Study of patritumab deruxtecan versus drug combination in patients with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer

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What is this study about?

This study focuses on treating patients with hormone receptor-positive, HER2-negative breast cancer that has either spread to other parts of the body (metastatic) or cannot be removed by surgery (unresectable locally advanced). The main treatment being tested is patritumab deruxtecan (also known as MK-1022), which will be compared to other standard treatments chosen by doctors, including paclitaxel, capecitabine, doxorubicin, or other similar medications.

The purpose of this research is to determine how well patritumab deruxtecan works compared to standard treatments in controlling the disease and helping patients live longer. The study is designed for patients whose cancer has continued to grow despite previous treatment with hormone therapy and special medications called CDK4/6 inhibitors.

During the study, participants will be randomly assigned to receive either patritumab deruxtecan or one of the standard treatment options. All medications will be given through an intravenous infusion (directly into a vein), except for capecitabine which is taken as tablets by mouth. The treatment will continue as long as it is helping the patient and side effects are manageable.

1 Initial treatment assignment

You will be randomly assigned to receive either patritumab deruxtecan or another treatment chosen by your physician

Your physician will select from available treatments including paclitaxel, capecitabine, doxorubicin, or other approved medications

2 Treatment administration

If assigned to patritumab deruxtecan: You will receive the medication through intravenous infusion

If assigned to physician’s choice treatment: The medication will be given either through intravenous infusion or as oral medication, depending on the selected treatment

Your treatment will continue until your disease progresses or you experience unacceptable side effects

3 Regular monitoring

Your health status will be regularly evaluated using imaging scans to check if the cancer is responding to treatment

Your overall physical condition will be assessed using a standard performance scale

You will complete quality of life questionnaires about your physical functioning, emotional well-being, and pain levels

4 Safety monitoring

Your doctor will monitor you for any side effects throughout the treatment period

Regular health checks will include assessment of any new symptoms or health changes

5 Study duration

The study is planned to continue until July 2033

Your participation will last until your disease progresses or you need to stop treatment for other reasons

Who Can Join the Study?

Must have hormone receptor positive breast cancer that is either locally advanced (cannot be surgically removed) or has spread to other parts of the body (metastatic)
Must have confirmation from a central laboratory that the cancer is:
– HR-positive (responds to hormone therapy)
– HER2-negative (does not have high levels of HER2 protein)
– Has evaluable HER3 (another protein) levels from a recent tissue sample
Must have had cancer progression or return while on previous treatment with:
– CDK4/6 inhibitor (a type of targeted therapy) combined with hormone therapy as first treatment for advanced breast cancer, or
– Disease return during or within 24 months after completing treatment with CDK4/6 inhibitor given with hormone therapy after surgery
Must be suitable for at least one standard treatment option as determined by the doctor
Must have cancer that can be measured using special imaging criteria (RECIST 1.1)
If living with HIV, the infection must be well-controlled with anti-HIV medications
Must be able to perform daily activities independently or with minimal assistance (ECOG performance status of 0 or 1) within 7 days before joining the study
Must be an adult aged 18 years or older

Who Cannot Join the Study?

History of treatment with HER3-targeted therapy (a specific type of cancer treatment targeting HER3 proteins)
Active brain metastases (cancer that has spread to the brain) that are not treated and stable
Significant heart conditions including:
- Heart failure (when heart cannot pump blood effectively)
- Irregular heartbeat that is not controlled by medication
- Heart attack within the past 6 months
Current treatment with other experimental drugs or participation in other clinical trials
Severe liver or kidney problems
Autoimmune conditions (diseases where the immune system attacks healthy cells) requiring systemic treatment
Active infections requiring treatment, including:
- Hepatitis B
- Hepatitis C
- HIV
Known allergies to the study medications or their components
Pregnancy or breastfeeding
Unable to follow study procedures or attend scheduled visits

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country
Centre Hospitalier Regional Et Universitaire De Brest	Brest	France
Institut Gustave Roussy	Villejuif	France
Fondazione Policlinico Universitario Agostino Gemelli IRCCS	Rome	Italy
Medizinische Hochschule Hannover	Hanover	Germany
Szpital Wojewodzki Im. Mikolaja Kopernika W Koszalinie	Koszalin	Poland

Other Sites

Site Name	City	Country
Ospedale San Raffaele S.r.l.	Milan	Italy
Semmelweis University	Budapest	Hungary
Istituto Europeo Di Oncologia S.r.l.	Milan	Italy
IRCCS Istituto Nazionale Tumori Fondazione Pascale	Naples	Italy
Universitätsklinikum des Saarlandes – Homburg/Saar, Klinik für Urologie und Kinderurologie	Homburg	Germany
Wojewodzki Szpital Specjalistyczny Im. Janusza Korczaka W Slupsku Sp. z o.o.	Slupsk	Poland
Lnfzd Gbghhtk Hfmpstbr Ow Azxrjy	Athens	Greece
Hkreradn Ubwzvmzxzuqdc df A Cvciqq	A Coruna Galicia	Spain
Uuqlmmgpylrulcefnwoql Eukhowkx Aav	Erlangen	Germany
Hmvzrphi Cesodu Dp Betmoifmz	Barcelona	Spain
Clrwrng Uutoatlfsxdupxaqlgam Bmnogp Khr	Berlin	Germany
Kotxslgb Cqydgtwp gnmrh	Chemnitz	Germany
Hcsilquh Csfzdzv Srs Csshiv	Madrid	Spain
Aobmfj Mlvuqzq Cmgjfq Spye	Thessaloniki	Greece
Crzqgt Ltor Bvjwgv	Lyon	France
Abnfxlu Ouujzxzyruc Pnqe Gbbbirsx Xvbky	Bergamo	Italy
Knejnhfe Dwzppsrd gtoyy	Dortmund	Germany
Iyjritks fmmw Ktqorfvls Tignxyftrfteeymkvyw uue Ipnuronsuxcs Ukr gdjsg	Ulm	Germany
Usotiqljjfaqylxjbfayu Sblnpaszcxwdxxgdkc Adu	Kiel	Germany
Hqkyxvdx Uhiorunfnsiyp Mxzwgls Dt Vifbdgqrlv	Santander	Spain
Iosmfrmn Chyurv Dcvmtmywpograysfz	L'hospitalet De Llobregat	Spain
Uazsitarsl Grllnqj Hodeparp Oh Hdyslzfqe	Heraklion	Greece
Smhelfe Kqncvzqtr Mbncdfucbbnv Snlnn Whhieaayvkkr I Aphxabglqnqwl Z Wsioqwgnhitdfjczwop Cqftote Opipoquvq W Oovcfzvwd	Olsztyn	Poland
Mwj Mpxnlfw Ccglpx Doxgaaiidqp Gdbi	Duesseldorf	Germany
Fsxxdiqpab Ibarhpuhwd Imxmohdb Nyesjiemkeu Bcvok	Milan	Italy
Cqygno Hpkpf Bqagjzojj	Rouen	France
Oxmtquyc Omrnddvado Isvxcar	Budapest	Hungary
Bwhxjjwaoon Vmqjqipkj Odhkmplkvvvs	Kecskemet	Hungary
Ksoklrja Lidcw Glmk	Detmold	Germany
Asyjlqizup Fnwummsjdct Dtejbicc Ktnrwpge gjelb	Frankfurt	Germany
Utvgwinzuroucksjorddj Mqebbfhjk Ahv	Magdeburg	Germany
Sxwhbhodzfkfdzxavnvdvh Vjpuaxebx Ocpjcbpjdgaq	Nyiregyhaza	Hungary
Hxofyift Uckgjisdkayce Vtdahi Dt Vdpuj	Sevilla	Spain
Nvibwdkj Iultnuss Ouwtijtmc Imt Mhrto Stleookdecvphojbuocdmhmmjfch Irywiiuv Bnfxdaqu	Cracow	Poland
Agknkli Hjqppwfn	Athens	Greece
Siovq Midnou Shp z oxtb Syvb	Lodz	Poland
Ccvuuww Offwgoerj Iki Pvdrz Farewthunj Lvliictmzki W Bvbfqinnfo	Bydgoszcz	Poland
Kabjcggm Muafrdovnx dub Bgoglsyfrncysjy gjyzo	Trier	Germany
Dcaaubjd iq Sskbtzwvrybib gfrja	Siegen	Germany
Bbxqppqwbyfw Ckrzxgd Oajggpxec Imh Mvlrr Synghhyvrxufswjomb W Buhsocuqmwb	Bialystok	Poland
Aaokitogh Helwbpxm	Athens	Greece

Trial status

Country	Status	Recruitment Start
France	Recruiting	02.10.2025
Germany	Recruiting	02.10.2025
Greece	Recruiting	02.10.2025
Hungary	Recruiting	02.10.2025
Italy	Recruiting	02.10.2025
Poland	Not recruiting	02.10.2025
Spain	Recruiting	02.10.2025

Trial locations

Investigated Drugs:

Patritumab deruxtecan (also known as HER3-DXd) is a targeted therapy medication that works by delivering cancer-fighting substances directly to cancer cells that have high levels of a protein called HER3. It’s designed to treat breast cancer cells while minimizing damage to healthy cells.

Treatment of Physician’s Choice (TPC) refers to a standard treatment option where the doctor selects from available approved therapies based on what they believe will work best for the individual patient. This could include various chemotherapy drugs or other approved treatments for breast cancer.

Investigated Diseases:

Hormone receptor positive breast cancer – A type of breast cancer where cancer cells grow in response to the hormones estrogen and/or progesterone. The cancer cells have special proteins called hormone receptors on their surface that attach to hormones in the bloodstream. When hormones bind to these receptors, they stimulate the cancer cells to grow and divide. This is one of the most common types of breast cancer, typically developing slowly over time. The cancer usually begins in the milk ducts or milk-producing glands of the breast tissue and can spread to other parts of the breast.

Trial ID:

2025-520582-51-00

Protocol code:

MK-1022-016

Trial Phase:

Therapeutic confirmatory (Phase III)

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Study of patritumab deruxtecan versus drug combination in patients with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?