Marianne Noone

Effect of R-verapamil on the pharmacokinetics of paclitaxel in women with breast cancer.

PURPOSE To study the effect of the multidrug-resistance reversal agent R-verapamil on the pharmacokinetic behavior of paclitaxel. METHODS Six women with breast cancer who received paclitaxel as a 3-hour infusion with and without R-verapamil were monitored with frequent plasma sampling up to 24 hours postinfusion. Paclitaxel concentrations were measured using a reverse-phase high-pressure liquid chromatography assay. RESULTS Concomitant administration of R-verapamil resulted in a decrease in mean (+/- SD) paclitaxel clearance from 179 +/- 67 mL/min/m2 to 90 +/- 34 mL/min/m2 (P < .03) and in a twofold increase in paclitaxel exposure (area under the curve [AUC]). The mean end-infusion paclitaxel concentration was also twofold higher: 5.1 +/- 1.8 mumol/L versus 11.3 +/- 4.1 mumol/L (P < .03). CONCLUSION The alteration in paclitaxel pharmacokinetics when paclitaxel and R-verapamil are coadministered complicates the interpretation of response and toxicity data from clinical trials of this drug combination.

Phase I/II study of 72-hour infusional paclitaxel and doxorubicin with granulocyte colony-stimulating factor in patients with metastatic breast cancer.

PURPOSE We conducted a phase I/II trial of concurrently administered 72-hour infusional paclitaxel and doxorubicin in combination with granulocyte colony-stimulating factor (G-CSF) in patients with previously untreated metastatic breast cancer and bidimensionally measurable disease. PATIENTS AND METHODS We defined the maximum-tolerated dose (MTD) of concurrent paclitaxel and doxorubicin administration and then studied potential pharmacokinetic interactions between the two drugs. Forty-two patients who had not received prior chemotherapy for metastatic breast cancer received 296 total cycles of paclitaxel and doxorubicin with G-CSF. RESULTS The MTD was determined to be paclitaxel 180 mg/m2 and doxorubicin 60 mg/m2 each by 72-hour infusion with G-CSF. Diarrhea was the dose-limiting toxicity (DLT) of this combination, with three of three patients developing abdominal computed tomographic (CT) scan evidence of typhlitis (cecal thickening) at the dose level above the MTD. All patients developed grade 4 neutropenia (absolute neutrophil count [ANC] < 500 microL), generally less than 5 days in duration. This combination was generally safely administered at dose levels at or below the MTD. The overall response rate was 72% (28 of 39 patients; 95% confidence interval [CI], 55% to 85%), with 8% complete responses (CRs) (three of 39; 95% CI, 2% to 21%) and a median response duration of 9 months. The median overall survival time for all patients is 23 months, with a median follow-up duration of 28 months. Pharmacokinetic studies showed that administration of paclitaxel and doxorubicin together by 72-hour infusion did not affect the steady-state concentrations of either drug. CONCLUSION Concurrent 72-hour infusional paclitaxel and doxorubicin can be administered safely, but is associated with significant toxicity. The overall response rate of this combination in untreated metastatic breast cancer patients is similar to that achieved with other doxorubicin-based combination regimens. The modest complete response rate achieved suggests that this schedule of paclitaxel and doxorubicin administration does not produce significant additive or synergistic cytotoxicity against breast cancer.

Phase I crossover study of paclitaxel with r-verapamil in patients with metastatic breast cancer.

PURPOSE We conducted a phase I crossover study of escalating doses of both paclitaxel (Taxol; Bristol-Myers, Squibb, Princeton, NJ) and r-verapamil, the less cardiotoxic stereoisomer, in heavily pretreated patients with metastatic breast cancer. PATIENTS AND METHODS Twenty-nine patients refractory to paclitaxel by 3-hour infusion were treated orally with r-verapamil every 4 hours starting 24 hours before the same-dose 3-hour paclitaxel infusion and continuing for a total of 12 doses. Once the maximum-tolerated dose (MTD) of the combination was determined, seven additional patients who had not been treated with either drug were evaluated to determine whether the addition of r-verapamil altered the pharmacokinetics of paclitaxel. Consenting patients had tumor biopsies for P-glycoprotein (Pgp) expression before receiving paclitaxel and after becoming refractory to paclitaxel therapy. RESULTS The MTD of the combination was 225 mg/m2 of r-verapamil every 4 hours with paclitaxel 200 mg/m2 by 3-hour infusion. Dose-limiting hypotension and bradycardia were observed in three of five patients treated at 250 mg/m2 r-verapamil. Fourteen patients received 32 cycles of r-verapamil at the MTD as outpatient therapy without developing cardiac toxicity. The median peak and trough serum verapamil concentrations at the MTD were 5.1 micromol/L (range, 1.9 to 6.3), respectively, which are within the range necessary for in vitro modulation of Pgp-mediated multidrug resistance (MDR). Increased serum verapamil concentrations and cardiac toxicity were observed more frequently in patients with elevated hepatic transaminases and bilirubin levels. Hematologic toxicity from combined paclitaxel and r-verapamil was significantly worse compared with the previous cycle of paclitxel without r-verapamil. In the pharmacokinetic analysis, r-verapamil delayed mean paclitaxel clearance and increased mean peak paclitaxel concentrations. CONCLUSION r-Verapamil at 225 mg/m2 orally every 4 hours can be given safely with paclitaxel 200 mg/m2 by 3-hour infusion as outpatient therapy and is associated with serum levels considered active for Pgp inhibition. The addition of r-verapamil significantly alters the toxicity and pharmacokinetics of paclitaxel.

Phase I Clinical Trial of Alitretinoin and Tamoxifen in Breast Cancer Patients: Toxicity, Pharmacokinetic, and Biomarker Evaluations

PURPOSE To determine the overall and dose-limiting toxicities (DLTs) of alitretinoin (9-cis-retinoic acid) in combination with tamoxifen and the pharmacokinetics of alitretinoin alone and when combined with tamoxifen in patients with metastatic breast cancer. The effect of tamoxifen and alitretinoin on MIB-1, a marker of proliferation, in unaffected breast tissue was explored. PATIENTS AND METHODS Eligible patients had metastatic breast cancer. Previous tamoxifen therapy was allowed. Planned dose levels for alitretinoin ranged from 50 to 140 mg/m2/d with 20 mg/d tamoxifen in all patients after 4 weeks of alitretinoin as a single agent. Plasma concentrations of alitretinoin and retinol were measured at baseline and after 1, 2, and 3 months. Breast core biopsies were obtained at baseline and after 2 months of therapy. RESULTS Twelve patients with metastatic breast cancer received a total of 86 cycles of therapy. At 90 mg/m2/d, three of five patients experienced a DLT: grade 3 headache, grade 3 hypercalcemia, and grade 3 noncardiogenic pulmonary edema. At 70 mg/m2/d, one of six patients experienced a DLT (headache), and this level was considered the maximal tolerated dose in this study. Three toxicities occurred that had not been reported previously with alitretinoin: an asymptomatic delay in dark adaptation, a marked decrease in high-density lipoprotein cholesterol, and the occurrence of enthesopathy. Two of the nine assessable patients had a durable clinical response: one partial response and stable disease for 18 months and one complete response in continuous remission for 48+ months. Both responding patients were estrogen receptor-positive and had had previous tamoxifen therapy. There was a high degree of interpatient variability of plasma alitretinoin concentrations, although a significant decline in alitretinoin plasma levels over time was observed. MIB-1 scores declined in four of the eight paired breast specimens obtained. CONCLUSION The combination of tamoxifen and alitretinoin is well tolerated and has antitumor activity in metastatic breast cancer. The recommended phase II dose is 70 mg/m2/d with 20 mg/d tamoxifen.

Selection of local therapy after neoadjuvant chemotherapy in patients with stage IIIA,B breast cancer

AbstractBackground: Stage IIIA,B breast cancer is commonly treated with neoadjuvant chemotherapy because of high objective response rates and improved operability. Criteria for subsequent selection of local therapy—mastectomy, radiotherapy, or both—are not well defined. We adopted a policy of selective local therapy based on rebiopsy of the breast and clinical axillary lymph node status at the time of best response to chemotherapy. Methods: Between 1980 and 1993, 126 patients with stage IIIA,B breast cancer were treated with neoadjuvant chemotherapy and definitive local therapy. The long-term incidence of locoregional failure (in-breast, chest wall, axilla, supraclavicular, neck), relapse-free survival, and overall survival was determined. Results: The overall clinical objective response rate to chemotherapy was 95.2%. Eighty-three patients underwent mastectomy, with negative margins achieved in 91.6%. Forty-two patients had breast preservation; the overall in-breast recurrence rate was 19.0% (8 of 42 patients). The overall locoregional recurrence rate by site was: chest wall—8.7% (11 of 126 patients), axilla—8.7% (11 of 126 patients), supraclavicular—5.6% (7 of 126 patients), and neck—4.0% (5 of 126 patients). The axillary recurrence rate was 6.6% (5 of 76 patients) for clinically negative axilla treated with radiotherapy only, and 12.0% (6 of 50 patients) for clinically positive axilla treated with surgery only. The overall long-term survival probabilities (6 years) according to stage were: stage IIIA—58.0%, stage IIIBnoninflam—58.0%, stage IIIBinflam—36.0%. Conclusions: These findings support a selective approach to local therapy in patients with stage IIIA,B breast cancer. This approach provides local control in most patients, and allows for breast preservation and elimination of axillary dissection in selected patients.

Phase I study of paclitaxel in combination with cyclophosphamide and granulocyte colony-stimulating factor in metastatic breast cancer patients.

PURPOSE In vitro data suggest that prolonged exposure to paclitaxel enhances breast cancer cytotoxicity. Our objective in this phase I study was to determine the tolerability of paclitaxel administered by 72-hour continuous intravenous (i.v.) infusion (CIVI) in combination with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) in the ambulatory setting to metastatic breast cancer patients. PATIENTS AND METHODS Paclitaxel was administered over 72 hours by CIVI and cyclophosphamide was given daily by i.v. bolus on days 1, 2, and 3, followed by G-CSF every 21 days. The availability of ambulatory infusion pumps and paclitaxel-compatible tubing permitted outpatient administration. RESULTS Fifty-five patients with metastatic breast cancer who had been previously treated with a median of two prior chemotherapy regimens were entered onto the study. Dose-limiting toxicity of grade 4 neutropenia for longer than 5 days and grade 4 thrombocytopenia occurred in three of five patients treated with paclitaxel 160 mg/m2 CIVI and cyclophosphamide 3,300 mg/m2 followed by G-CSF. The maximum-tolerated dose (MTD) was paclitaxel 160 mg/m2 CIVI and cyclophosphamide 2,700 mg/m2 in divided doses with G-CSF. Nonhematologic toxicities were moderate and included diarrhea, mucositis, and arthalgias. Although hemorrhagic cystitis developed in six patients, recurrence was prevented with i.v. and oral mesna, which permitted continued outpatient delivery. One hundred seventy-four cycles were safely administered in the ambulatory setting using infusional pumps and tubing. Objective responses occurred in 23 (one complete and 22 partial) of 42 patients with bidimensionally measurable disease (55%; 95% confidence interval, 38% to 70%), with a response rate of 73% (11 of 15) seen at the highest dose levels. CONCLUSION Paclitaxel by 72-hour CIVI with daily cyclophosphamide followed by G-CSF can be administered safely in the ambulatory setting, has acceptable toxicity, and is an active regimen in the treatment of metastatic breast cancer.

Early suppressive effects of chemotherapy and cytokine treatment on committed versus primitive haemopoietic progenitors in patient bone marrow

These studies investigated the effectiveness of in vivo administration of cytokines in ameliorating potential marrow damage induced by chemotherapy. Breast cancer patients received 5‐fluorouracil, leucovorin, doxorubicin and cyclophosphamide (FLAC) followed by either GM‐CSF, PIXY321, or no cytokine. Marrow was obtained before and after one or two cycles of FLAC once blood cell counts had recovered. Colony‐forming units for granulocytes and macrophages (CFU‐GM) were used to indicate the effect of therapy on recovery of committed progenitor cells responsible for early blood cell recovery. The frequency and number of CFU‐GM in marrow obtained after FLAC + PIXY321 were significantly lower than in marrow obtained after FLAC + GM‐CSF or FLAC without cytokine. CD34+ cell numbers were also reduced after FLAC + PIXY321. CFU‐GM production in marrow long‐term cultures (LTC) was used to assess the effect of therapy on primitive progenitors. After 5 weeks the number of CFU‐GM in LTC of post‐therapy marrow from all three treatment arms was < 15% of the number in pre‐therapy LTC. Suppressive effects of FLAC on primitive progenitors were observed even when committed progenitors and CD34+ cells had recovered to pre‐therapy levels. These results demonstrate that cytokine treatment did not ameliorate suppressive or toxic effects of FLAC on the functional integrity of the marrow.