Clin Cancer Res
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Members of the epidermal growth factor receptor family of tyrosine kinases, including epidermal growth factor receptor, c-erbB-2 (HER-2), c-erbB-3 (HER-3), and c-erbB-4 (HER-4), can be coexpressed at different levels in nonhematopoietic tissues. Amplification and overexpression of HER-2 is found in approximately one-third of cancers that arise in the breast and ovary. In our previous studies, heregulin (HRG) and anti-HER-2 antibodies inhibited proliferation, increased invasiveness, and enhanced tyrosine autophosphorylation of SKBr3 breast cancer cells that overexpressed HER-2. ⋯ In ovarian cancer cells that express all three receptors, the relative levels of HER-2 and HER-3 appear to determine the response to HRG. Taken together, these studies support the concept that the level of HER-2 expression can modulate response to HRG, determining whether the response is stimulatory or inhibitory. In contrast, agonistic antibodies that bind to HER-2 alone inhibit anchorage-independent growth but fail to mimic HRG's ability to stimulate growth of cells with low HER-2: HER-3 ratios.
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Clinical Trial Controlled Clinical Trial
A phase I study of paclitaxel, etoposide, and cisplatin in extensive stage small cell lung cancer.
This Phase I study was designed to determine the maximally tolerated dose (MTD) of paclitaxel with standard doses of cisplatin and etoposide for patients with untreated extensive stage small cell lung cancer (SCLC). Secondary objectives were to determine the toxicities, response rate, response duration, and overall survival in this cohort. Twenty-eight SCLC patients were enrolled into four dose levels. ⋯ Neutropenia was frequent but not associated with significant morbidity. The recommended doses for future clinical trials are 175 mg/m2 paclitaxel, i.v., over a 3-h period on day 1 with 80 mg/m2 cisplatin, i.v., on day 1 and 80 mg/m2 etoposide, i.v., on day 1 and 160 mg/m2 p.o. on days 2 and 3 with growth factor support. The Southwestern Oncology Group has instituted a Phase II study with this dose schedule.
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i.v. paclitaxel is inconvenient and associated with significant and poorly predictable side effects largely due to the pharmaceutical vehicle Cremophor EL. Oral administration may be attractive because it may circumvent the use of Cremophor EL. However, paclitaxel, as well as many other commonly applied drugs, has poor bioavailability caused by high affinity for the mdrl P-glycoprotein drug efflux pump, which is abundantly present in the gastrointestinal tract. ⋯ In conclusion, coadministration of oral CsA increased the systemic exposure of oral paclitaxel from negligible to therapeutic levels. The combination enables treatment with oral paclitaxel. Undetectable Cremophor EL levels after oral administration may have a very beneficial influence on the safety of the treatment with oral paclitaxel.
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Dose-intensive chemotherapy appears to be important in the treatment of patients with recurrent solid tumors. Expanding upon our prior experience, we report the results of our most recent approach to administering dose-intensive therapy using four cycles of moderately high-dose chemotherapy with hematopoietic cell support for patients with metastatic breast cancer. This outpatient therapy includes high-dose melphalan, thiotepa, and paclitaxel for two cycles followed by mitoxantrone, thiotepa, and paclitaxel for two cycles, with each cycle supported with autologous peripheral blood progenitor cells (PBPCs). ⋯ This four-cycle regimen of high-dose combination therapy supported with hematopoietic progenitor cells is feasible, but it is associated with a range of posttransplant complications. The efficacy of such a treatment would have to be substantially superior to that of other currently available therapies, including single autologous transplant procedures, to justify the prolonged period of treatment, multiple episodes of pancytopenia, and associated toxicities, including infectious risks. G-CSF administration after each PBPC infusion appears to accelerate time to neutrophil recovery but does not affect red cell or platelet engraftment.