A Study of Patritumab Deruxtecan (HER3-DXd) in Combination With Trastuzumab Deruxtecan (T-DXd) in Participants With HR-Positive, HER2-Low or HER2-Ultralow Unresectable or Metastatic Breast Cancer

← catalyst calendar

NCT07701941 · readout in 1,595 d

Sponsored by Daiichi Sankyo (industry) · 4568.T — their whole pipeline →. With Merck Sharp & Dohme LLC.

Phase

Phase 1/2

Status

Not yet recruiting

Study type

Interventional

Design

Randomized · None · Treatment

Enrollment

220estimated

Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →

Source: ClinicalTrials.gov, retrieved 2026-08-19

Dates

each axis at the precision it was filed, with the registry's own basis

Date

Filed

Basis

What it is

Start

2026-08-03

estimated

When the study began enrolling

Primary completion

2031-01-01

estimated

The date the last participant is measured for the primary outcome — the readout window

Study completion

2032-05-01

estimated

The whole study's end, after follow-up

First posted

2026-07-14

actual

When this record first appeared on the registry

Results posted

—

When the sponsor posted results to the registry

Record updated

2026-07-14

actual

The sponsor's own last edit to this record — every projection above is as current as this date

What it studies

Conditions

Hormone Receptor Positive
HER2-low or HER2-ultralow
Unresectable or Metastatic Breast Cancer

Interventions

Drug: Patritumab deruxtecan — also filed as U31402, HER3-DXd
Drug: Trastuzumab deruxtecan — also filed as DS8201a, T-DXd

Primary outcomes

what the primary-completion date above is the date OF

Part 1: Number of Participants With at Least One Treatment-emergent Adverse Event (TEAE) and Serious Adverse Event (SAE)

measured Up to approximately 4.5 years

Part 2: Objective Response Per Response Evaluation Criteria in Solid Tumours Version 1.1 (RECIST v.1.1) as Assessed by the Investigator

measured Up to approximately 4.5 years

Permalink · 4568.T's whole pipeline · Catalyst calendar · Every registered study · What changed