Busulfan (Bu) is commonly used as a component of conditioning regimens for hematopoietic stem cell transplantation. Precise delivery of the oral formulation is compromised by erratic gastrointestinal absorption. An IV Bu formulation was developed to provide dose assurance and complete bioavailability. In a phase I study, the plasma bioequivalence of IV Bu was established at approximately 80% of the oral dose. We now report the findings of the first phase II study, in which 61 adults with hematologic cancers were treated with a Bu-cyclophosphamide (BuCy) regimen consisting of IV Bu (0.8 mg/kg every 6 hours x 16) followed by Cy (60 mg/kg qd x 2) and transplantation of stem cells from an HLA-matched sibling donor. The median age of study participants was 37 years; 75% of patients had active disease; 48% were heavily pretreated, and 13% had undergone a prior transplantation. Median follow-up was 2.3 years; median time to engraftment (absolute neutrophil count, >0.5 x 10(9)/L) was 13 days; 100% of patients with cytogenetic and/or molecular markers had documented chimerism; and there were no engraftment failures. Two-year overall and disease-free survival were 67% and 42%, respectively. There were no unexpected toxic reactions. Fatal veno-occlusive disease occurred in 2 patients, 1 of whom had undergone a prior transplantation. Treatment-related mortality at 100 days was 9.8% (6/61). Bu pharmacokinetics after IV drug administration demonstrated high inter- and intrapatient consistency; 86% of patients maintained an area under the curve between 800 and 1500 microMol-min. In conclusion, the IV Bu in this regimen was very well tolerated and demonstrated excellent antitumor efficacy, most likely because of dose assurance with predictable pharmacokinetics.

This trial compared the efficacy and toxicity of standard first-line treatment with paclitaxel/carboplatin versus paclitaxel/carboplatin plus sorafenib in patients with advanced ovarian carcinoma. Patients with stage 3 or 4 epithelial ovarian cancer with residual measurable disease or elevated CA-125 levels after maximal surgical cytoreduction were randomized (1:1) to receive treatment with paclitaxel (175 mg/m2, 3 h infusion, day 1) and carboplatin (AUC 6.0, IV, day 1) with or without sorafenib 400 mg orally twice daily (PO BID). Patients were reevaluated for response after completing 6 weeks of treatment (two cycles); responding or stable patients received six cycles of paclitaxel/carboplatin. Patients receiving the sorafenib-containing regimen continued sorafenib (400 PO BID) for a total of 52 weeks. Eighty-five patients were randomized and received treatment.Efficacy was similar for patients receiving paclitaxel/carboplatin/sorafenib versus paclitaxel/carboplatin: overall response rates 69% versus 74%; median progression-free survival 15.4 versus 16.3 months; 2 year survival 76% versus 81%. The addition of sorafenib added substantially to the toxicity of the regimen; rash, hand–foot syndrome, mucositis, and hypertension were significantly more common in patients treated with sorafenib. The addition of sorafenib to standard paclitaxel/carboplatin did not improve efficacy and substantially increased toxicity in the first-line treatment of advanced epithelial ovarian cancer. Based on evidence from this study and other completed trials, sorafenib is unlikely to have a role in the treatment of ovarian cancer.

Pretransplant conditioning therapy with i.v. BuCy followed by allogeneic hematopoietic stem cell transplantation (BMT) was investigated in a phase II trial in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). We gave i.v. Bu at a dose of 0.8 mg/kg every 6h x 16 doses, followed by Cy 60 mg/kg daily for 2 days. Twenty-six AML patients (18 males/eight females) were treated, only eight of whom were in CR1. The rest were either refractory to induction chemotherapy (four patients) or in a more advanced stage of their disease (14 patients). In addition, nine patients with MDS (1M/8F) were treated. Their median age was 41 years (range 21-64). Engraftment to > or =500 neutrophils/microl was reached at 14 days (range 10-29 days) post BMT, and the median time of neutropenia was only 11 days (range 4-28 days). The most common regimen-related toxicity was grade 2-3 nausea. In the post-BMT period (including BMT day +30), two patients died, one each from pulmonary hemorrhage secondary to CMV pneumonia and hepatic veno-occlusive disease (VOD), for an early treatment-related mortality (TRM) of 5.7%. Three patients developed VOD and two of them died. There was no direct regimen-related pulmonary or neurologic toxicity. Overall, the clinical side-effect spectrum was analogous to what would be expected from a high-dose oral Bu-based regimen; there was no unique toxicity experienced with the used solvent system. The disease-free survival in the high-risk subgroup (all patients not in CR1) at 1 and 2 years post transplant was 44% and 31%, respectively. The 13 patients still alive in CR have been followed for a median of 24 months (range 18-32). Pharmacokinetic analysis showed very good interdose reproducibility, and limited interpatient variability in area under the plasma concentration vs time curve, peak concentration, and clearance of Bu after this i.v. formulation. We conclude, that this new i.v. Bu formulation is well tolerated; it has an impressive safety profile, and we suggest that it should be considered as appropriate replacement for oral busulfan in pretransplant conditioning therapy prior to allogeneic BMT for patients with AML or MDS.

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