Spatially Fractionated Radiotherapy With Tislelizumab and Chemotherapy for Bulky Stage III NSCLC: A Phase II Trial

Summary

This is a prospective, single-arm, multicenter phase II clinical study evaluating the efficacy and safety of spatially fractionated radiotherapy (SFRT) combined with tislelizumab and platinum-based doublet chemotherapy as induction/conversion therapy for patients with potentially resectable stage III non-small cell lung cancer (NSCLC) with bulky disease (primary tumor \>5 cm).

SFRT, also known as lattice radiation therapy, is a novel radiotherapy technique that creates alternating high-dose and low-dose regions within the tumor. This approach not only reduces tumor burden but also may enhance anti-tumor immune responses, potentially working synergistically with immunotherapy.

Study participants will receive SFRT to the primary lung tumor (GTV 20 Gy/5 fractions, GTV-Lattice 60 Gy/5 fractions), followed by 2-4 cycles of tislelizumab (200 mg, Q3W) combined with platinum-based doublet chemotherapy. Surgery will be performed 4-6 weeks after the last cycle of neoadjuvant therapy. The first 6 enrolled patients will undergo dose-limiting toxicity (DLT) assessment within 21 days after the first dose of study drug.

The primary endpoint is major pathological response (MPR) rate, defined as the proportion of patients with ≤10% viable tumor cells in the resected specimen. Secondary endpoints include 1-year event-free survival (EFS), pathological complete response (pCR) rate, objective response rate (ORR), disease control rate (DCR), R0 resection rate, 1-year overall survival (OS), time to distant metastasis (TTDM), and safety.

A total of 44 patients will be enrolled across multiple centers in China. An interim analysis will be conducted after 50% of patients are enrolled.

Conditions

• Non-Small Cell Lung Cancer

Interventions

RADIATION

Spatially Fractionated Radiotherapy (SFRT)

Participants receive lattice radiation therapy to the primary lung tumor. The gross tumor volume (GTV) is delineated, and lattice target volumes (GTV-Lattice) are generated using a hexagonal close-packed model within the tumor. Volumetric modulated arc therapy (VMAT) plans are designed. Prescription dose: GTV receives 20 Gy in 5 fractions, and GTV-Lattice receives 60 Gy in 5 fractions. After plan verification, treatment is delivered on 3 non-consecutive working days (e.g., Monday, Wednesday, Friday).

DRUG

Tislelizumab

200 mg administered via intravenous infusion on Day 1 of each 21-day cycle (Q3W) for 2 to 4 cycles, starting on Day 8-15 following SFRT.

DRUG

Carboplatin

AUC 5 administered via intravenous infusion on Day 1 of each 21-day cycle (Q3W) for 2 to 4 cycles. Used in combination with either pemetrexed (for non-squamous histology) or paclitaxel (for squamous histology), at the investigator's discretion.

DRUG

Cisplatin

75 mg/m² administered via intravenous infusion on Day 1 of each 21-day cycle (Q3W) for 2 to 4 cycles. Used in combination with either pemetrexed (for non-squamous histology) or paclitaxel (for squamous histology), at the investigator's discretion. Adequate hydration and antiemetic prophylaxis are required.

DRUG

Pemetrexed

500 mg/m² administered via intravenous infusion on Day 1 of each 21-day cycle (Q3W) for 2 to 4 cycles. Indicated only for patients with non-squamous NSCLC. Vitamin B12 and folic acid supplementation are required per standard practice.

DRUG

Paclitaxel

175 mg/m² administered via intravenous infusion on Day 1 of each 21-day cycle (Q3W) for 2 to 4 cycles. Indicated only for patients with squamous NSCLC. Premedication to prevent hypersensitivity is required per standard practice.

PROCEDURE

Radical Lung Resection Surgery

Definitive radical surgery is performed 4 to 6 weeks (±7 days) after the last dose of neoadjuvant therapy. Surgical approaches include minimally invasive techniques (video-assisted thoracoscopic surgery \[VATS\] or robotic-assisted surgery) or open thoracotomy. Procedures include lobectomy, bilobectomy, pneumonectomy, or sleeve resection, combined with ipsilateral systematic mediastinal lymph node dissection.

Sponsors & Collaborators

• Sichuan Cancer Hospital and Research Institute

  lead OTHER

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-08-20

Primary Completion

2030-06-30

Completion

2030-06-30

Countries

• China

Study Locations