Evaluation of cardiovascular ischemic event rates in dasatinib-treated patients using standardized incidence ratios.

With high survival rates for chronic myeloid leukemia (CML) patients treated with BCR-ABL1 tyrosine kinase inhibitors (TKIs), emerging consequences, such as arterial ischemic events, require consideration when evaluating treatment options. Cardiovascular ischemic event incidence in clinical trials was evaluated in 2712 dasatinib-treated patients with Philadelphia chromosome-positive (Ph+) leukemias from 11 first- and second-line trials (pooled), newly diagnosed CML patients treated with dasatinib or imatinib (DASISION), and prostate cancer patients treated with dasatinib or placebo plus docetaxel/prednisone (READY). Overall, 2-4% of dasatinib-treated patients had cardiovascular ischemic events. Most dasatinib-treated patients with an event had a history of and/or risk factor for atherosclerosis (pooled 77 with history/risk and event/96 with events; DASISION 8/10; READY 15/18). Most cardiovascular ischemic events occurred within 1 year of initiating dasatinib (pooled 69/96; DASISION 7/10; READY 16/18). Comparison of observed and expected event rates through standardized incidence ratios indicates that dasatinib does not increase risk for cardiovascular ischemic events compared with external reference populations.

Lack of uniformity in cardiac assessment during trastuzumab therapy.

Adjuvant therapy with trastuzumab is standard in women with early stage HER-2-positive breast cancer. Following reports of left ventricular (LV) dysfunction with trastuzumab in metastatic disease, trials of adjuvant trastuzumab specified LV monitoring schedules. This study analyzes the pattern of cardiac testing and the incidence of heart failure (HF) in women treated with adjuvant trastuzumab in a real-world setting. De-identified medical and pharmacy claims data for women <65 years of age who began trastuzumab therapy between January 1, 2007 and December 31, 2007 were obtained from an integrated database at Medco Health Solutions, Inc. Patients receiving trastuzumab for ≥90 days were assessed for compliance with standard LV testing, defined as testing at baseline, at 4-month intervals, and at the end of trastuzumab therapy. Cardiac risk factors and HF were identified by ICD-9-CM diagnosis codes, by medical claims, and by pharmacy claims for drugs used to treat diabetes, hypercholesterolemia, or HF. A total of 631 women received trastuzumab ≥30 days, and 585 continued for ≥90 days (median duration 356 days [±1Q = 322-378]). Seventy nine patients had no LV tests. Ninety three were fully compliant with baseline, interval, and final testing. Seven women were identified as having new-onset HF. In this retrospective analysis, clinicians did not routinely follow LV testing protocols used in clinical trials or published recommendations. As breast cancer specific survival rates improve, the long-term contribution of cardiotoxic therapies to cardiac morbidity and mortality in survivors will gain attention. Early efforts to ensure compliance with testing could contribute to use of preventive therapies to mitigate future long-term consequences.

A comparative study of exemestane versus anastrozole in patients with postmenopausal breast cancer with visceral metastases.

PURPOSE: Patients developing visceral breast cancer metastases generally receive chemotherapy rather than endocrine therapy. Recent aromatase inhibitor studies have reported activity in such patients; therefore, this study formally evaluated anastrozole and exemestane in postmenopausal patients in this setting. PATIENTS AND METHODS: Postmenopausal women with advanced breast cancer and > or = 1 visceral (liver or lung) lesion were randomized to anastrozole (1 mg/day orally) or exemestane (25 mg/day orally) for > or = 8 weeks. The primary endpoint was objective response in visceral lesions based on modified Response Evaluation Criteria in Solid Tumors. Secondary endpoints included clinical benefit (objective response plus stable disease > or = 180 days), overall survival, and adverse events. RESULTS: A total of 130 patients were enrolled, and 128 patients (64 anastrozole, 64 exemestane) were included in the intent-to-treat analysis. Accrual delays caused study closure before the target enrollment (N = 200) was reached, limiting the statistical power of the study. Objective response in visceral sites was approximately 15% in both groups. Clinical benefit in visceral sites was 32% of the patients treated with anastrozole and 38% of the patients treated with exemestane. Median survival was 33.3 months and 30.5 months in the anastrozole and exemestane groups, respectively. Toxicities were similar to those previously reported; however, treatment-related adverse events were more frequent with anastrozole (41%) than with exemestane (31%). Both treatments were generally well tolerated in patients with postmenopausal breast cancer with visceral metastases. CONCLUSION: Efficacy was similar in both treatment groups for all endpoints. Aromatase inhibitors can be considered as a treatment option in postmenopausal patients with hormone receptor-positive visceral breast cancer metastases.

Effects of steroidal and nonsteroidal aromatase inhibitors on markers of bone turnover in healthy postmenopausal women.

INTRODUCTION: In contrast to nonsteroidal aromatase inhibitors, the steroidal aromatase inactivator exemestane does not have detrimental effects on bone in animal models. This study was designed to compare the effects of exemestane with the nonsteroidal aromatase inhibitors anastrozole and letrozole on serum and urine levels of biomarkers of bone turnover in healthy postmenopausal women. METHODS: Changes in the concentrations of bone-turnover markers, estrogens, and lipids were assessed after daily administration of exemestane (25 mg), letrozole (2.5 mg), anastrozole (1 mg), or placebo for 24 weeks in healthy postmenopausal women. The primary end point was the percentage change from baseline in bone-turnover-marker levels at week 24. The baseline-adjusted area under the curve (AUC) for weeks 0-12 and 0-24 was calculated to evaluate changes in bone turnover over time, rather than at discrete time points. RESULTS: Seventy-four (88%) of 84 randomized subjects were evaluable for bone-marker assays. Reductions in plasma estrogen levels and increases in bone-resorption markers were comparable for each aromatase inhibitor. Uniquely, exemestane consistently increased the percentage change from baseline in the level of serum procollagen type I N-terminal propeptide (PINP), a marker of bone formation, at week 24. In the active-treatment groups, the baseline-adjusted AUC at weeks 0-12 and 0-24 for PINP was significantly greater for exemestane than the other aromatase inhibitors. CONCLUSION: Exemestane increased serum levels of the bone-formation marker PINP after 24 weeks, suggesting a specific bone-formation effect related to its androgenic structure. Potential effects on cortical bone and reduced fracture risk must be verified in a comparative clinical trial.

Association between prescription co-payment amount and compliance with adjuvant hormonal therapy in women with early-stage breast cancer.

PURPOSE: Noncompliance with adjuvant hormonal therapy among women with breast cancer is common. Little is known about the impact of financial factors, such as co-payments, on noncompliance. PATIENTS AND METHODS: We conducted a retrospective cohort study by using the pharmacy and medical claims database at Medco Health Solutions. Women older than age 50 years who were taking aromatase inhibitors (AIs) for resected breast cancer with two or more mail-order prescriptions, from January 1, 2007, to December 31, 2008, were identified. Patients who were eligible for Medicare were analyzed separately. Nonpersistence was defined as a prescription supply gap of more than 45 days without subsequent refill. Nonadherence was defined as a medication possession ratio less than 80% of eligible days. RESULTS: Of 8110 women younger than age 65 years, 1721 (21.1%) were nonpersistent and 863 (10.6%) were nonadherent. Among 14,050 women age 65 years or older, 3476 (24.7%) were nonpersistent and 1248 (8.9%) were nonadherent. In a multivariate analysis, nonpersistence (ever/never) in both age groups was associated with older age, having a non-oncologist write the prescription, and having a higher number of other prescriptions. Compared with a co-payment of less than $30, a co-payment of $30 to $89.99 for a 90-day prescription was associated with less persistence in women age 65 years or older (odds ratio [OR], 0.69; 95% CI, 0.62 to 0.75) but not among women younger than age 65, although a co-payment of more than $90 was associated with less persistence both in women younger than age 65 (OR, 0.82; 95% CI, 0.72 to 0.94) and those age 65 years or older (OR, 0.72; 95% CI, 0.65 to 0.80). Similar results were seen with nonadherence. CONCLUSION: We found that higher prescription co-payments were associated with both nonpersistence and nonadherence to AIs. This relationship was stronger in older women. Because noncompliance is associated with worse outcomes, future policy efforts should be directed toward interventions that would help patients with financial difficulties obtain life-saving medications.