Dongrui R. Lu

BACKGROUND: A phase 2 study showed that progression-free survival was longer with palbociclib plus letrozole than with letrozole alone in the initial treatment of postmenopausal women with estrogen-receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. We performed a phase 3 study that was designed to confirm and expand the efficacy and safety data for palbociclib plus letrozole for this indication. METHODS: In this double-blind study, we randomly assigned, in a 2:1 ratio, 666 postmenopausal women with ER-positive, HER2-negative breast cancer, who had not had prior treatment for advanced disease, to receive palbociclib plus letrozole or placebo plus letrozole. The primary end point was progression-free survival, as assessed by the investigators; secondary end points were overall survival, objective response, clinical benefit response, patient-reported outcomes, pharmacokinetic effects, and safety. RESULTS: The median progression-free survival was 24.8 months (95% confidence interval [CI], 22.1 to not estimable) in the palbociclib-letrozole group, as compared with 14.5 months (95% CI, 12.9 to 17.1) in the placebo-letrozole group (hazard ratio for disease progression or death, 0.58; 95% CI, 0.46 to 0.72; P<0.001). The most common grade 3 or 4 adverse events were neutropenia (occurring in 66.4% of the patients in the palbociclib-letrozole group vs. 1.4% in the placebo-letrozole group), leukopenia (24.8% vs. 0%), anemia (5.4% vs. 1.8%), and fatigue (1.8% vs. 0.5%). Febrile neutropenia was reported in 1.8% of patients in the palbociclib-letrozole group and in none of the patients in the placebo-letrozole group. Permanent discontinuation of any study treatment as a result of adverse events occurred in 43 patients (9.7%) in the palbociclib-letrozole group and in 13 patients (5.9%) in the placebo-letrozole group. CONCLUSIONS: Among patients with previously untreated ER-positive, HER2-negative advanced breast cancer, palbociclib combined with letrozole resulted in significantly longer progression-free survival than that with letrozole alone, although the rates of myelotoxic effects were higher with palbociclib-letrozole. (Funded by Pfizer; PALOMA-2 ClinicalTrials.gov number, NCT01740427 .).

BACKGROUND: The multitargeted tyrosine kinase inhibitor sunitinib has shown activity against pancreatic neuroendocrine tumors in preclinical models and phase 1 and 2 trials. METHODS: We conducted a multinational, randomized, double-blind, placebo-controlled phase 3 trial of sunitinib in patients with advanced, well-differentiated pancreatic neuroendocrine tumors. All patients had Response Evaluation Criteria in Solid Tumors-defined disease progression documented within 12 months before baseline. A total of 171 patients were randomly assigned (in a 1:1 ratio) to receive best supportive care with either sunitinib at a dose of 37.5 mg per day or placebo. The primary end point was progression-free survival; secondary end points included the objective response rate, overall survival, and safety. RESULTS: The study was discontinued early, after the independent data and safety monitoring committee observed more serious adverse events and deaths in the placebo group as well as a difference in progression-free survival favoring sunitinib. Median progression-free survival was 11.4 months in the sunitinib group as compared with 5.5 months in the placebo group (hazard ratio for progression or death, 0.42; 95% confidence interval [CI], 0.26 to 0.66; P<0.001). A Cox proportional-hazards analysis of progression-free survival according to baseline characteristics favored sunitinib in all subgroups studied. The objective response rate was 9.3% in the sunitinib group versus 0% in the placebo group. At the data cutoff point, 9 deaths were reported in the sunitinib group (10%) versus 21 deaths in the placebo group (25%) (hazard ratio for death, 0.41; 95% CI, 0.19 to 0.89; P=0.02). The most frequent adverse events in the sunitinib group were diarrhea, nausea, vomiting, asthenia, and fatigue. CONCLUSIONS: Continuous daily administration of sunitinib at a dose of 37.5 mg improved progression-free survival, overall survival, and the objective response rate as compared with placebo among patients with advanced pancreatic neuroendocrine tumors. (Funded by Pfizer; ClinicalTrials.gov number, NCT00428597.).

BACKGROUND: Hypertension (HTN) is an on-target effect of the vascular endothelial growth factor pathway inhibitor, sunitinib. We evaluated the association of sunitinib-induced HTN with antitumor efficacy and HTN-associated adverse events in patients with metastatic renal cell carcinoma. METHODS: This retrospective analysis included pooled efficacy (n = 544) and safety (n = 4917) data from four studies of patients with metastatic renal cell carcinoma who were treated with sunitinib 50 mg/d administered on a 4-week-on 2-week-off schedule (schedule 4/2). Blood pressure (BP) was measured in the clinic on days 1 and 28 of each 6-week cycle. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier methods; hazard ratios (HRs) for survival were also estimated by a Cox proportional hazards models using HTN as a time-dependent covariate. Efficacy outcomes were compared between patients with and without HTN (maximum systolic BP [SBP] ≥140 mm Hg or diastolic BP [DBP] ≥90 mm Hg). Adverse events were also compared between patients with and without HTN (mean SBP ≥140 mm Hg or mean DBP ≥90 mm Hg). All P values were two-sided. RESULTS: Patients with metastatic renal cell carcinoma and sunitinib-induced HTN defined by maximum SBP had better outcomes than those without treatment-induced HTN (objective response rate: 54.8% vs 8.7%; median PFS: 12.5 months, 95% confidence interval [CI] = 10.9 to 13.7 vs 2.5 months, 95% CI = 2.3 to 3.8 months; and OS: 30.9 months, 95% CI = 27.9 to 33.7 vs 7.2 months, 95% CI = 5.6 to 10.7 months; P < .001 for all). Similar results were obtained when comparing patients with vs without sunitinib-induced HTN defined by maximum DBP. In a Cox proportional hazards model using HTN as a time-dependent covariate, PFS (HR of disease progression or death = .603, 95% CI = .451 to .805; P < .001) and OS (HR of death = .332, 95% CI = .252 to .436; P < .001) were improved in patients with treatment-induced HTN defined by maximum SBP; OS (HR of death = .585, 95% CI = .463 to .740; P < .001) was improved in patients with treatment-induced HTN defined by maximum DBP, but PFS was not. Few any-cause cardiovascular, cerebrovascular, ocular, and renal adverse events were observed. Rates of adverse events were similar between patients with and without HTN defined by mean SBP; however, hypertensive patients had somewhat more renal adverse events (5% vs 3%; P = .013). CONCLUSIONS: In patients with metastatic renal cell carcinoma, sunitinib-associated HTN is associated with improved clinical outcomes without clinically significant increases in HTN-associated adverse events, supporting its viability as an efficacy biomarker.

PURPOSE: In the initial PALOMA-2 (NCT01740427) analysis with median follow-up of 23 months, palbociclib plus letrozole significantly prolonged progression-free survival (PFS) in women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) [hazard ratio (HR) 0.58; P < 0.001]. Herein, we report results overall and by subgroups with extended follow-up. METHODS: In this double-blind, phase 3 study, post-menopausal women with ER+/HER2- ABC who had not received prior systemic therapy for their advanced disease were randomized 2:1 to palbociclib-letrozole or placebo-letrozole. Endpoints include investigator-assessed PFS (primary), safety, and patient-reported outcomes (PROs). RESULTS: After a median follow-up of approximately 38 months, median PFS was 27.6 months for palbociclib-letrozole (n = 444) and 14.5 months for placebo-letrozole (n = 222) (HR 0.563; 1-sided P < 0.0001). All subgroups benefited from palbociclib treatment. The improvement of PFS with palbociclib-letrozole was maintained in the next 2 subsequent lines of therapy and delayed the use of chemotherapy (40.4 vs. 29.9 months for palbociclib-letrozole vs. placebo-letrozole). Safety data were consistent with the known profile. Patients' quality of life was maintained. CONCLUSIONS: With approximately 15 months of additional follow-up, palbociclib plus letrozole continued to demonstrate improved PFS compared with placebo plus letrozole in the overall population and across all patient subgroups, while the safety profile remained favorable and quality of life was maintained. These data confirm that palbociclib-letrozole should be considered the standard of care for first-line therapy in patients with ER+/HER2- ABC, including those with low disease burden or long disease-free interval. Sponsored by Pfizer; ClinicalTrials.gov: NCT01740427.

PURPOSE: This international phase III trial (Investigating Torisel As Second-Line Therapy [INTORSECT]) compared the efficacy of temsirolimus (mammalian target of rapamycin inhibitor) and sorafenib (vascular endothelial growth factor receptor [VEGFR] tyrosine kinase inhibitor) as second-line therapy in patients with metastatic renal cell carcinoma (mRCC) after disease progression on sunitinib. PATIENTS AND METHODS: In total, 512 patients were randomly assigned 1:1 to receive intravenous temsirolimus 25 mg once weekly (n = 259) or oral sorafenib 400 mg twice per day (n = 253), with stratification according to duration of prior sunitinib therapy (≤ or > 180 days), prognostic risk, histology (clear cell or non-clear cell), and nephrectomy status. The primary end point was progression-free survival (PFS) by independent review committee assessment. Safety, objective response rate (ORR), and overall survival (OS) were secondary end points. RESULTS: Primary analysis revealed no significant difference between treatment arms for PFS (stratified hazard ratio [HR], 0.87; 95% CI, 0.71 to 1.07; two-sided P = .19) or ORR. Median PFS in the temsirolimus and sorafenib arms were 4.3 and 3.9 months, respectively. There was a significant OS difference in favor of sorafenib (stratified HR, 1.31; 95% CI, 1.05 to 1.63; two-sided P = .01). Median OS in the temsirolimus and sorafenib arms was 12.3 and 16.6 months, respectively. Safety profiles of both agents were consistent with previous studies. CONCLUSION: In patients with mRCC and progression on sunitinib, second-line temsirolimus did not demonstrate a PFS advantage compared with sorafenib. The longer OS observed with sorafenib suggests sequenced VEGFR inhibition may benefit patients with mRCC.