Phase 2 Trial of Seribantumab Plus Fulvestrant in Postmenopausal Women With Metastatic Breast Cancer

Official Title

SHERBOC: A Double-blind, Placebo-controlled, Phase 2 Trial of Seribantumab Plus Fulvestrant in Postmenopausal Women With Hormone Receptor-positive, Heregulin Positive (HRG+), HER2 Negative Metastatic Breast Cancer (Merrimack Pharmaceuticals Inc.)


This study is a multi-centre, randomized, double-blind, placebo-controlled, Phase 2 study in postmenopausal women with heregulin positive, hormone receptor positive, HER2 negative metastatic, unresectable breast cancer.

Trial Description

Primary Outcome:

  • Progression Free Survival
Secondary Outcome:
  • Overall Survival
  • Objective Response Rate
  • Time to Progression
  • Rate of treatment-emergent adverse events reported with the combinations of seribantumab plus fulvestrant versus fulvestrant alone
  • Pharmacokinetic (PK) profile of seribantumab when given in combination with fulvestrant and of fulvestrant when given in combination with serbantumab.
This study is a randomized, double-blind, placebo-controlled international phase 2 trial in patients with HRG+, HR+, HER2- metastatic breast cancer that has progressed following treatment with no more than 2 prior therapies, one of which must have been a CDK inhibitor. All patients will be screened for heregulin using central testing, and eligible patients will be randomized to receive either seribantumab + fulvestrant or placebo + fulvestrant. Disease status will be assessed according to RECIST v 1.1 to support the primary endpoint.

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Canadian Cancer Society

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