Susan M. Galbraith

Combretastatin A4 Phosphate Has Tumor Antivascular Activity in Rat and Man as Demonstrated by Dynamic Magnetic Resonance Imaging

PURPOSEnCombretastatin A4 phosphate (CA4P) is a novel vascular targeting agent. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) studies were performed to examine changes in parameters related to blood flow and vascular permeability in tumor and normal tissue after CA4P treatment.nnnMATERIALS AND METHODSnChanges in kinetic DCE-MRI parameters (transfer constant [Ktrans] and area under contrast medium-time curve [AUC]) over 24 hours after treatment with CA4P were measured in 18 patients in a phase I trial and compared with those obtained in the rat P22 carcinosarcoma model, using the same imaging technique. Rats were treated with 30 mg/kg of CA4P; patients received escalating doses from 5 to 114 mg/m2.nnnRESULTSnA similar pattern and time course of change in tumor and normal tissue parameters was seen in rats and humans. Rat tumor Ktrans was reduced by 64% 6 hours after treatment with CA4P (30 mg/kg). No significant reductions in kidney or muscle parameters were seen. Significant reductions were seen in tumor Ktrans in six of 16 patients treated at >or= 52 mg/m2, with a significant group mean reduction of 37% and 29% at 4 and 24 hours, respectively, after treatment. The mean reduction in tumor initial area under the gadolinium-diethylenetriamine pentaacetic acid concentration-time curve (AUC) was 33% and 18%, respectively, at these times. No reduction was seen in muscle Ktrans or in kidney AUC in group analysis of the clinical data.nnnCONCLUSIONnCA4P acutely reduces Ktrans in human as well as rat tumors at well-tolerated doses, with no significant changes in kidney or muscle, providing proof of principle that this drug has tumor antivascular activity in rats and humans.

Phase I Clinical Trial of Weekly Combretastatin A4 Phosphate: Clinical and Pharmacokinetic Results

PURPOSEnA phase I trial was performed with combretastatin A4 phosphate (CA4P), a novel tubulin-binding agent that has been shown to rapidly reduce blood flow in animal tumors.nnnPATIENTS AND METHODSnThe drug was delivered by a 10-minute weekly infusion for 3 weeks followed by a week gap, with intrapatient dose escalation. Dose escalation was accomplished by doubling until grade 2 toxicity was seen. The starting dose was 5 mg/m2.nnnRESULTSnThirty-four patients received 167 infusions. CA4P was rapidly converted to the active combretastatin A4 (CA4), which was further metabolized to the glucuronide. CA4 area under the curve (AUC) increased from 0.169 at 5 mg/m2 to 3.29 micromol * h/L at 114 mg/m2. The mean CA4 AUC in eight patients at 68 mg/m2 was 2.33 micromol * h/L compared with 5.8 micromol * h/L at 25 mg/kg (the lowest effective dose) in the mouse. The only toxicity that possibly was related to the drug dose up to 40 mg/m2 was tumor pain. Dose-limiting toxicity was reversible ataxia at 114 mg/m2, vasovagal syncope and motor neuropathy at 88 mg/m2, and fatal ischemia in previously irradiated bowel at 52 mg/m2. Other drug-related grade 2 or higher toxicities seen in more than one patient were pain, lymphopenia, fatigue, anemia, diarrhea, hypertension, hypotension, vomiting, visual disturbance, and dyspnea. One patient at 68 mg/m2 had improvement in liver metastases of adrenocortical carcinoma.nnnCONCLUSIONnCA4P was well tolerated in 14 of 16 patients at 52 or 68 mg/m2; these are doses at which tumor blood flow reduction has been recorded.

Randomized Phase III Study of Matrix Metalloproteinase Inhibitor BMS-275291 in Combination With Paclitaxel and Carboplatin in Advanced Non-Small-Cell Lung Cancer: National Cancer Institute of Canada-Clinical Trials Group Study BR.18

PURPOSEnTo determine whether BMS-275291, a broad-spectrum matrix metalloproteinase inhibitor (MMPI), added to systemic chemotherapy improved survival in advanced non-small-cell lung cancer (NSCLC). In early phase studies, BMS- 275291 was not associated with dose-limiting joint toxicity seen with other MMPIs.nnnPATIENTS AND METHODSnChemotherapy-naive patients with stage IIIB/IV NSCLC, performance status (PS) 0 to 2, and adequate organ function were eligible. All patients received paclitaxel 200 mg/m2 plus carboplatin (area under the curve, 6 mg/mL-min) intravenously every 21 days for up to 8 cycles, and were randomly assigned to receive BMS-275291, 1,200 mg orally daily, or placebo until disease progression. The primary study end point was survival (OS); secondary end points included progression-free survival (PFS), response rates (RR), toxicity, and quality of life.nnnRESULTSnFrom 2000 to 2002, 774 patients were randomly assigned. Pretreatment characteristics were well balanced between arms: median age, 61 years; male sex, 73%; stage IV, 79%; PS 0 to 1, 88%. Interim safety analysis revealed no survival advantage and increased toxicity in the experimental arm, and study treatment was stopped. Median OS, PFS and RR in the final analysis in the BMS-275291 arm were 8.6 months, 4.9 months, and 25.8% respectively, and in the control arm 9.2 months, 5.3 months, 33.7%. Toxicity was significantly higher in the BMS-275291 arm, including flu-like symptoms, rash, hypersensitivity reactions (8.6% v 2.4%), and febrile neutropenia (9.7% v 5.5%).nnnCONCLUSIONnBMS-275291 added to chemotherapy increases toxicity and does not improve survival in advanced NSCLC.

Phase II Genomics Study of Ixabepilone as Neoadjuvant Treatment for Breast Cancer

PURPOSEnThis phase II study evaluated the efficacy and safety of ixabepilone as neoadjuvant therapy for invasive breast cancer not amenable to breast conservation surgery. Gene expression studies were undertaken using genes that were identified as potentially associated with sensitivity/resistance to ixabepilone in prior preclinical investigations.nnnPATIENTS AND METHODSnPatients with invasive breast cancer >or= 3 cm were eligible. Ixabepilone 40 mg/m(2) was administered as a 3-hour intravenous infusion on day 1 of a 21-day cycle for four or fewer cycles.nnnRESULTSnOne hundred sixty-one patients were treated. The overall complete pathologic response (pCR) rate was 18% in breast and 29% in estrogen receptor (ER) -negative patients. Gene expression data were available for 134 patients. ER gene expression (ER1) was inversely related to pCR in breast and had a positive predictive value (PPV) of 37% and negative predictive value (NPV) of 92%. A 10-gene penalized logistic regression (PLR) model developed from 200 genes predictive of ixabepilone sensitivity in preclinical experiments included ER and tau and had higher PPV (45%) and comparable NPV (89%) to ER1. Grade 3 to 4 adverse events (AEs) were reported for 32% of patients. Except for neutropenia and leukopenia, all grade 3 to 4 AEs occurred in <or= 3% of patients. Reversible peripheral neuropathy was experienced by 3% of patients. CONCLUSION ER, microtubule-associated protein tau, and a 10-gene PLR model that included ER were identified as predictors of ixabepilone-induced pCR.nnnRESULTSnindicate an inverse relation between ER expression levels and ixabepilone sensitivity. Neoadjuvant ixabepilone demonstrated promising activity and a manageable safety profile in patients with invasive breast tumors.