Targeted Therapies

Formerly BioOncology Watch

www.tgt-therapies.com

SEPTEMBER 2005

 

NON-SMALL-CELL LUNG CANCER (NSCLC)

Erlotinib; clinical and molecular results. Two reports from the National Cancer Institute of Canada (NCIC) detail the clinical results (Shepherd and colleagues) and molecular results (Tsao and colleagues) of a randomized, double-blind trial comparing the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib with placebo. The study population consisted of 731 patients with advanced NSCLC who had received one or two prior chemotherapy regimens (platinum-based in 93% of patients). An objective response was achieved in 8.9% of erlotinib-treated patients compared with <1% of placebo patients (P <0.001). The median duration of response to erlotinib was 7.9 months, and progression-free survival was 2.2 months in the erlotinib group and 1.8 months in the placebo group (P <0.001). Median overall survival was greater in patients treated with erlotinib than in patients who received placebo (6.7 vs 4.7 months; P <0.001). Multivariate analysis showed that adenocarcinoma, lack of a smoking history, and expression of EGFR were associated with tumor response but not overall survival. Rash and diarrhea were the most frequent causes of erlotinib dose reductions (reported in 19% of patients), but only 5% of patients permanently discontinued erlotinib due to adverse events. These results demonstrate that erlotinib can prolong survival in patients with previously treated NSCLC. (Shepherd FA, et al. N Engl J Med. 2005;353:123–132 and Tsao M-S, et al. N Engl J Med. 2005;353:133–144.)

 

BREAST CANCER

Trastuzumab plus docetaxel. Marty and associates conducted a multicenter study in which 186 patients with previously untreated HER-2–positive metastatic breast cancer were randomized to receive six cycles of docetaxel (100 mg/m2 every 3 weeks) plus trastuzumab (4 mg/kg loading dose followed by 2 mg/kg weekly until disease progression) or six cycles of docetaxel alone. Combination therapy yielded a response rate of 61% compared with 34% with docetaxel alone. Median duration of response (11.7 vs 5.7 months), time to progression (11.7 vs 6.1 months), and overall survival time (31.2 vs 22.7 months) were greater in patients treated with trastuzumab plus docetaxel compared with docetaxel alone. Grade 3 to 4 neutropenia developed more frequently in the combination arm (32% vs 22%); however, febrile neutropenia occurred only slightly more commonly in this group (23% vs 17%). These data show that the addition of trastuzumab to docetaxel was well tolerated and improved efficacy in previously untreated patients with HER-2–positive metastatic breast cancer. (Marty M, et al. J Clin Oncol 2005;23:4265–4274.)

 

NON-HODGKIN'S LYMPHOMA

Phase I/II study of galiximab. Galiximab is a monoclonal antibody directed against CD80, a membrane bound co-stimulatory molecule constitutively expressed on a variety of lymphomas. Czuczman and coworkers performed a multicenter, dose-finding study of galiximab in 37 patients with relapsed or refractory follicular lymphoma. Four weekly infusions of galiximab 125, 250, 375, or 500 mg/m2 were administered. The overall response rate was 11% (two complete and two partial responses), and 12 patients maintained stable disease. Two responders had not developed disease progression at 22 and 24.4 months of follow-up, respectively. The most common adverse events associated with galiximab were grade 1 or 2 fatigue, nausea, and headache. The development of anti-galiximab antibodies was not observed. These data demonstrate that galiximab has a favorable safety profile and is active against follicular lymphoma. (Czuczman MS, et al. J Clin Oncol. 2005;23:4390–4398.)

 

HODGKIN'S DISEASE

Treatment with radioimmunotherapy. CD30, a lymphocyte activation marker, is expressed in high numbers on the malignant cells of Hodgkin's disease. This finding led Schnell and others to develop a radioimmunoconjugate consisting of a murine anti-CD30 monoclonal antibody (Ki-4) labeled with iodine-131 (131I). Twenty-two patients with relapsed or refractory CD30-positive Hodgkin's disease were treated with 131I-Ki-4. A preinfusion of native Ki-4 5 mg was found to be sufficient to bind soluble CD30. The therapeutic dose of 131I-Ki-4 was given 1 week after the infusion of unlabeled Ki-4. Whole-body scintigraphy demonstrated uptake of the radioimmunoconjugate in four patients with tumor masses >5 cm and one patient with a thoracic mass of 2.5 cm. Tumor visualization was difficult due to the limited resolution of the gamma camera, the modest uptake of 131I-Ki-4, and the adjacent blood pool activity. Six patients achieved an objective response and three patients had minor responses. Seven patients experienced grade 4 neutropenia or thrombocytopenia 4 to 8 weeks after treatment. These results indicate 131I-Ki-4 is a potentially effective treatment against relapsed or refractory Hodgkin's disease. (Schnell R, et al. J Clin Oncol. 2005;23:4669–4678.)

 

PHILADELPHIA CHROMOSOME-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA (Ph+ ALL)

Post-transplantation imatinib therapy. The detection of minimal residual disease (MRD) following stem cell transplantation (SCT) in patients with Ph+ ALL is associated with a relapse risk of >90%. Wassman and colleagues treated 27 patients who had Ph+ ALL with imatinib upon detection of MRD after SCT. The starting dose of imatinib was 400 mg/d, and dose escalation to 800 mg/d was permitted for patients who remained bcr-abl–positive. Bcr-abl transcripts became negative by polymerase chain reaction (PCR) assay in 14 patients (52%) after a median of 1.5 months (0.9 to 3.7 months) of imatinib therapy. The disease-free and overall survival rates were 91% ± 9% and 100%, respectively, at 1 year for patients who became MRD-negative with imatinib treatment compared with 8% ± 7% and 23% ± 13%, respectively, at 13 months in patients who remained MRD-positive. These data demonstrate that an early complete molecular remission induced by imatinib in MRD-positive patients with Ph+ ALL following SCT is associated with improved clinical outcomes. Patients in whom bcr-abl transcripts continue to be detected after approximately 3 months of imatinib therapy require additional/alternative antileukemic treatment. (Wassman B, et al. Blood. 2005;106:458–463.)

 

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