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OncoMatch/Clinical Trials/NCT06665178

Genomic and Transcriptomic Predictors of Sequential SG Sensitivity After T-DXd in ER+/HER2-Low Metastatic Breast Cancer

Is NCT06665178 recruiting? Yes, currently enrolling (May 2026). This Phase 2 trial studies Sacituzumab Govitecan for breast cancer.

Phase 2RecruitingBritish Columbia Cancer AgencyNCT06665178Data as of May 2026

Treatment: Sacituzumab GovitecanAdvanced hormone positive (HR+), HER2 negative breast cancer continues to pose a challenge when patients have progressed on CDK4/6 inhibitor and endocrine therapy leaving limited treatment options. Antibody-drug conjugates (ADCs) such as sacituzumab govitecan (SG) and trastuzumab deruxtecan (T-DXd) have changed practice due to significant improvement in progression free survival (PFS) and overall survival (OS) seen in this disease setting. There is a genuine interest to use SG sequentially after T-DXd, however there is no current prospectively curated evidence to support this strategy. Though the epitope is different, the payload are both topoisomerase I inhibitors. Thus, evidence is needed of both clinical efficacy and identification of mechanisms of sensitivity and resistance to sequential ADCs in HER-2 low MBC. It is hypothesized that performing whole genome and whole transcriptome sequencing in fresh tumour biopsies post progression of T-DXd and prior to SG in ER+/HER2 low metastatic breast cancer (MBC) will provide mechanistic insights into identifying biomarkers, and thus patients, sensitive to sequential SG.

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Extracted eligibility criteria

Cancer type

Breast Carcinoma

Biomarker criteria

Required: ESR1 overexpression (ER+)

ER+/HER2 low (defined as IHC 1+ or 2+ but FISH or CISH negative by ratio as per ASCO/CAP guidelines)

Required: HER2 (ERBB2) low expression (IHC 1+ or 2+, FISH or CISH negative) (IHC 1+ or 2+, FISH or CISH negative)

HER2 low (defined as IHC 1+ or 2+ but FISH or CISH negative by ratio as per ASCO/CAP guidelines)

Disease stage

Metastatic disease required

Patients with locally advanced or metastatic ER+/HER2 low...breast cancer. Patients with imaging confirmed inoperable locally advanced breast cancer for which treatment is palliative in intent are also permitted.

Performance status

ECOG 0–2(Ambulatory, capable of self-care)

Prior therapy

Min 2 prior lines

Must have received: endocrine therapy — metastatic

Prior treatment must have included prior endocrine based treatment in the metastatic setting in conjunction with a CDK4/6 inhibitor.

Must have received: CDK4/6 inhibitor — metastatic

Prior treatment must have included prior endocrine based treatment in the metastatic setting in conjunction with a CDK4/6 inhibitor.

Must have received: chemotherapy

Prior treatment must include at least 1 line of chemotherapy which must include trastuzumab deruxtecan (T-DXd) as the immediate prior line of therapy prior to study enrollment

Must have received: antibody-drug conjugate (trastuzumab deruxtecan)

Prior treatment must include at least 1 line of chemotherapy which must include trastuzumab deruxtecan (T-DXd) as the immediate prior line of therapy prior to study enrollment

Lab requirements

Blood counts

Absolute neutrophil count ≥1.0 x 10^9/L; Platelets ≥100 x 10^9/L; Hemoglobin ≥9.0 g/dL; INR ≤1.5

Kidney function

Serum creatinine clearance >50 mL/min

Liver function

In absence of liver metastases, direct bilirubin ≤1.5 x ULN, ALT and AST should be below ≤2.5 x ULN. If the patient has liver metastases, ALT and AST should be < 5.0 x ULN.

Acceptable bone marrow and organ function defined by the following laboratory values: Absolute neutrophil count ≥1.0 x 10^9/L; Platelets ≥100 x 10^9/L; Hemoglobin ≥9.0 g/dL; INR ≤1.5; Serum creatinine clearance >50 mL/min; In absence of liver metastases, direct bilirubin ≤1.5 x ULN, ALT and AST should be below ≤2.5 x ULN. If the patient has liver metastases, ALT and AST should be < 5.0 x ULN.

Structured fields extracted by AI. May contain errors — verify against the official protocol.

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