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GB491+ Fulvestrant

Genor Biopharma Co., Ltd. · Phase 3 active Small molecule

GB491 is a selective estrogen receptor degrader (SERD) that works synergistically with fulvestrant to degrade estrogen receptors and block estrogen signaling in hormone receptor-positive breast cancer cells.

GB491 is a selective estrogen receptor degrader (SERD) that works synergistically with fulvestrant to degrade estrogen receptors and block estrogen signaling in hormone receptor-positive breast cancer cells. Used for Hormone receptor-positive, HER2-negative metastatic breast cancer (in combination with fulvestrant).

At a glance

Generic nameGB491+ Fulvestrant
Also known astest drug + Fulvestrant
SponsorGenor Biopharma Co., Ltd.
Drug classSelective Estrogen Receptor Degrader (SERD)
TargetEstrogen Receptor (ER)
ModalitySmall molecule
Therapeutic areaOncology
PhasePhase 3

Mechanism of action

GB491 is a novel SERD that enhances the activity of fulvestrant, a known estrogen receptor antagonist and degrader. The combination targets estrogen receptor-positive breast cancer by promoting receptor degradation and preventing estrogen-driven proliferation. This dual mechanism aims to overcome resistance to standard endocrine therapies.

Approved indications

Common side effects

Key clinical trials

Primary sources

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SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results