Breast cancer drug showdown: which CDK4/6 inhibitor works best?

NCT ID NCT05207709

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This phase 3 trial aimed to compare two drugs, ribociclib and palbociclib, in people with a specific type of advanced breast cancer (HR+/HER2- with HER2-enriched features). Participants received one of the drugs combined with hormone therapy. The goal was to see which combination better delays cancer growth. The study was terminated early and enrolled only 61 of the planned 456 participants, so the findings are limited.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

Ribociclib and palbociclib (both combined with hormone therapy)

What this could lead to

If ribociclib proves better, it could become the preferred treatment for this type of advanced breast cancer, potentially delaying disease progression.

What could go wrong

The trial was terminated early with only 61 participants, so results are limited and may not be conclusive. Both drugs are already approved, so any advantage may be modest.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

basal-like breast carcinoma breast carcinoma breast neoplasm hormone receptor-positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Baptist Memorial Health Care

    Oxford, Mississippi, 38655, United States

  • Bon Secours Memorial Regional Medical Center

    Mechanicsville, Virginia, 231136, United States

  • Carle Cancer Center

    Urbana, Illinois, 61801, United States

  • Centro Hospitalar Vila Nova de Gaia

    Vila Nova de Gaia, 4434-502, Portugal

  • Centro Integral Oncológico Clara Campal (CIOCC)

    Madrid, 28050, Spain

  • Complejo Asistencial Universitario de León

    León, León, 24001, Spain

  • Complejo Hospitalario San Pedro de Alcántara

    Cáceres, 10003, Spain

  • Dana Faber Cancer Institute

    Boston, Massachusetts, 02215, United States

  • Dayton Clinical Oncology

    Kettering, Ohio, 45429, United States

  • Edwards Comprehensive Cancer Center

    Huntington, Virginia, 25701, United States

  • Fundación Jiménez Díaz

    Madrid, Madrid, 28040, Spain

  • H. Clínico San Cecilio de Granada

    Granada, 18016, Spain

  • Hospital Beatriz Ângelo

    Loures, 2674-514, Portugal

  • Hospital Clinic de Barcelona

    Barcelona, 08036, Spain

  • Hospital Clinico Universitario de Valencia

    Valencia, 46010, Spain

  • Hospital Clínico Universitario Lozano Blesa

    Zaragoza, Zaragoza, 50009, Spain

  • Hospital Clínico Universitario de A Coruña

    A Coruña, La Coruña, 15006, Spain

  • Hospital Clínico Universitario de Santiago CHUS

    Santiago de Compostela, La Coruña, 15706, Spain

  • Hospital General Universitario de Alicante

    Alicante, 03010, Spain

  • Hospital General de Catalunya

    Sant Cugat del Vallès, Barcelona, 08195, Spain

  • Hospital La Paz

    Madrid, Madrid, 28046, Spain

  • Hospital Quiron Salud Sagrado Corazon Sevilla

    Seville, Sevilla, 41013, Spain

  • Hospital Sant Joan de Reus

    Reus, 43204, Spain

  • Hospital Senhora da Oliveira - Guimarães

    Creixomil, Portugal

  • Hospital Son Llàtzer

    Palma de Mallorca, Balearic Islands, 07198, Spain

  • Hospital Universitari Arnau de Vilanova de Lleida

    Lleida, 25198, Spain

  • Hospital Universitario 12 de Octubre

    Madrid, 28041, Spain

  • Hospital Universitario La Princesa

    Madrid, 28006, Spain

  • Hospital Universitario Marqués de Valdecilla

    Santander, 39008, Spain

  • Hospital Universitario Morales Meseguer

    Murcia, Murcia, 30008, Spain

  • Hospital Universitario Puerta de Hierro de Majadahonda

    Madrid, 28222, Spain

  • Hospital Universitario Ramón y Cajal

    Madrid, Madrid, 28034, Spain

  • Hospital Universitario Virgen de la Arrixaca

    El Palmar, Murcia, 30120, Spain

  • Hospital Universitario Virgen de las Nieves

    Granada, 18014, Spain

  • Hospital Universitario Virgen del Rocio

    Seville, Sevilla, 41013, Spain

  • Hospital Universitario de Canarias

    Santa Cruz de Tenerife, Canary Islands, 38320, Spain

  • Hospital Universitario de Fuenlabrada

    Fuenlabrada, Madrid, 28942, Spain

  • Hospital Universitario de Gran Canaria Doctor Negrin

    Las Palmas, 35010, Spain

  • Hospital Universitario de Salamanca

    Salamanca, 37007, Spain

  • Hospital Virgen de la Macarena

    Seville, 41007, Spain

  • Hospital Virgen de la Victoria

    Málaga, 29010, Spain

  • Hospital de Basurto

    Bilbao, 48013, Spain

  • Hospital del Mar

    Barcelona, Barcelona, 08003, Spain

  • IOB-Institute of Oncology. Hospital Quironsalud Barcelona

    Barcelona, Barcelona, 8023, Spain

  • IPO Lisboa

    Lisbon, 1500-650, Portugal

  • Institut Català d' Oncologia (ICO Badalona)

    Badalona, Barcelona, 08916, Spain

  • Institut Català d' Oncologia de Girona (ICO Girona)

    Girona, Girona, 17007, Spain

  • Institut Català d'Oncologia (ICO Hospitalet)

    L'Hospitalet de Llobregat, Barcelona, 08908, Spain

  • Instituto Portugues de Oncologia de Porto Francisco Gentil, EPE

    Porto, 4200-072, Portugal

  • Instituto Valenciano de Oncología (IVO)

    Valencia, 46009, Spain

  • Legacy Good Samaritan Hospital and Medical Cente

    Portland, Oregon, 97210, United States

  • Memorial Regional Hospital

    Hollywood, Florida, 33021, United States

  • Montefiore

    The Bronx, New York, 10467, United States

  • Morton Plant Hospital

    Clearwater, Florida, 33756, United States

  • Mount Sinai Florida

    Miami, Florida, 33140, United States

  • NHOH

    Londonderry, New Hampshire, 03053, United States

  • Nevada Cancer Research Foundation

    Las Vegas, Nevada, 89121, United States

  • Northwestern

    Chicago, Illinois, 60611, United States

  • Nothwell Health

    New York, New York, 11042-1069, United States

  • Novant Health Care

    Winston-Salem, North Carolina, 27103, United States

  • Ohio State University Comprehensive Cancer Center

    Columbus, Ohio, 43210, United States

  • Providence Portland Medical Center

    Portland, Oregon, 97225, United States

  • Sinai of Baltimore

    Baltimore, Maryland, 21215, United States

  • The Medical University of South Carolina

    Charleston, South Carolina, 29425, United States

  • University of Kentucky, Markey Cancer Center

    Lexington, Kentucky, 40536, United States

  • University of Miami

    Coral Gables, Florida, 33124, United States

  • University of Nebraska Medical Center

    Omaha, Nebraska, 68198, United States

  • University of North Carolina Lineberger

    Chapel Hill, North Carolina, 27514, United States

  • Unv. Wisconsin

    Madison, Wisconsin, 53792, United States

  • Upstate Carolina Medical Center

    Spartanburg, South Carolina, 29302, United States

  • Vall d´Hebron University Hospital

    Barcelona, 08035, Spain