Olaparib does not cause clinically relevant QT/QTc interval prolongation in patients with advanced solid tumours: results from two phase I studies.

BACKGROUND: Some therapeutic agents in oncology can be causally associated with specific cardiovascular events including QT/QTc interval prolongation. We investigated the effect of multiple dosing of the oral poly (ADP-ribose)-polymerase (PARP) inhibitor, olaparib (tablet formulation) on QT/QTc interval. METHODS: Two phase I, open-label, three-part studies (NCT01921140 [study 4] and NCT01900028 [study 7]) were conducted in adults with refractory/resistant advanced solid tumours. In both studies, parts A and B assessed the QT/QTc interval effects of single-dose oral olaparib 100 (study 4) or 300 (study 7) mg and multiple-dose olaparib 300 mg bid for 5 days, respectively, while part C evaluated continued access to olaparib for additional safety analyses. An ANCOVA model tested the primary objective of multiple-dose effects of olaparib on QT interval corrected using Fridericia's formula (QTcF). RESULTS: Data from 119 and 109 patients were pooled from parts A and B, respectively, for QT/QTc analysis. At pre-dose and up to 12 h post-dose, the upper limits of the 90 % confidence intervals (CIs) for the difference in QTcF least squares means after olaparib multiple dosing versus control (day -1) were <10 ms, suggesting a lack of clinically relevant effect on cardiac repolarization. A slight shortening of QTcF was observed at most time points versus control. QTcF results for the individual studies and single-dose olaparib paralleled the primary multiple-dose pooled analysis, with upper limits of the 90 % CIs < 10 ms. CONCLUSION: Olaparib tablets administered as multiple or single doses had no clinically significant effect on QT/QTc interval.

A good drug made better: the fulvestrant dose-response story.

Sequential use of endocrine therapies remains the cornerstone of treatment for hormone receptor-positive advanced breast cancer, before the use of cytotoxic chemotherapy for unresponsive disease. Fulvestrant is an estrogen receptor (ER) antagonist approved for the treatment of postmenopausal women with ER+ advanced breast cancer after failure of prior antiestrogen therapy. Initially approved at a monthly dose of 250 mg, the recommended fulvestrant dose was revised to 500 mg (500 mg/mo plus 500 mg on day 14 of month 1) after demonstration of improved progression-free survival versus fulvestrant 250 mg. We have reviewed the dose-dependent effects of fulvestrant, both from a retrospective combined analysis of dose-dependent reduction of tumor biomarkers in the presurgical setting (3 previously reported studies: Study 18, Neoadjuvant Endocrine Therapy for Women with Estrogen-Sensitive Tumors, and Trial 57) and from a review of clinical studies for advanced breast cancer in postmenopausal women. Analysis of presurgical data revealed a consistent dose-dependent effect for fulvestrant on tumor biomarkers, with increasing fulvestrant dose resulting in greater reductions in ER, progesterone receptor, and Ki67 labeling index. The dose-dependent biological effect corresponds with the dose-dependent clinical efficacy observed in the treatment of advanced breast cancer after failure of prior antiestrogen therapy. Although it remains to be determined in a phase III trial, cross-trial comparisons suggest a dose-dependent relationship for fulvestrant as first-line treatment for advanced breast cancer. Overall, biological and clinical data demonstrate a strong dose-dependent relationship for fulvestrant, supporting the efficacy benefit seen with fulvestrant 500 mg over the 250 mg dose.

Final overall survival: fulvestrant 500 mg vs 250 mg in the randomized CONFIRM trial.

BACKGROUND: At the time of the initial analysis of overall survival (OS) for the Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) randomized, double-blind, phase III trial, approximately 50% of patients had died. A final analysis of OS was subsequently planned for when 75% of patients had died. METHODS: Patients were randomly assigned 1:1 to fulvestrant 500 mg administered as two 5-mL intramuscular injections on days 0, 14, and 28 and every 28 (±3) days thereafter or fulvestrant 250 mg administered as two 5-mL intramuscular injections (one fulvestrant and one placebo [identical in appearance to study drug]) on days 0, 14 (two placebo injections only), and 28 and every 28 (±3) days thereafter. OS was analyzed using an unadjusted log-rank test. No adjustments were made for multiplicity. Serious adverse events (SAEs) and best response to subsequent therapy were also reported. All statistical tests were two-sided. RESULTS: In total, 736 women (median age = 61.0 years) were randomly assigned to fulvestrant 500 mg (n = 362) or 250 mg (n = 374). At the final survival analysis, 554 of 736 (75.3%) patients had died. Median OS was 26.4 months for fulvestrant 500 mg and 22.3 months for 250 mg (hazard ratio = 0.81; 95% confidence interval = 0.69-0.96; nominal P = .02). There were no clinically important differences in SAE profiles between the treatment groups; no clustering of SAEs could be detected in either treatment group. Type of first subsequent therapy and objective responses to first subsequent therapy were well balanced between the two treatment groups. CONCLUSIONS: In patients with locally advanced or metastatic estrogen receptor-positive breast cancer, fulvestrant 500 mg is associated with a 19% reduction in risk of death and a 4.1-month difference in median OS compared with fulvestrant 250 mg. Fulvestrant 500 mg was well tolerated, and no new safety concerns were identified.

Comparing duration of response and duration of clinical benefit between fulvestrant treatment groups in the CONFIRM trial: application of new methodology.

Comparisons of duration of response (DoR) and duration of clinical benefit (DoCB) within clinical trials are prone to biases. To address these biases, we used new methodology to prospectively analyze expected DoR and expected DoCB. Objective response rate and clinical benefit rate were calculated for fulvestrant 500 and 250 mg, and used to calculate expected DoR and expected DoCB for each dose group. The ratios for expected DoR and expected DoCB (expected DoR500/expected DoR250 and expected DoCB500/expected DoCB250) were then calculated, thereby allowing statistical comparisons of these endpoints between each arm of the COmparisoN of Faslodex In Recurrent or Metastatic breast cancer (CONFIRM) trial. Expected DoRs for fulvestrant 500 and 250 mg were 3.2 and 3.6 months, respectively. The expected DoR ratio between fulvestrant 500 and 250 mg was not statistically significant (0.89; 95 % CI, 0.48-1.67, P = 0.724). The expected DoCBs for fulvestrant 500 and 250 mg were 9.8 and 7.2 months, respectively. The expected DoCB ratio showed that the expected DoCB for fulvestrant 500 mg was significantly improved compared with the expected DoCB for fulvestrant 250 mg (1.36; 95 % CI, 1.07-1.73, P = 0.013). Analysis of the expected DoR and expected DoCB showed fulvestrant 500 mg significantly increased expected DoCB compared with fulvestrant 250 mg in the CONFIRM trial.

Fulvestrant treatment of precocious puberty in girls with McCune-Albright syndrome.

BACKGROUND: McCune-Albright Syndrome (MAS) is usually characterized by the triad of precocious puberty (PP), fibrous dysplasia, and café au lait spots. Previous treatments investigated for PP have included aromatase inhibitors and the estrogen receptor modulator, tamoxifen. Although some agents have been partially effective, the optimal pharmacologic treatment of PP in girls with MAS has not been identified. The objective of this study was to evaluate the safety and efficacy of fulvestrant (FaslodexTM), a pure estrogen receptor antagonist, in girls with progressive precocious puberty (PP) associated with McCune-Albright Syndrome (MAS). METHODS: In this prospective international multicenter trial, thirty girls ≤ 10 years old with MAS and progressive PP received fulvestrant 4 mg/kg via monthly intramuscular injections for 12 months. Changes in vaginal bleeding, rates of bone age advancement, growth velocity, Tanner staging, predicted adult heights, and uterine and ovarian volumes were measured. RESULTS: Median vaginal bleeding days decreased from 12.0 days per year to 1.0 day per year, with a median change in frequency of -3.6 days, (95% confidence interval (CI) -10.10, 0.00; p = 0.0146). Of patients with baseline bleeding, 74% experienced a ≥50% reduction in bleeding, and 35% experienced complete cessation during the study period (95% CI 51.6%, 89.8%; 16.4%, 57.3%, respectively). Average rates of bone age advancement (ΔBA/ΔCA) decreased from 1.99 pre-treatment to 1.06 on treatment (mean change -0.93, 95% CI -1.43, -0.43; p = 0.0007). No significant changes in uterine volumes or other endpoints or serious adverse events occurred. CONCLUSIONS: Fulvestrant was well tolerated and moderately effective in decreasing vaginal bleeding and rates of skeletal maturation in girls with MAS. Longer-term studies aimed at further defining potential benefits and risks of this novel therapeutic approach in girls with MAS are needed. TRIAL REGISTRATION: NCT00278915.

Results of the CONFIRM phase III trial comparing fulvestrant 250 mg with fulvestrant 500 mg in postmenopausal women with estrogen receptor-positive advanced breast cancer.

PURPOSE: We compared fulvestrant 500 mg regimen with the approved dose of fulvestrant 250 mg per month for treatment of postmenopausal women with estrogen receptor-positive advanced breast cancer who experienced progression after prior endocrine therapy. PATIENTS AND METHODS: Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) is a double-blind, parallel-group, multicenter, phase III study. Patients were randomly assigned to fulvestrant 500 mg (500 mg intramuscularly [IM] on day 0, then 500 mg IM on days 14 and 28 and every 28 days thereafter) or 250 mg every 28 days. Primary end point was progression-free survival (PFS). Secondary end points included objective response rate, clinical benefit rate (CBR), duration of clinical benefit (DoCB), overall survival (OS), and quality of life (QOL). RESULTS: PFS was significantly longer for fulvestrant 500 mg (n = 362) than 250 mg (n = 374) (hazard ratio [HR] = 0.80; 95% CI, 0.68 to 0.94; P = .006), corresponding to a 20% reduction in risk of progression. Objective response rate was similar for fulvestrant 500 mg and 250 mg (9.1% v 10.2%, respectively). CBR was 45.6% for fulvestrant 500 mg and 39.6% for fulvestrant 250 mg. DoCB and OS were 16.6 and 25.1 months, respectively, for the 500-mg group, whereas DoCB and OS were 13.9 and 22.8 months, respectively, in the 250-mg group. Fulvestrant 500 mg was well tolerated with no dose-dependent adverse events. QOL was similar for both arms. CONCLUSION: Fulvestrant 500 mg was associated with a statistically significant increase in PFS and not associated with increased toxicity, corresponding to a clinically meaningful improvement in benefit versus risk compared with fulvestrant 250 mg.

Evaluation of fulvestrant in clinical practice: use of an electronic data registry.

BACKGROUND: Most postmenopausal women with hormone receptor-positive advanced breast cancer eventually develop resistance to endocrine therapy, resulting in disease progression and the need for further treatment. Fulvestrant's distinct mode of action offers the potential to overcome tumor resistance to previous endocrine treatments. PATIENTS AND METHODS: This observational, postmarketing, Web-based surveillance study collected "real-world" information on the use of, and the outcomes associated with, fulvestrant 250-mg-per month treatment of patients with advanced breast cancer in clinical practice. RESULTS: A total of 213 postmenopausal patients with advanced breast cancer were enrolled from 34 practices throughout the United States. Of these, 200 patients (93.9%) had received previous endocrine therapy. Overall, 85.4% of patients had received previous aromatase inhibitor treatment for early breast cancer, advanced breast cancer, or both. In clinical practice, fulvestrant was most frequently administered as a second-line (46% of patients) or a third-line endocrine treatment (27.7% of patients) for advanced disease. Most patients who discontinued fulvestrant (55.1%) subsequently received cytotoxic chemotherapy. Fulvestrant treatment resulted in clinical benefit for 47.9% of patients; 58 patients (27.2%) exhibited an objective response, of whom 3 exhibited a complete response. The median time to response was 2.1 months, and the median duration of response was 7.6 months. At the time of analysis, 74.6% of patients had experienced disease progression; median time to progression was 4.7 months. CONCLUSION: These findings are similar to those reported in the clinical trial setting and confirm that fulvestrant has clinical activity after progression on previous endocrine therapy, including aromatase inhibitors.