The Efficacy and Safety of Narlumosbart in Combination With Stereotactic Body Radiation Therapy to Improve the Efficacy of First-line Chemotherapy Combined With Immunotherapy in Patients With Bone Metastases From Advanced Non-small Cell Lung Cancer

Summary

Introduction: Immunotherapy in combination with chemotherapy have been recommended as the first-line treatment of driver-negative advanced non-small cell lung cancer (NSCLC), but the efficacy is worse in NSCLC patients with bone metastases due to the immunosuppressive microenvironment. Studies have shown that not only the nuclear factor kappa-B ligand (RANKL) inhibitors but also Stereotactic Body Radiation Therapy (SBRT) play a significant role in improving the tumor immune microenvironment. Therefore, narlumosbart，a monoclonal antibody (mAb) targeting RANKL，in combination with SBRT may have synergistic effects and improve efficacy of immunotherapy and chemotherapy in driver-negative advanced NSCLC patients with bone metastases.

Methods: This single-arm, single-center phase II clinical trial will enroll NSCLC patients with bone metastases who have not received any systemic therapy. Patients will receive narlumosbart and bone target lesion SBRT in combination with first-line treatment immunotherapy and chemotherapy after screening eligible subjects. Narlumosbart, 120mg/time, subcutaneous injection, will be administered every 4 weeks. For the treatment of SBRT for bone metastases, the dose of 24Gy/3F is used for spinal metastases, and 30Gy/5F or 35Gy/5F is used for non-spinal lesions. Chemotherapy combined with immune checkpoint inhibitor therapy will be used in accordance with the guidelines. The primary endpoint is to assess the objective response rate of NSCLC patients with bone metastases from narlumosbart combined with SBRT and first-line chemotherapy and immunotherapy. The secondary endpoints include safety and tolerability, progression-free survival, overall survival, bone-related events, pain score, and quality of life. Sample size was calculated using the Simon's Two-Stage method. 9 patients will be enrolled in the first stage. If ≥ 2 patients achieve CR/PR, the second stage of enrollment will be performed. If fewer than 2 patients achieve CR/PR, the trial will be terminated. In the second phase, 15 patients will be enrolled. 27 subjects will be enrolled in this project, considering the dropout rate of 10%.

Wangjun Yan AND Zhengfei Zhu are the Co-Principal Investigators of this study.

Conditions

• NSCLC
• Stereotactic Body Radiation Therapy (SBRT)
• Immunotherapy

Interventions

DRUG

Narlumosbart

Narlumosbart is a fully humanized anti-RANKL monoclonal antibody (IgG4) with Fab arms identical to denosumab, demonstrating rapid and sustained suppression of bone resorption biomarkers in patients with bone metastases. It will be administered subcutaneously at 120 mg every 4 weeks. Calcium and vitamin D supplementation will be given concurrently to prevent hypocalcemia. Adverse events will be recorded and graded according to CTCAE v5.0. For jaw osteonecrosis, all patients will undergo a mandatory dental examination within 14 days before the first dose, with 3-monthly dental checks during treatment; suspected cases will be managed with oral surgeon consultation. Serum calcium will be monitored at baseline and prior to each dose (every 4 weeks). Corrected calcium \<2.0 mmol/L will be managed with oral calcium (500-1000 mg/day) and vitamin D (400-800 IU/day). Severe hypocalcaemia (\<1.8 mmol/L or symptomatic) will be treated with intravenous calcium gluconate.

RADIATION

Stereotactic Body Radiation Therapy

SBRT will be delivered within one week before the first chemo-immunotherapy cycle. All patients undergo contrast-enhanced CT simulation (1-1.5 mm slice thickness); MRI fusion (T1/T2/STIR) is mandatory for spinal metastases. Target delineation: GTV = visible tumor on CT/MRI; CTV = involved vertebral body sector(s) per ISRC guidelines for spinal lesions, or GTV + 3-5 mm margin for non-spinal lesions; PTV = CTV + 1-2 mm margin. Dose prescription: 24 Gy in 3 fractions for spinal metastases; 30-35 Gy in 5 fractions for non-spinal lesions. Treatment plans use VMAT or IMRT. Daily cone-beam CT (CBCT) is performed before each fraction for image guidance; 6-degree-of-freedom couch corrections are used for spinal lesions. Respiratory motion management (e.g., 4D-CT, gating) is applied for mobile lesions if motion exceeds 5 mm. Patient-specific quality assurance (PSQA) is performed before the first fraction, with gamma analysis (3%/2 mm criteria and ≥95% passing rate) required.

Sponsors & Collaborators

• Fudan University

  lead OTHER

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-02-15

Primary Completion

2026-12-30

Completion

2028-12-30

Countries

• China

Study Locations