Multicenter Phase II Feasibility Trial of High-Dose Tamoxifen in Patients With Refractory or Relapsed Multiple Myeloma (original) (raw)
Related papers
Clinical Cancer Research, 2004
Purpose: Both therapeutic and adverse effects of tamoxifen may be related to its tissue concentrations. We investigated concentrations of tamoxifen, 4-hydroxytamoxifen, Ndesmethyltamoxifen, and N-didesmethyltamoxifen in serum, normal breast, and breast cancer tissues during conventional dosage and two low-dose regimens. Furthermore we studied tamoxifen effects on the cancer proliferation marker Ki-67, and on sex hormone-binding globulin (SHBG). Experimental Design: From September 1999 to August 2001, 120 breast cancer patients were randomized to 20-, 5-, or 1-mg tamoxifen daily. We measured serum and tissue concentrations of tamoxifen and three metabolites after 28 days of treatment, and the changes between baseline and post-treatment levels of SHBG and Ki-67. Results: The median (range) tamoxifen concentrations (ng/ml) at doses of 1, 5, and 20 mg daily (n ؍ 38, 37, and 36) were 7.5 (2.9-120.9), 25.2 (1.9-180.9), and 83.6 (8.7-134.4) in serum, and 78.2 (35.9-184), 272.3 (122-641), and 744.4 (208.6-2556) in breast cancer tissue, respectively. Tamoxifen levels followed a dose-concentration relationship. The concentrations of tamoxifen and metabolites were related to each other. Serum and tissue concentrations of tamoxifen were associated with corresponding changes of SHBG levels, whereas changes of Ki-67 levels were not related. Conclusions: Estrogen agonistic effects of tamoxifen on SHBG decreased with lower dosage, whereas tamoxifen effects on Ki-67 expression did not change. This together with a >10-fold variation in serum tamoxifen concentrations and a serum to tissue concentration relationship suggest that tamoxifen treatment may be improved by administration of lower doses and therapeutic drug monitoring.
JNCI Journal of the National Cancer Institute, 2003
Background: Tamoxifen reduces the risk of breast cancer in women at high risk for the disease but increases the risk for endometrial tumors and venous thromboembolisms, possibly in a dose-dependent fashion. We compared the effects of tamoxifen at 1 mg/day and 5 mg/day with those of the standard dose of 20 mg/day on breast cancer proliferation using a surrogate endpoint marker (Ki-67 expression) and blood biomarkers associated with breast cancer, cardiovascular disease, and bone fracture risk. Methods: We randomly assigned 120 women with estrogen receptor (ER)-positive breast cancer to tamoxifen at 1, 5, or 20 mg/day for 4 weeks. Expression of the tumor proliferation marker Ki-67 and of biomarkers of breast cancer (insulin-like growth factor-I, sex hormone-binding globulin), cardiovascular disease (cholesterol, triglycerides, ultrasensitive C-reactive protein, fibrinogen, antithrombin-III), and bone fracture (type I collagen C-telopeptide) risk were determined before (baseline) and after treatment. All levels were compared with those in two nonrandomized control groups (34 women with ER-negative breast cancer and 29 additional women with ER-positive breast cancer). Data were analyzed by analysis of covariance. All statistical tests were two-sided. Results: Expression of Ki-67 decreased in all three tamoxifen groups, with no difference in the magnitude of reduction among groups (P = .81). Relative to baseline, Ki-67 expression decreased by a median of 15.0% (95% confidence interval = 0.0% to 24.1%) among the tamoxifen groups but increased by 12.8% (95% confidence interval = 0.0% to 19.6%) among the nonrandomized control groups. Several blood biomarkers showed dose-response relationships with tamoxifen, including decreased insulin-like growth factor-I, increased sex hormone-binding globulin, and decreased lowdensity lipoprotein-cholesterol, ultrasensitive C-reactive protein, fibrinogen, and antithrombin-III levels. Conclusions: The effects on Ki-67 expression of lower doses of tamoxifen were comparable to those achieved with the standard dose, although the effects on blood biomarkers were variable. The effects of lower doses of tamoxifen should be assessed further in randomized trials. [J Natl Cancer Inst 2003;95:779-90] a total of 236 women were registered, and 221 were assessed to determine their eligibility for the study . Of those women assessed, 38 were excluded primarily because no tumor tissue was obtained from the core biopsy, thus leaving 183 women available for analysis. The summary statistics for the subject demographics and tumor characteristics at baseline are presented in .
BMC Cancer, 2010
Background: The cytochrome P450 (CYP) enzymes 2C19, 2D6, and 3A5 are responsible for converting the selective estrogen receptor modulator (SERM), tamoxifen to its active metabolites 4-hydroxy-tamoxifen (4OHtam) and 4hydroxy-N-demethyltamoxifen (4OHNDtam, endoxifen). Inter-individual variations of the activity of these enzymes due to polymorphisms may be predictors of outcome of breast cancer patients during tamoxifen treatment. Since tamoxifen and estrogens are both partly metabolized by these enzymes we hypothesize that a correlation between serum tamoxifen and estrogen levels exists, which in turn may interact with tamoxifen on treatment outcome. Here we examined relationships between the serum levels of tamoxifen, estrogens, follicle-stimulating hormone (FSH), and also determined the genotypes of CYP2C19, 2D6, 3A5, and SULT1A1 in 90 postmenopausal breast cancer patients.
The Royal Marsden Hospital pilot tamoxifen chemoprevention trial
Breast Cancer Research and Treatment, 1994
A pilot randomised placebo controlled trial using tamoxifen in healthy women at increased risk of developing breast cancer, has been undertaken in order to evaluate the problems of accrual, acute symptomatic toxicity, compliance, and safety as a basis for subsequent large national multicentre trials designed to test whether tamoxifen can chemoprevent breast cancer. From October 1986 until June 1993, 2012 healthy women with an increased risk of developing breast cancer, usually because of a strong family history, were randomly allocated to receive tamoxifen 20 rags/day or placebo for up to 8 years if possible. Accrual remained high in spite of extensive informed consent regarding potential risk. Acute symptomatic toxicity was low for participants on tamoxifen or placebo and compliance remained correspondingly high with a predicted 77% of women on tamoxifen and 82% of women on placebo continuing medication at 5 years. There was a significant increase in hot flushes (34 % versus 20 %) mostly in premenopausal women (p < 0.005), vaginal discharge (16% versus 4%, p < 0.005), and menstrual irregularities (14% versus 9%, p < 0.005). The requirements for hormone replacement therapy for women on tamoxifen or placebo were the same. Safety monitoring indicates no adverse anti oestrogenic effects of tamoxifen. There was no obvious effect of tamoxifen on bone mineral densities (single photon radial absorption). The fibrinogen and antithrombin III were both lowered, resulting in no observed detrimental effect on the ratio of these clotting factors. There was a significant reduction in the serum cholesterol maintained out to 5 years. Annual pelvic assessment using transvaginal ultrasound indicates an increased incidence of uterine fibromata and benign ovarian cysts. These results have encouraged the commencement of the NSABP national trial in the USA, and the subsequent start of national trials in Italy and the UK, which together should provide sufficient evidence to evaluate the efficacy of tamoxifen for prevention of breast cancer.
Tamoxifen in breast cancer: Not so easy to write off
Breast, 2008
For the past 30 years, tamoxifen has saved millions of lives throughout the world. The same has been proven in randomized trials and metaanalyses. Recent trials have shown clinical superiority of aromatase inhibitors over tamoxifen in terms of disease free survival and reduction in complications. However, because of the unique mechanism of tamoxifen, intrinsic advantages and low cost, this wonderdrug may still be a reasonable choice for hormonal therapy in breast cancer. r