 1 to 64 months. All patients experienced a progressive reduction in creatinine clearance with CDP. The reduction in creatinine clearance, measured from base-line after three to four courses varied from 10 to 53.7%, after four to seven courses from 19 to 78%, and after seven courses from 12 to 80.5%. In all patients except five, including the HUS patient, creatinine clearance remained above 60 ml/min/m2 during IFX therapy. Twelve patients developed hypo-magnesemia in the vicinity of 1.4 to 1.6 mg/dl during CDP treatment and required magnesium supplementation. They were asymptomatic and the abnormality did not affect IFX tolerance. Fourteen patients intermittently displayed variable degrees of glycosuria, phosphaturia, and/or proteinuria during IFX therapy. This was considered to be a forma frustre type of Fanconi's syndrome. Approximately 80% of courses of IFX were associated with reversible myelosuppression. No neurologic abnormalities were detected. The abnormalities detected during IFX treatment were not major, did not give rise to symptomatology, and did not require discontinuation of therapy. Renal abnormalities were considered a forma frustre type of Fanconi's syndrome. Provided a creatinine clearance of 60 ml/min/m2 is accepted as a prerequisite for treatment, and no major preexisting renal disease is present, IFX is well tolerated by most patients previously exposed to very high cumulative doses of CDP.