Neoadjuvant SBRT Followed by Nab-Paclitaxel Combined With Toripalimab in HR+/HER2- Breast Cancer

Summary

The goal of this clinical trial is to evaluate the efficacy and safety of neoadjuvant radiotherapy followed by chemotherapy combined with immunotherapy in patients with previously untreated stage IIB-IIIC (cT3N0 or cT2-4N1-3) HR-positive and HER2-negative breast cancer. 27 enrolled patients will be assigned to receive stereotactic body radiotherapy followed by Nab-Paclitaxel combined with Toripalimab. The main question it aims th answer is that whether the combination therapy of radiotherapy, de-escalated chemotherapy, and immunotherapy could improve the pCR rate of HR-positive and HER2-negative breast cancer.

Conditions

• Breast Cancer

Interventions

RADIATION

Stereotactic Body Radiation Therapy (SBRT)

The prescribed dose of radiation is 24 Gy delivered in 3 fractions (8 Gy/fraction) using SBRT technique. Subjects received SBRT for the primary breast cancer lesion at 8Gy/Fraction each time for 3 consecutive days, 1 week before the start of systemic therapy. The first day of radiation is C1D1.

DRUG

Toripalimab

Toripalimab will be administered at a fixed dose of 240 mg via intravenous infusion every 3 weeks (q3w). The first dose is given on Cycle 2 Day 1 (C2D1), followed by dosing on the first day of each subsequent cycle for a total of 4 cycles. (Toripalimab×4 240mg D1 q3w)

DRUG

Neoadjuvant Chemotherapy

Combined with Toripalimab, Nab-paclitaxel will be dosed at 125 mg/m² based on body surface area, administered by intravenous infusion weekly (Days 1, 8, 15 of each 21-day cycle) for 4 cycles.(T×4, Nab-Paclitaxel 125mg/m2，D1、D8、D15 q3w).

PROCEDURE

Surgery

Surgery will be performed 2-6 weeks after completion of neoadjuvant therapy. The surgical approach will be determined by the investigator based on disease status and patient preference.

DRUG

Adjuvant Chemotherapy

The anthracycline may be either Epirubicin (body surface area-adjusted 50 mg/m²) or Liposomal Doxorubicin (body surface area-adjusted 30 mg/m²) combined with Cyclophosphamide (body surface area-adjusted 600 mg/m²). Both drugs were administered intravenously every 3 weeks, and then the first day of each course was administered for 4 cycles. (EC×4, Epirubicin 50 mg/m² or Liposomal Doxorubicin 30 mg/m², comined with Cyclophosphamide 600 mg/m², D1, q3w)

RADIATION

Adjuvant Radiotherapy

Conventional radiotherapy will be delivered to the breast/chest wall and regional lymph nodes (investigator-selected technique), with explicit prohibition of tumor bed boost irradiation.

DRUG

Endocrine therapy

Investigator-selected adjuvant endocrine therapy will be deterimend according to applicable guidelines, considering menopausal status, recurrence risk, treatment history, comorbidities as well as patient preference.

Sponsors & Collaborators

• Xijing Hospital

  lead OTHER

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-06-05

Primary Completion

2026-04-30

Completion

2030-12-31

Countries

• China

Study Locations