MOBILIZED PERIPHERAL-BLOOD PROGENITOR CELLS (PBPC) IN SUPPORT OF TANDEM CYCLES OF HIGH-DOSE CHEMOTHERAPY (HDC)

We evaluated the efficacy, toxicity and feasibility of two cycles of h igh-dose chemotherapy (HDC), each supported with mobilized peripheral blood progenitor cells (PBPC). Ninety-six patients with metastatic or high-risk cancers received disease-specific HDC regimens, The first cy cle consisted of cyclophosphamide 6000 mg/m(2), thiotepa 500 mg/m(2) a nd carboplatin 1200 mg/m(2), Alternatively, some patients received eto poside 1800 mg/m(2) substituted for thiotepa, A second cycle was plann ed 6-8 weeks later and consisted of mitoxantrone 60 mg/m(2) with eithe r melphalan 140 mg/m(2) or thiotepa 600 mg/m(2), PBPC were mobilized w ith either growth factor alone or cyclophosphamide followed by growth factor(s), Thirty-four of 96 enrolled patients (35%) did not receive t he second cycle. The reasons were: patient refusal (15); insurance ref usal (three); toxicities of cycle 1 (seven); no response to cycle 1 (f our); and inadequate mobilization or poor engraftment, (five), Of the 33 patients who entered cycle 2 with measurable disease, 28 demonstrat ed further response after cycle 2 (including 10 who entered CR), One p atient died of toxicity after each cycle, Hematologic recovery was rap id and complete in most patients, Tandem cycles of high-dose chemother apy supported by PBPC are feasible and safe, although many patients fa il to receive the second treatment, Preliminary evaluation shows evide nce of further antitumor efficacy following cycle 2.