Dasatinib induces hematologic and cytogenetic responses in patients with CML or Ph-positive ALL who cannot tolerate or are resistant to imatinib. (ClinicalTrials.gov number, NCT00064233 [ClinicalTrials.gov].).
The BCR-ABL inhibitor dasatinib achieves clinical remissions in chronic myeloid leukemia (CML) patients using a dosing schedule that achieves potent but transient BCR-ABL inhibition. In vitro, transient potent BCR-ABL inhibition with either dasatinib or imatinib is cytotoxic to CML cell lines, as is transient potent EGFR inhibition with erlotinib in a lung cancer cell line. Cytotoxicity correlates with the magnitude as well as the duration of kinase inhibition. Moreover, cytotoxicity with transient potent target inhibition is equivalent to prolonged target inhibition and in both cases is associated with BIM activation and rescued by BCL-2 overexpression. In CML patients receiving dasatinib once daily, response correlates with the magnitude of BCR-ABL kinase inhibition, thereby demonstrating the potential clinical utility of intermittent potent kinase inhibitor therapy.
Developing strategies to counteract imatinib resistance constitutes a challenge in chronic myelogenous leukemia (CML). Therapy with the tyrosine kinase inhibitors nilotinib (AMN107) and dasatinib (BMS-354825) has produced high rates of hematologic and cytogenetic response. Src kinase activation has been linked to Bcr-Abl-mediated leukemogenesis and CML progression. In addition to binding Abl kinase with less stringent conformational requirements than imatinib, dasatinib is a potent Src kinase inhibitor. In the current study, we report on 23 patients with CML (19 of them in accelerated or blastic phases) treated with dasatinib after treatment failure with both imatinib and nilotinib. More than half (13; 57%) of 23 patients responded to dasatinib: 10 (43%) had a complete hematologic response (CHR), including 7 (30%) who had a cytogenetic response (2 complete, 4 partial, and 1 minor). These results suggest that dasatinib may be active in some patients after failure with both imatinib and nilotinib.
Murine monoclonal antibody (MAb) L6 binds to an antigen expressed on the surface of breast, colon, ovary, and nonsmall-cell lung cancer. This antibody effects antibody-dependent cellular cytotoxicity (ADCC) with human mononuclear cells and complement-dependent cytotoxicity (CDC) with human complement. Because of these activities, we conducted a phase I trial of MAb L6 in patients with advanced cancer. Nineteen patients whose tumors highly expressed antigen were selected for this trial. Eighteen were evaluable. MAb L6 was administered at dose levels ranging from 5 mg/m2/d to 400 mg/m2/d for 7 days and was well tolerated. The only side effects detected were fever and headaches at the highest dose levels. The serum half-life of L6 was directly related to dose and ranged from a mean of 7.7 hours at 5 mg/m2/d to 29.1 hours at 400 mg/m2/d. Peak serum concentrations ranged from 0.22 micrograms/mL to 362 micrograms/mL. Biopsies at the end of treatment showed L6 to localize well to tumor cells with apparent in vivo saturation occurring at dose levels above 100 mg/m2/d. Thirteen patients formed human antimouse antibodies (HAMA), some as early as day 13. One patient with recurrent breast cancer on the chest wall achieved a complete remission. The response was first noted at 5 weeks and a pathologic complete remission occurred at 14 weeks. Because of its favorable binding properties and the encouraging clinical effect observed, future evaluation of this MAb appears warranted.
A total of 353 patients with previously untreated small-cell lung cancer (SCLC) were accrued in this multicenter trial. Patients were randomly assigned to receive one of the following three regimens: cyclophosphamide 1,000 mg/m2 intravenously (IV) day 1, vincristine 1.4 mg/m2 IV day 1, and etoposide 50 mg/m2 IV day 1, followed by etoposide 100 mg/m2/day orally days 2 through 5 (CEV); cyclophosphamide 1,000 mg/m2 IV day 1, vincristine 1.4 mg/m2 IV day 1, and doxorubicin 50 mg/m2 IV day 1 (CAV); cyclophosphamide 2,000 mg/m2 day 1 and vincristine 1.4 mg/m2 IV day 1 (CV). Cycles were repeated every 3 weeks. Treatment groups were comparable with respect to extent of disease, age, sex, performance status, and metastatic sites. No significant differences in response rates, response duration, or survival could be detected in limited disease, although there appeared to be a trend favoring CEV. Among extensive-disease patients, response duration on the CEV regimen was longer than on the CV regimen or the CAV program (P less than .001). The superiority of the CEV regimen was also demonstrated in the survival analysis in which differences attained statistical significance (P = .01). In this group the median survival was increased from 29 weeks on CV to 31 weeks on CAV and 39 weeks on CEV. Myelosuppression was the most frequent toxicity. It was more severe with CV than CEV or CAV. Most nonhematologic side effects were comparable among the three treatment groups. However, the high doses of cyclophosphamide in the CV regimen produced a higher incidence of hemorrhagic cystitis than in the CEV or CAV programs (P less than .001). Cardiotoxicity only occurred in the CAV group (P = .05). The addition of etoposide to the CV regimen resulted in significantly longer response duration and survival without increased toxicity. Similarly, the substitution of etoposide for the doxorubicin in the CAV regimen was associated with prolonged survival and reduced cardiotoxicity.
We report a single institution phase I trial of chimeric (mouse-human) monoclonal antibody (chL6) directed against a tumor-associated cell surface antigen expressed in non-small cell lung, colon, and breast cancer. The results of the study were contrasted with a previous trial of murine L6. ChL6 was administered intravenously to 18 patients with advanced cancer as a single, 4-16 infusion in doses ranging from 350 mg/m2 to 700 mg/m2. One patient received four weekly doses of 350 mg/m2. Patients were followed for side effects, localization of antibody to tumor cells, pharmacokinetics and the development of antibodies against chL6. Side effects associated with treatment were chills, fever, and nausea, which lasted 24-48 hours. Platelet count and absolute leukocyte count fell immediately after treatment, but returned to pretreatment levels by day 7. Localization of chL6 to tumor cells in vivo was seen at 350 mg/m2 and "saturation" at 700 mg/m2 and 350 mg/m2 per week x 4. The pharmacokinetics of this antibody appeared similar to its murine analogue. Human antibodies against chL6 were detected in only 4 of 18 patients. These antibodies were directed against murine variable regent and their titers were lower than those occurring in most patients who received murine L6 in an earlier trial. No tumor reductions were seen. Chimeric L6 appears to be a suitable antibody for delivering anti-tumor agents because of its low immunogenicity and favorable in vivo tumor binding characteristics.
Twenty-six adult patients were entered in a phase I trial of carboplatin, a new cisplatin derivative with reduced potential for nephrotoxicity. All patients had solid tumors and the median World Health Organization performance score was 2 (0-3). Twelve patients had not received prior chemotherapy. The drug was administered as a 15-minute IV infusion, without pre- or posthydration, at daily doses of 40-125 mg/m2 for five consecutive days. Antiemetics were given only if needed. Thrombocytopenia and neutropenia were dose related and dose limiting. One patient died from septic shock at the highest dose level. Nonhemolytic anemia was also encountered. Nausea and vomiting were experienced by most patients but gastrointestinal intolerance was severe in only two patients. One patient had hypercreatininemia, which was minor and rapidly reversible. Other toxic effects consisted of negligible fatigue, paresthesia, pruritus, local pain, stomatitis, headache, and alopecia. Although none of the patients achieved a partial or complete response, antitumor effect was strongly suggested in two patients with thyroid and cervix cancer, respectively. Carboplatin is an attractive candidate for phase II trials. In good-risk patients, such trials could be initiated at a daily dose of 100 mg/m2 for five consecutive days every five to six weeks.
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