Silibinin Enhances Anti-PD-1 Efficacy in Brain Metastases of Non-Small Cell Lung Cancer

Research at the Dr. Josep Trueta University Hospital in Catalonia, Spain, has uncovered a promising combination therapy for non-small cell lung cancer (NSCLC) patients with brain metastases (BM). The study, published in Frontiers in Medicine, demonstrates that silibinin, a flavonolignan with known blood-brain barrier permeability and anti-BM activity, can enhance the effectiveness of pembrolizumab, a PD-1 inhibitor, in achieving durable partial responses in BM.

Key Takeaways:

• Silibinin, when combined with pembrolizumab, achieved a durable partial response in BM, lasting over 9 months, in a 72-year-old male patient with stage IVB lung adenocarcinoma and BM.
• The patient initially responded to brain hypofractionated stereotactic radiotherapy and pembrolizumab, but progression occurred with new jejunal metastasis and increasing temporal brain lesion.
• After switching to pembrolizumab with silibinin supplementation, the patient achieved a nearly complete intracranial response with no extracranial progression at 9 months.
• Molecular analysis revealed high PD-L1 expression and a METex14 mutation, potentially enhancing the response to immunotherapy.
• The study suggests that silibinin may target STAT3/TIMP1-driven immunosuppressive astrocytes, overcoming secondary immunoresistance to pembrolizumab in BM.
• Further investigation of the role of silibinin in improving immunotherapy outcomes in advanced lung cancer patients with BM is required.

Statistics:

• 20% of patients with NSCLC are diagnosed with BM, which is associated with poor prognosis (Frontiers in Medicine).
• Pembrolizumab has shown promising results in advanced NSCLC with PD-L1 50%, including patients with BM.
• The patient in the study achieved a durable partial response in BM, lasting over 9 months.
• The study highlights the potential of silibinin as an adjuvant therapy to enhance anti-PD-1 efficacy in BM.

Sources:

• The STAT3/TIMP1 inhibitor silibinin overcomes secondary immunoresistance to pembrolizumab in brain metastases from METex14 skipping mutated non-small cell lung cancer: a case report. Frontiers in Medicine, 2025,12.
• Immunotherapy Weekly. July 23, 2025; p 772.
• NewsRx. Dr. Josep Trueta University Hospital Researchers Discuss Findings in Non-Small Cell Lung Cancer (The STAT3/TIMP1 inhibitor silibinin overcomes secondary immunoresistance to pembrolizumab in brain metastases from METex14 skipping mutated ...).