Abstract P6-18-29: Real-world treatment patterns and clinical outcomes with palbociclib combination therapy received in US community oncology practices

Background:

The treatment landscape for women with HR+/HER2- advanced and metastatic breast cancer (A/MBC) is changing as new agents are being combined with more established treatments to achieve greater efficacy in combating resistant and unresponsive disease. The present study is designed to describe patient characteristics, treatment patterns, and clinical outcomes in a cohort of women with HR+/HER2- A/MBC treated with palbociclib plus aromatase inhibitor (P+AI) or palbociclib plus fulvestrant (P+FV) in the US community oncology setting.

Methods:

Retrospective medical record data from adult women diagnosed with HR+/HER2- A/MBC who initiated P+AI or P+FV for treatment of A/MBC on or after February 3, 2015 were collected from the Vector Oncology Data Warehouse, a network comprised of 10 community oncology practices across the US. Descriptive analyses were performed on patient characteristics, treatment patterns, and clinical outcomes. Time to event outcomes (progression-free rate (PFR) and survival rate (SR)) at 12 (PFR-12, SR-12) and 24 (PFR-24, SR-24) months for the P+AI combination as first line endocrine therapy and 12 and 18 months for the P+FV combination as treatment following prior endocrine based therapy in either the adjuvant or metastatic setting.

Results:

Among 304 patients who received palbociclib combination therapy, 281 (92.4%) received it per labeled indication. Of the 281 on-label users, the focus of reporting here, 233 (82.9%) received P+AI as their initial endocrine therapy after A/MBC diagnosis; 48 (17.1%) received P+FV after prior endocrine therapy for breast cancer. Patient mean age (SD) was 63.1 (11.4) and 68.2 (10.2) years for patients receiving P+AI and P+FV, respectively. Patients were predominantly white (74.2% for P+AI and 77.1% for P+FV patients).The initial dosing for palbociclib was 125mg/day in 85.4% (n=199) of P+AI and 79.2% (n=38) of P+FV patients. Among patients who received P+AI, PFR-12 was 69.8% and PFR-24 was 46.8% with median follow up time of 10.8 months and 36.8% of progression events. The SR-12 was 89.8% and SR-24 was 71.4%. For patients who received P+FV, PFR-12 was 43.5% and PFR-18 was 39.9% with a median follow up time of 7.6 months and 50.0% of progression events. The SR-12 was 76.3% and SR-18 was 65.0%.

Conclusions:

This study provides real-world assessment of treatment patterns and clinical outcomes of patients with HR+/ HER2- A/MBC who received palbociclib in combination with an AI or a FV in US community oncology settings. These findings demonstrate the benefit of palbociclib combination therapy in a diverse real world population.

Sponsor: Pfizer, Inc.

Citation Format: Trocio J, Lin J, Fisher MD, Hu N, Davis C, McRoy L, Walker MS, Iyer S. Real-world treatment patterns and clinical outcomes with palbociclib combination therapy received in US community oncology practices [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-29.

Abstract P6-18-27: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Odom D, Mitra D, Hollis K, Richardson D, Kaye JA, McRoy L. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-27.

Real-world evidence analysis of palbociclib prescribing patterns for patients with advanced/metastatic breast cancer treated in community oncology practice in the USA one year post approval

Background

Rapidly evolving understanding of cancer biology has presented novel opportunities to translate that understanding into clinically relevant therapy. Palbociclib, a novel, first-in-class cyclin-dependent kinase (CDK) 4/6 inhibitor was approved in the USA in February 2015 for the treatment of advanced/metastatic breast cancer. We examined real-world evidence in the first year post approval to understand the clinical and demographic characteristics of patients treated with palbociclib in community oncology practices and the dosing, treatment, and complete blood count (CBC) monitoring patterns.

Methods

This was a retrospective observational study of structured data from a US electronic medical record (EMR) database. Female patients receiving palbociclib after 31 January 2015 were followed through 31 March 2016. Our methodological rules were constructed to aggregate drugs received according to the order in which they are given, i.e., identify the line of therapy as first, second, or third line, etc., using treatment order and course description fields from the EMR.

Results

There were 763 patients initiating palbociclib who met the selection criteria. Of those, 612 (80.2%) received palbociclib concomitantly with letrozole. Mean follow up was 6.4 months and mean age at palbociclib initiation was 64 years. Of patients with a known starting dose (n = 417), 79.9% started on palbociclib 125 mg. Dose reductions were observed in 20.1% of patients. Percentages of patients according to line of therapy at initiation of palbociclib were first-line, 39.5%; second-line, 15.7%; third-line, 13.1%; and fourth-line therapy or later, 31.7%. On average, two CBC tests were conducted during the first cycle of palbociclib treatment. Overall, 74.6% of patients had a neutropenic event during follow up including 47.3% and 8.0% of patients with a grade 3 or 4 occurrence, respectively.

Conclusions

Real-world palbociclib use one year post US approval demonstrates a more heterogeneous patient population than that studied in the clinical trials with more than half of the patients receiving palbociclib plus letrozole in later lines of therapy. CBC testing rates suggested good provider compliance with monitoring guidelines in the USA prescribing information. The occurrence of grade 3 and 4 neutropenia (based on laboratory results) was consistent with the rates of grade 3 and 4 neutropenia in two phase-III studies (PALOMA-2, 56% and 10%; PALOMA-3, 55% and 11%, respectively). Understanding palbociclib utilization in real-world patients and how drug dosing and monitoring are performed aids in the understanding of safe and effective use of the drug.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-0958-2) contains supplementary material, which is available to authorized users.

Abstract P3-11-01: Treatment patterns for young women with HR+/HER2- metastatic breast cancer in the United States in the era of CDK 4/6 inhibitors

Background: NCCN guidelines recommend that premenopausal women with HR+/HER2- metastatic breast cancer (MBC) be rendered postmenopausal and then treated accordingly. After its approval in February 2015, the CDK4/6 inhibitor palbociclib (P), in combination with endocrine therapy (ET), has become a standard of care in the first-line or pretreated settings for women with HR+/HER2- MBC. Specialty pharmacy prescription data indicate that 12% of all women with HR+/HER2- MBC treated with P in the United States are younger than 50 years of age. We assessed the real world treatment patterns and outcomes before and after approval of P in women with HR+/HER2- MBC. We further sought to assess the impact of the NCCN guidelines for premenopausal women on treatment patterns and outcomes.

Methods: This retrospective cohort study utilized electronic health record (EHR) data from Flatiron Health (Fl) from 1/2012 through 4/2017 to evaluate patient characteristics and first-line ET treatment patterns among women with HR+/HER2- MBC prior to and after P approval. Menopausal status was defined by age (< 50 vs >50 yrs). Additional datasets of > 13,000 pts with MBC in the Truven Health MarketScan and Optum Clinformatics claims and Humedica EHR databases will be included to represent a more comprehensive dataset and evaluate clinical outcomes.

Results and Discussion: Initial results include 4,537 pts in the FI database who initiated a first-line ET regimen. Overall, 30% of pts < 50 yrs used P compared to 29% of women age >50. Treatment patterns for initial endocrine therapy are shown in the table.

Initial Endocrine Therapy Women <_50 yrs N (%) women > 50 yrs N(%) cohort01.2012-01.201502.2015-04.2017Absolute Change01.2012-01.201502.2015-04.2017Absolute ChangeN (%)296 (%0273 (100%) 2062 (100%)1906 (100%) ET monotx +/- LHRH296 (100%)192 (70%)-30%2062 (100%)1345 (71%)-29%TAM108 (36%)75 (27%)-9%161 (8%)78 (4%)-4%AI139 (47%)80 (29%)-18%1326 (64%)866 (45%)-19%FUL49 (17%)37 (14%)-3%575 (28%)401 (21%)-7%ET + P +/- LHRHNA81 (30%)+30%NA561 (29%)+29%% of concurrent LHRH77 (26%)92 (34%)+8%20 (1%)28 (1%)0%

Decreased use of tamoxifen as 1st line ET was observed in pts <_50 yrs over the observed time. 47% of young pts initiated endocrine based treatment with AI monotherapy in the pre-P era, consistent with the NCCN guidelines. About 26% (pre-P) and 34% (post-P) of pts ≤50 yrs initiated first ET with ovarian suppression in the analyzed treatment eras. The concurrent use of LHRH increased 8%.

Conclusions: The treatment paradigm for women with HR+/HER2- MBC has evolved over the last >5 years. Consistent with NCCN guidelines, more young pts are receiving ovarian suppression as part of initial therapy, and pts regardless of age are receiving treatment with P. There has been a related decrease in use of tamoxifen for younger pts and overall. These data illustrate rapid incorporation of palbociclib into standard care for US pts with HR+/HER2- MBC. Further treatment patterns and therapy outcome data for these groups reflecting real world use ET regimens of over 17,000 pts in the combined cohort, will be reported.

Citation Format: Burstein HJ, Mayer EL, DeMichele A, Harnett J, Mardekian J, McRoy L, Huang Bartlett C, Koehler M, Fahed Rimawi M. Treatment patterns for young women with HR+/HER2- metastatic breast cancer in the United States in the era of CDK 4/6 inhibitors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-11-01.

Abstract P5-21-24: Retrospective assessment of treatment patterns and outcomes associated with palbociclib plus letrozole for postmenopausal women with HR+/HER2– advanced breast cancer enrolled in an early access program

Background: The objective of this study was to evaluate treatment patterns and clinical outcomes among patients who received palbociclib in combination with letrozole (P+L) for the treatment of HR+/HER2–advanced breast cancer (ABC) as part of an Expanded Access Program (EAP) in the United States.

Methods: Data were obtained by a retrospective chart review of patients previously enrolled in the EAP. Complete data from time of initial diagnosis of ABC until the date of chart abstraction (end of follow-up), including the post-EAP period, were obtained. Clinical outcomes assessed included clinical benefit rate (CBR), defined as complete response, partial response, or stable disease for ≥24 weeks from P + L initiation, progression free survival (PFS) and overall survival (OS). Survival outcomes were assessed using the Kaplan-Meier statistical analysis.

Results: Data from 126 patients were included in this analysis. Median age was 62.5 years at EAP enrollment, and a majority of patients were Caucasian (83%). Approximately 25% of patients had de novo metastatic disease. A majority of patients had a performance status of ECOG 0 (56%) or 1 (37%) at EAP enrollment. Visceral disease was present in 71% of patients and 16% had bone-only disease. The majority of patients in this cohort from the EAP were heavily pre-treated, having had up to 5 prior lines of therapy in the metastatic setting prior to initiating P + L therapy; nearly 59% received 3+ prior lines before initiating P + L. Only 11% of patients received P + L as their initial regimen for MBC. At the time of the last available record, 12 patients were still on P + L therapy, an average of 21 months after the start of the EAP program. Nearly 80% of patients had prior AI exposure and 69% had prior chemotherapy. CBR was 33% for the overall sample of patients treated with P + L and 22% in those with 3+ prior lines of treatment. Patients with prior AI exposure in the ABC setting (n=100) had a CBR of 27% while those without prior AI exposure had CBR of 58%. Patients with prior chemotherapy (n=87) had a CBR of 28% and those without prior chemotherapy had CBR of 46%. For the entire cohort, 6- and 12-month PFS rates were 40% and 25% respectively; 12- and 24-month OS rates were 66% and 44%, respectively. Patients receiving 3+ lines of prior therapy had 6- and 12-month PFS rates of 28% and 19%, respectively, and 12- and 24-month OS rates of 59% and 34% respectively.

Conclusions: Our results suggest that the majority of patients enrolled in the EAP program derived benefit from receiving treatment with P + L despite multiple prior lines of treatment and prior endocrine-based therapy, including prior AI. These findings further demonstrate the benefit of treatment with palbociclib combination therapy in HR+/HER2– MBC.

Citation Format: Brufsky A, Davis K, Mitra D, Nagar S, McRoy L, Cotter M, Stearns V. Retrospective assessment of treatment patterns and outcomes associated with palbociclib plus letrozole for postmenopausal women with HR+/HER2– advanced breast cancer enrolled in an early access program [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-24.

Abstract P6-16-05: Early utilization pattern of palbociclib 1 year post-approval in the United States

Background

Palbociclib was approved in the U.S. in February 2015 for the treatment of advanced/metastatic breast cancer (MBC) in combination with letrozole as initial endocrine based therapy for post-menopausal women with ER+/HER2- disease. We examined the demographic, clinical characteristics and treatment patterns of patients initiating palbociclib (PAL) + letrozole (LET) in real-world, community oncology practices.

Methods

This was a retrospective observational study of female breast cancer patients identified in the Navigating Cancer (NC) EMR database. The NC database collects EMR data, in both structured and unstructured fields (patient/clinical progress notes), from over 975 oncology and hematology providers across more than 50 locations in 25 states. Female patients with record of treatment with PAL after 01/31/2015 were selected. Combination treatment with LET was defined as having a record for LET within 30 days of the PAL prescription. Line of therapy (LOT) was assessed from the date of metastatic diagnosis and assigned by evaluating treatment plans pre-and post PAL initiation. Bi-monthly cohorts were constructed based on the month of initiation of PAL from 02/01/2015-01/31/2016. Interim results are presented; data from an additional three months of follow-up (through 03/31/2016) are pending.

Results

Overall, 931 unique patients were identified as having initiated PAL treatment. Of those, 608 (65.3%) received PAL + LET. Mean follow-up was relatively short at 5.4 mo (SD=3.5). Confirmed ER+/HER2- was observed in 71.6% of patients and 50.3% were age ≥65, mean age was 64.3 yrs. Of patients with available ECOG-PS at treatment initiation (n=424): 0/1=78.5%, 2=17.5% and 3=4.0%. Of patients with a known starting dose (n=418), 69.9% initiated with PAL 125mg, 22.0% at 100mg and 8.1% at 75mg. Compared to women < 65, women ≥ 65 were more often started with 100mg (25.4% vs. 18.9%) and 75mg (10.0% vs 6.5%). Any dose reductions were observed in 20.6% of patients (21.5% of patients receiving 125mg). During the year following approval, 39.8% of patients initiated PAL + LET at LOT1, 15.6% at LOT2, 13.0% at LOT3 and 31.6% at LOT4+, following MBC diagnosis. Over time the proportion of late use (LOT4+) declined from 39.7% in Feb/Mar '15 to 23.9% in Dec '15/Jan '16 with more patients utilizing in LOT3 (from 7.9% in Feb/Mar '15 to 19.5% in Dec '15/Jan '16).

Number of Patients Initiating PAL + LET by LOT and Month. AllFeb/Mar '15Apr/May '15Jun/Jul '15Aug/Sep '15Oct/Nov '15Dec'15/Jan '16N (%)608(100)63(10.4)108(17.8)125(20.6)108(17.8)91(14.5)113(18.6)LOT1 (%)242(39.8)23(36.5)45(41.7)53(42.4)45(41.7)33(36.3)43(38.1)LOT2 (%)95(15.6)10(15.9)12(11.1)19(15.2)15(13.9)18(19.8)21(18.6)LOT3 (%)79(13.0)5(7.9)10(9.3)18(14.4)12(11.1)12(13.2)22(19.5)LOT4+ (%)192(31.6)25(39.7)41(38.0)35(28.0)36(33.3)28(30.8)27(23.9)

Conclusions

There was a trend toward earlier utilization of PAL + LET from Feb-Jul '15, an increase in later use during Aug/Sep '15, and a return towards earlier use in subsequent cohorts reaching the lowest proportion of LOT 4+ use observed in Dec '15/Jan '16. After a mean follow-up of 5.4 mo, 21.5% of patients receiving the 125 mg dose had a dose reduction. Final results, with additional follow-up, will be presented at conference.

Citation Format: Kish JK, Ward MA, Garofalo D, Ahmed HV, McRoy L, Laney J, Zanotti G, Yu H-T, Feinberg BA. Early utilization pattern of palbociclib 1 year post-approval in the United States [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-16-05.