Docetaxel has the highest reported antitumor activity in anthracycline-resistant MBC. High objective response rates were seen in patients with visceral-dominant involvement, multiple metastatic sites, or extensive previous therapy. Docetaxel is associated with severe but reversible neutropenia, asthenia, and cumulative dose-related fluid retention. Dexamethasone decreased the frequency and severity of skin toxicity and appeared to ameliorate fluid retention.

Triciribine is a purine analogue which inhibits DNA and protein synthesis. We performed two studies to define its activity against metastatic breast cancer. The first study was a phase II study in 14 patients with metastatic breast cancer who had received two or fewer chemotherapy treatments. The treatment schedule was tricirbine 20 mg/m2 per day by 24-h infusion (CI) daily for 5 days every 6 weeks as recommended by a previous open phase I trial. When neither response nor toxicity was seen in the phase II trial, we assumed the starting dose was too low for this group of patients with good performance status and repeated the phase I trial in patients with metastatic breast cancer with good performance status. The starting dose was 35 mg/m2 per day using the same 5-day CI schedule, and starting doses were increased in subsequent cohorts of three patients in increments of 5 mg/m2 until toxicity occurred. In the initial (phase II) study, one patient had stable disease for 18 weeks (three courses), the remainder progressed. There were no significant toxic effects. In the subsequent phase I study, ten patients were treated until the study was closed. The maximum dose was 40 mg/m2. Two patients died, one each at the 35 and 40 mg/m2 levels, respectively, 3 months and 6 weeks after their last course, one without intervening disease progression. Both had severe hypertriglyceridemia (18- and 21-fold elevation) and severe fatigue. At postmortem examination, one had congestive cardiomyopathy, and the other had severe pancreatitis and hypothyroidism. One patient had severe exacerbation of psoriasis which made her bedridden for more than 30 days. Four patients had hyperglycemia. Plasma pharmacology studies showed erratic drug levels, presumably related to enterohepatic circulation. Postmortem pharmacology studies showed residual drug present as long as 12 weeks after the last dose. We conclude that triciribine is ineffective at all doses tested and at doses of > or = 35 mg/m2 has unacceptable toxic effects.

Sixteen evaluable patients with metastatic breast cancer were entered into a phase II trial of didemnin B. They received the drug at an initial dose of 5.6 mg/m2 every 21 to 28 days. Major toxicities noted were myalgia and nausea and vomiting while myelosuppression was mild. There were no complete responses; however, two minor responses were observed. The pharmacokinetics of didemnin B were studied in 10 patients who received the drug as 30 to 60 min i.v. infusions. A sensitive competitive inhibition enzyme immunoassay was used to quantitate didemnin B levels. Drug was observed to be rapidly cleared from plasma in a biphasic manner (t1/2 alpha = 0.12 hr, t1/2 beta = 4.8 hr). Although the assay could not identify the presence of specific metabolites, the increase of apparent didemnin B levels in plasma at later time points suggested the formation of unidentified metabolites which cross reacted with the antibody in the analytical procedure. In vitro experiments indicated that didemnin B was not bound to bovine serum albumin and only a minor portion (24%) of drug was found associated with red blood cells.

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We assessed the antiemetic efficacy and safety of three different oral doses of ondansetron (GR 38032F), a novel serotonin type-3 receptor antagonist, in three consecutive series of 20 breast cancer patients receiving cyclophosphamide-doxorubicin-based chemotherapy for the first time. Patients received oral doses of 8 mg, 4 mg, or 1 mg of ondansetron three times daily for 2 days, with the first dose given 30 minutes before the cyclophosphamide infusion. We then evaluated the efficacy of a conventional antiemetic regimen of intravenous lorazepam, metoclopramide, and diphenhydramine given before chemotherapy and 10 mg prochlorperazine given orally twice on study day 1 and three times on study day 2 in a fourth series of 20 patients with comparable characteristics. The number of emetic episodes, assessment of nausea and appetite, and adverse events were recorded throughout the 2-day study period. Pretreatment and posttreatment clinical laboratory data were also collected. No emesis was observed during the 2-day study period in 17 (85%), 13 (65%), and 11 (55%) patients treated with 8-mg, 4-mg, and 1-mg ondansetron doses, respectively, and in seven (35%) patients who received conventional therapy. The incidence and intensity of nausea were lower with increasing doses of ondansetron and were lower than in the conventional group. Ondansetron-related side effects were generally mild and reversible and did not appear to increase in a dose-dependent manner. These effects included headache, stomach cramps, diarrhea, fatigue, and elevated serum transaminase concentrations. One patient who received three 1 mg doses of ondansetron experienced tremors and muscle twitching. Oral ondansetron is an effective and safe antiemetic for patients receiving noncisplatin cyclophosphamide-doxorubicin-based chemotherapy, and its antiemetic activity appears to be dose-related.