Hematologic adverse events following palbociclib dose reduction in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer: pooled analysis from randomized phase 2 and 3 studies.
ABSTRACT: BACKGROUND:Palbociclib improves outcomes for women with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer (HR+/HER2- ABC). Dose reductions are recommended for the management of hematologic toxicities. A previous pooled analysis from the PALOMA clinical trials showed that 36.9% of patients required dose reduction, predominantly during the first 6?months of treatment and with decreasing frequency during subsequent 28-day treatment cycles (C). Previous data have shown that palbociclib dose reductions do not affect efficacy. This pooled, post hoc analysis evaluated the frequency of hematologic adverse events (AEs) before and after palbociclib dose reduction in PALOMA-1, PALOMA-2, and PALOMA-3. METHODS:This analysis evaluated the frequency of hematologic AEs 30?days before dose reduction and during each subsequent treatment from C1 to C6 among patients who required palbociclib dose reduction. Data were pooled from 3 randomized studies. PALOMA-1 was a phase 2, open-label study of postmenopausal patients untreated for ABC receiving palbociclib plus letrozole or letrozole alone. PALOMA-2 was a phase 3, double-blind study of postmenopausal patients untreated for ABC receiving palbociclib plus letrozole or placebo plus letrozole. PALOMA-3 was a phase 3, double-blind study of pre/perimenopausal or postmenopausal patients, whose disease progressed on prior endocrine therapy, receiving palbociclib plus fulvestrant or placebo plus fulvestrant. RESULTS:A total of 311 (35.5%) patients with HR+/HER2- ABC required a palbociclib dose reduction (93.6% due to AEs) from 125 to 100?mg. Mean patient age was 59.9?years, and 46.9% of patients had visceral disease. Median time to dose reduction was 70?days. The majority of dose reductions occurred within 3?months of starting palbociclib treatment. Incidences of all-grade and grades 3/4 hematologic AEs were lower following dose reduction. CONCLUSIONS:A decrease in frequency and severity of hematologic AEs, including febrile neutropenia, following palbociclib dose reduction was observed, supporting the recommended use of dose reduction in AE management. TRIAL REGISTRATION:These studies were sponsored by Pfizer. ClinicalTrials.gov: NCT00721409; registration date July 24, 2008. ClinicalTrials.gov: NCT01740427; registration date December 4, 2012. ClinicalTrials.gov: NCT01942135; registration date September 13, 2013.
Project description:BACKGROUND:PALOMA-2 confirmed that first-line palbociclib + letrozole improved progression-free survival (hazard ratio, 0.58; 95% confidence interval, 0.46-0.72) in postmenopausal women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). This analysis evaluated palbociclib-associated hematologic adverse events (AEs) and provides insight on managing these AEs. MATERIALS AND METHODS:Postmenopausal women with ER+/HER2- ABC were randomly assigned 2:1 to letrozole (2.5 mg daily continuously) plus oral palbociclib (125 mg daily; 3 weeks on/1 week off) or placebo. Safety assessments were performed at baseline, days 1 and 15 (first two cycles) and day 1 of subsequent cycles, and included white blood cell, platelet, and absolute neutrophil count (ANC). RESULTS:PALOMA-2 randomized 666 women to palbociclib + letrozole (n = 444) or placebo + letrozole (n = 222). Neutropenia was the most common AE (95.3%) with palbociclib (grade 3, 55.6%; grade 4, 11.5%) and was managed by dose modifications; progression-free survival was similar between patients who experienced grade ? 3 neutropenia versus those who did not. Median (range) time to onset of neutropenia with palbociclib + letrozole was 15 (12-700) days (grade ? 3, 28.0 [12-854] days); median duration of each neutropenia episode grade ? 3 was 7.0 days. Asian ethnicity and low baseline ANC were associated with increased risk of grade 3/4 neutropenia with palbociclib (p < .001). CONCLUSION:Palbociclib + letrozole was generally well tolerated. Neutropenia, the most frequently reported AE in women with ER+/HER2- ABC, was mostly transient and manageable by dose modifications in patients who experienced grade ? 3 neutropenia, without appearing to compromise efficacy. (Pfizer; NCT01740427) IMPLICATIONS FOR PRACTICE: Palbociclib demonstrated an acceptable safety profile in PALOMA-2 in women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) receiving first-line palbociclib + letrozole. Although hematologic adverse events (AEs) are typically expected with anticancer therapies and are often clinically significant, palbociclib-related hematologic AEs, particularly neutropenia (most frequent AE), were transient/manageable by dose reduction, interruption, or cycle delay, which is in contrast to the more profound neutropenia associated with chemotherapy. Palbociclib dose adjustments decreased hematologic AE severity without appearing to compromise efficacy, supporting palbociclib + letrozole as a first-line treatment for ER+/HER2- ABC.
Project description:BACKGROUND:In PALOMA-2, palbociclib-letrozole significantly improved progression-free survival (PFS) vs placebo-letrozole in women with estrogen receptor-positive, human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced breast cancer (ABC) in the first-line setting. We evaluated the efficacy, safety, and pharmacokinetics of palbociclib in Japanese women in PALOMA-2. METHODS:In this phase 3 study, 666 postmenopausal women with ER+/HER2- ABC were randomized 2:1 to palbociclib (125 mg/day [3 weeks on/1 week off]) plus letrozole (2.5 mg daily) or placebo plus letrozole. A prespecified, exploratory, subgroup analysis of Japanese patients (n?=?46) was conducted to compare results with those of the overall population. RESULTS:At the February 26, 2016 cutoff, median PFS among the 46 Japanese patients was 22.2 months (95%CI, 13.6?not estimable) with palbociclib-letrozole vs 13.8 months (5.6?22.2) with placebo-letrozole (hazard ratio, 0.59 [95%CI, 0.26-1.34]). The most common adverse events (AEs) were hematologic and more frequent among Japanese patients than the overall population (neutropenia: 93.8% [87.5% grade 3/4] vs 79.5% [66.4%]; leukopenia: 62.5% [43.8%] vs 39.0% [24.8%]); no Japanese patients had febrile neutropenia. Palbociclib dose reductions due to toxicity (mainly neutropenia) were more common in Japanese patients (62.5% vs 36.0%); few permanently discontinued due to AEs. Although mean palbociclib trough concentration was higher in Japanese patients vs non-Asians (95.4 vs 61.7 ng/mL), the range of individual values of the Japanese patients was within that of non-Asians. CONCLUSIONS:These results from PALOMA-2 suggest that palbociclib-letrozole merits consideration as a first-line treatment option for postmenopausal Japanese patients with ER+/HER2? ABC. ClinicalTrials.gov: NCT01740427.
Project description:<h4>Objective</h4>In the PALOMA-2 trial, palbociclib in combination with letrozole prolonged progression-free survival (PFS) and exhibited an acceptable safety profile in patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer (ABC). This post hoc analysis of PALOMA-2 evaluated the efficacy and safety of palbociclib plus letrozole in patients with preexisting conditions grouped by Medical Dictionary for Regulatory Activities (MedDRA) System Organ Class (SOC).<h4>Methods</h4>Postmenopausal patients without prior treatment for ABC were randomized 2:1 to receive palbociclib (125 mg/d on a 3 weeks on/1 week off schedule) plus letrozole (2.5 mg/d, continuous) or placebo plus letrozole. Patients were grouped by the following MedDRA SOC preexisting conditions: gastrointestinal, musculoskeletal, metabolic, and vascular/cardiac. Median PFS was estimated by the Kaplan-Meier method, and treatment emergent adverse events (AEs) were compared between treatment arms within each preexisting condition subgroup.<h4>Results</h4>At baseline, 276 (41.4 %) patients had preexisting gastrointestinal disorders, 390 (58.6 %) had musculoskeletal disorders, 259 (38.9 %) had metabolic disorders, and 382 (57.4 %) had vascular/cardiac disorders. Baseline characteristics were similar between subgroups and between each arm within subgroups. Regardless of baseline preexisting condition, palbociclib plus letrozole prolonged PFS compared with placebo plus letrozole. Treatment-emergent AEs associated with palbociclib plus letrozole and dose modifications due to AEs were similar across preexisting condition subgroups.<h4>Conclusion</h4>This post hoc analysis of PALOMA-2 demonstrated a favorable effect of palbociclib on PFS and a safety profile consistent with previous observations, regardless of underlying preexisting condition. Pfizer Inc (NCT01740427).
Project description:Background:This report assesses the efficacy and safety of palbociclib plus endocrine therapy (ET) in women with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer (ABC) with or without visceral metastases. Patients and methods:Pre- and postmenopausal women with disease progression following prior ET (PALOMA-3; N?=?521) and postmenopausal women untreated for ABC (PALOMA-2; N?=?666) were randomized 2 : 1 to ET (fulvestrant or letrozole, respectively) plus palbociclib or placebo. Progression-free survival (PFS), safety, and patient-reported quality of life (QoL) were evaluated by prior treatment and visceral involvement. Results:Visceral metastases incidence was higher in patients with prior resistance to ET (58.3%, PALOMA-3) than in patients naive to ET in the ABC setting (48.6%, PALOMA-2). In patients with prior resistance to ET and visceral metastases, median PFS (mPFS) was 9.2?months with palbociclib plus fulvestrant versus 3.4?months with placebo plus fulvestrant [hazard ratio (HR), 0.47; 95% confidence interval (CI), 0.35-0.61], and objective response rate (ORR) was 28.0% versus 6.7%, respectively. In patients with nonvisceral metastases, mPFS was 16.6 versus 7.3?months, HR 0.53; 95% CI 0.36-0.77. In patients with visceral disease and naive to ET in the advanced disease setting, mPFS was 19.3?months with palbociclib plus letrozole versus 12.9?months with placebo plus letrozole (HR 0.63; 95% CI 0.47-0.85); ORR was 55.1% versus 40.0%; in patients with nonvisceral disease, mPFS was not reached with palbociclib plus letrozole versus 16.8?months with placebo plus letrozole (HR 0.50; 95% CI 0.36-0.70). In patients with prior resistance to ET with visceral metastases, palbociclib plus fulvestrant significantly delayed deterioration of QoL versus placebo plus fulvestrant, whereas patient-reported QoL was maintained with palbociclib plus letrozole in patients naive to endocrine-based therapy for ABC. Conclusions:Palbociclib plus ET prolonged mPFS in patients with visceral metastases, increased ORRs, and in patients previously treated for ABC, delayed QoL deterioration, presenting a standard treatment option among patients with visceral metastases amenable to endocrine-based therapy. Clinical trial registration:NCT01942135, NCT01740427.
Project description:BACKGROUND:Palbociclib administered with endocrine therapy was tolerable when the overall incidence of toxicities was assessed separately for three PALOMA studies. This study analyzed pooled, longer-term PALOMA safety data longitudinally. METHODS:Data were pooled from three randomized phase II and III studies (ClinicalTrials.gov: NCT00721409, NCT01740427, NCT01942135) of hormone receptor-positive/human epidermal growth factor receptor 2?negative advanced breast cancer patients. Front-line patients were randomly assigned to receive letrozole with/without palbociclib (PALOMA-1) or letrozole plus palbociclib/placebo (PALOMA-2). In PALOMA-3, patients with prior endocrine resistance received fulvestrant plus palbociclib/placebo. The cumulative event rates of adverse events (AEs), reporting up to 50 months of treatment, were assessed over time. RESULTS:Patients who received endocrine therapy (n = 1343) were included in this pooled analysis (872 were also treated with palbociclib, and 471 were not). The most common AEs with palbociclib plus endocrine therapy were neutropenia and infections (any grade, 80.6% and 54.7%, respectively), which were higher than in the endocrine monotherapy arm (any grade, 5.3% and 36.9%). The most common hematologic AEs (?15.0% in the palbociclib arm) were more likely to be reported in the initial months of the study, after which time the cumulative event rate did not substantially increase. With palbociclib plus endocrine therapy, any grade AEs leading to permanent discontinuation over three years occurred in only 8.3% of patients. CONCLUSIONS:Based on these long-term safety analyses, there is no evidence of specific cumulative or delayed toxicities with palbociclib plus endocrine therapy, supporting the ongoing investigation of palbociclib plus endocrine therapy in early breast cancer (NCT02513394).
Project description:PURPOSE:In PALOMA-2, palbociclib plus letrozole significantly improved progression-free survival (PFS) as initial treatment of estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer. We assessed the benefit of palbociclib plus letrozole in Asians. PATIENTS AND METHODS:Of 666 enrolled postmenopausal women with estrogen receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer (no prior treatment of advanced disease), 95 were Asian. Patients were randomly assigned 2:1 to receive palbociclib plus letrozole or placebo plus letrozole. The primary end point was investigator-assessed PFS. Secondary end points were overall survival, objective response, patient-reported outcomes, pharmacokinetics, and safety. RESULTS:Median PFS was significantly longer in Asian patients who received palbociclib plus letrozole versus placebo plus letrozole (25.7 months [95% CI, 19.2 months to not estimable] v 13.9 months [95% CI, 7.4 to 22.0 months]; hazard ratio, 0.49; 95% CI, 0.27 to 0.87; P = .007). The most common toxicities with palbociclib were hematologic and more frequent among Asians versus non-Asians: neutropenia (any grade, 95.4% v 76.8%; grade 3/4, 89.2% v 62.5%), leukopenia (43.1% v 38.3%; 32.3% v 23.5%), and thrombocytopenia (27.7% v 13.5%; 4.6% v 1.1%). No Asians had febrile neutropenia. Discontinuation rates as a result of adverse events were similar among Asian and non-Asian patients who received palbociclib plus letrozole (10.8% and 9.5%). In Asians, quality of life (QOL) was maintained with no significant differences observed between treatments from baseline in breast cancer-specific QOL and general health status scores. Change from baseline in EuroQol five dimensions index scores was significantly higher with palbociclib plus letrozole (0.013 v -0.069; P = .0132). Geometric mean palbociclib trough concentration values were higher in Asians versus non-Asians (93.8 v 61.7 ng/mL). CONCLUSION:Consistent with the overall study population, the addition of palbociclib to letrozole significantly improved PFS in Asians. Hematologic toxicities were more frequent in Asians versus non-Asians but manageable with early dose modifications while maintaining QOL.
Project description:BACKGROUND:The cyclin-dependent kinase 4/6 (CDK4/6) inhibitor palbociclib, in combination with endocrine therapy (ET), significantly prolonged progression-free survival in women with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer (HR+/HER2- ABC) in PALOMA-2 and PALOMA-3. Neutropenia and palbociclib dose reductions/interruptions occurred more frequently in the Japanese versus overall populations. We evaluated neutropenia patterns, palbociclib dose management, and clinical responses after dose reduction in Japanese patients in PALOMA-2 and PALOMA-3 and a single-arm Japanese phase 2 study. METHODS:PALOMA-2 and the Japanese phase 2 study enrolled postmenopausal women with estrogen receptor-positive, HER2- ABC who had not received prior systemic therapy for advanced disease; PALOMA-3 enrolled women with HR+/HER2- ABC, regardless of menopausal status, whose disease had progressed after prior ET. Palbociclib (125 mg/day) was administered 3 weeks on/1 week off. Dose reduction/interruption, cycle delay, tumor response, and laboratory-assessed neutropenia were analyzed in Japanese patients who received palbociclib. RESULTS:A total of 101 Japanese patients received palbociclib?+?ET. Among Japanese patients in the 3 studies, the frequency of all-grade/grade 3/grade 4 neutropenia was 94%/53%/34%, 100%/69%/21%, and 100%/67%/26%, respectively. Twenty (63%), 28 (67%), and 15 (56%) patients required palbociclib dose reduction. Dose interruption or reduction did not affect palbociclib treatment duration, and durable tumor response was observed despite dose reduction. CONCLUSION:Neutropenia was manageable with dose modifications, without affecting palbociclib treatment duration or efficacy. TRIAL REGISTRATION:Pfizer (NCT01740427, NCT01684215, NCT01942135).
Project description:<h4>Background</h4>Previous studies demonstrated the tolerability of palbociclib plus endocrine therapy (ET). This analysis evaluated safety based on more recent cutoff dates and a longer palbociclib treatment exposure.<h4>Patients and methods</h4>Data were pooled from three randomized studies of patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC), including postmenopausal women who had not received prior systemic treatment for advanced disease (PALOMA-1/-2) and pre- and postmenopausal women who had progressed on prior ET (PALOMA-3).<h4>Results</h4>Updated cutoff dates were December 21, 2017 (PALOMA-1), May 31, 2017 (PALOMA-2), and April 13, 2018 (PALOMA-3). Total person-years of treatment exposure were 1,421.6 with palbociclib plus ET (n = 872) and 528.4 with ET (n = 471). Any-grade neutropenia and infections were more frequent with palbociclib plus ET (82.1% and 59.2%, respectively) than with ET (5.1% and 39.5%). The hazard ratios were 1.6 (p = .0995) for grade 3/4 infections, 1.8 (p = .4358) for grade 3/4 viral infections, 1.4 (p = .0001) for infections, and 30.8 (p < .0001) for neutropenia. Febrile neutropenia was reported in 1.4% of patients receiving palbociclib plus ET. Cumulative incidence of all-grade hematologic adverse events in both arms peaked during the first year of treatment and plateaued over the 5 subsequent years. Interstitial lung disease was reported in 13 patients receiving palbociclib plus ET and 3 receiving ET.<h4>Conclusion</h4>This 5-year, long-term analysis demonstrated that palbociclib plus ET has a consistent and stable safety profile and is a safe treatment for patients with HR+/HER2- ABC.<h4>Implications for practice</h4>Several treatments for patients with breast cancer are associated with long-term or latent adverse events. This long-term, 5-year analysis demonstrated that palbociclib plus endocrine therapy has a consistent and stable safety profile without cumulative or delayed toxicities. These results further support palbociclib plus endocrine therapy as a safe and manageable treatment in clinical practice for patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer.
Project description: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.
Project description:PURPOSE:The selective cyclin-dependent kinase 4/6 inhibitor palbociclib was approved in Argentina in 2015 for postmenopausal women with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC) or metastatic breast cancer (MBC) based on phase III study results. The Ibrance Real World Insights (IRIS) study aims to evaluate palbociclib in patients with HR-positive/HER2-negative ABC or MBC in the real-world setting in multiple countries globally. Here we report results from patients enrolled in the IRIS study in Argentina. PATIENTS AND METHODS:This retrospective medical chart review study included postmenopausal women with confirmed HR-positive/HER2-negative ABC or MBC who were treated with palbociclib plus letrozole as first-line endocrine-based therapy or with palbociclib plus fulvestrant in women with disease progression after endocrine therapy. Participating physicians reviewed medical records of up to six patients each, collecting demographic and clinical data. Outcomes included progression-free and overall survival rates. RESULTS:Records were extracted for 162 patients in Argentina (palbociclib plus letrozole, n = 105 [65%]; palbociclib plus fulvestrant, n = 57 [35%]). The 6-month progression-free survival rate was 94% for patients treated with palbociclib plus letrozole and 95% for patients treated with palbociclib plus fulvestrant; 85% and 80% of patients treated with palbociclib plus letrozole were progression free at 12 and 18 months, respectively. Six-month survival rates were 98% for palbociclib plus letrozole and 98% for palbociclib plus fulvestrant; 93% and 89% of patients treated with palbociclib plus letrozole were alive at 12 and 18 months, respectively. CONCLUSION:Results from this first real-world evaluation of clinical outcomes in Argentina suggest that palbociclib plus letrozole or fulvestrant delivers favorable effectiveness, as measured by progression-free and overall survival rates.