<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-04-13T14:05:00Z</responseDate><request verb="GetRecord" identifier="oai:www.recercat.cat:11351/13499" metadataPrefix="marc">https://recercat.cat/oai/request</request><GetRecord><record><header><identifier>oai:recercat.cat:11351/13499</identifier><datestamp>2025-09-30T02:07:43Z</datestamp><setSpec>com_2072_378070</setSpec><setSpec>com_2072_378040</setSpec><setSpec>col_2072_378092</setSpec></header><metadata><record xmlns="http://www.loc.gov/MARC21/slim" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">
   <leader>00925njm 22002777a 4500</leader>
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      <subfield code="a">Pérez-García, José Manuel</subfield>
      <subfield code="e">author</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="720">
      <subfield code="a">Gil Gil, Miguel J.</subfield>
      <subfield code="e">author</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="720">
      <subfield code="a">Ruiz-Borrego, Manuel</subfield>
      <subfield code="e">author</subfield>
   </datafield>
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      <subfield code="a">Llombart Cussac, Antonio</subfield>
      <subfield code="e">author</subfield>
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   <datafield ind2=" " ind1=" " tag="720">
      <subfield code="a">Bellet Ezquerra, Meritxell</subfield>
      <subfield code="e">author</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="720">
      <subfield code="a">dalenc, florence</subfield>
      <subfield code="e">author</subfield>
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   <datafield ind2=" " ind1=" " tag="260">
      <subfield code="c">2025-08-07T06:27:39Z</subfield>
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   <datafield ind2=" " ind1=" " tag="260">
      <subfield code="c">2025-08-07T06:27:39Z</subfield>
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   <datafield ind2=" " ind1=" " tag="260">
      <subfield code="c">2025-07</subfield>
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   <datafield ind2=" " ind1=" " tag="520">
      <subfield code="a">Advanced breast cancer; Extended overall survival; Hormone receptor positive/HER2 negative</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="520">
      <subfield code="a">Cáncer de mama avanzado; Supervivencia global prolongada; Receptor hormonal positivo/HER2 negativo</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="520">
      <subfield code="a">Càncer de mama avançat; Supervivència global prolongada; Receptor hormonal positiu/HER2 negatiu</subfield>
   </datafield>
   <datafield ind2=" " ind1=" " tag="520">
      <subfield code="a">Background&#xd;
Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) are the mainstay for hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC). While the approved CDK4/6i have demonstrated significant improvements in progression-free survival (PFS), inconsistencies exist for overall survival (OS) benefits. Here, we report updated efficacy results from PARSIFAL, a randomized phase II study, that evaluated first-line palbociclib with either letrozole or fulvestrant in postmenopausal patients with endocrine-sensitive, HR-positive/HER2-negative ABC.&#xd;
Patients and methods&#xd;
PARSIFAL-LONG was an international, multicenter, observational study that extended follow-up for patients included in PARSIFAL. The primary objective evaluated updated OS of palbociclib combined with endocrine therapy (fulvestrant or letrozole). Secondary objectives included updated investigator-assessed PFS and subsequent antineoplastic therapies. Exploratory endpoints included identification of new clinical prognostic markers for OS, specifically PFS duration.&#xd;
Results&#xd;
A total of 419 of 486 (86.2%) patients from PARSIFAL were included. Median follow-up was 7.3 years (interquartile range 6.7-7.7 years). At data cut-off (8 January 2024), no differences in efficacy were observed between fulvestrant and letrozole for OS (hazard ratio 1.01, 95% confidence interval [CI], 0.80-1.28, P = 0.927) or PFS (hazard ratio 1.06,95% CI, 0.85-1.31, P = 0.612). Median OS for the overall PARSIFAL-LONG population was 61.8 months (95% CI 56.5-68.4 months), representing the highest OS reported to date for palbociclib and aligning with outcomes observed for other CDK4/6i in this setting. Median PFS was 32.6 months (95% CI 27.5-38.1 months). A total of 85 (20.3%) patients were defined as early progressors (PFS ≤ 12 months). These patients had a shorter median post-progression OS than patients who remained progression free at 12 months (18.7 versus 27.4 months; hazard ratio 0.65, P = 0.004).&#xd;
Conclusions&#xd;
Extended analysis from PARSIFAL confirmed no difference between fulvestrant and letrozole when combined with palbociclib for patients with endocrine-sensitive, HR-positive/HER2-negative ABC. Efficacy results were consistent with those reported in the pivotal first-line trials involving CDK4/6i. Progression within the first year on CDK4/6i may indicate a poorer prognosis.</subfield>
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   <datafield ind2=" " ind1=" " tag="520">
      <subfield code="a">This work was supported by Pfizer S.L.U (Madrid, Spain) (no grant number). Fulvestrant was provided by AstraZeneca.</subfield>
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      <subfield code="a">http://hdl.handle.net/11351/13499</subfield>
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   <datafield tag="653" ind2=" " ind1=" ">
      <subfield code="a">Mama - Càncer - Tractament</subfield>
   </datafield>
   <datafield tag="653" ind2=" " ind1=" ">
      <subfield code="a">Quimioteràpia combinada</subfield>
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      <subfield code="a">Proteïnes quinases - Inhibidors - Ús terapèutic</subfield>
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      <subfield code="a">DISEASES::Neoplasms::Neoplasms by Site::Breast Neoplasms</subfield>
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      <subfield code="a">Other subheadings::Other subheadings::Other subheadings::/drug therapy</subfield>
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      <subfield code="a">ANALYTICAL, DIAGNOSTIC AND THERAPEUTIC TECHNIQUES, AND EQUIPMENT::Therapeutics::Therapeutics::Drug Therapy::Antineoplastic Protocols::Therapeutics::Drug Therapy::Antineoplastic Combined Chemotherapy Protocols</subfield>
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      <subfield code="a">CHEMICALS AND DRUGS::Chemical Actions and Uses::Pharmacologic Actions::Molecular Mechanisms of Pharmacological Action::Enzyme Inhibitors::Protein Kinase Inhibitors</subfield>
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      <subfield code="a">ENFERMEDADES::neoplasias::neoplasias por localización::neoplasias de la mama</subfield>
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      <subfield code="a">Otros calificadores::Otros calificadores::Otros calificadores::/farmacoterapia</subfield>
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      <subfield code="a">TÉCNICAS Y EQUIPOS ANALÍTICOS, DIAGNÓSTICOS Y TERAPÉUTICOS::terapéutica::terapéutica::farmacoterapia::protocolos antineoplásicos::terapéutica::farmacoterapia::protocolos de quimioterapia antineoplásica combinada</subfield>
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      <subfield code="a">COMPUESTOS QUÍMICOS Y DROGAS::acciones y usos químicos::acciones farmacológicas::mecanismos moleculares de acción farmacológica::inhibidores enzimáticos::inhibidores de proteínas cinasas</subfield>
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      <subfield code="a">Extended follow-up of palbociclib with fulvestrant or letrozole for endocrine-sensitive, hormone receptor-positive/HER2-negative advanced breast cancer in the PARSIFAL trial</subfield>
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