Andrea Facciabene

Enhancing outcomes in medically inoperable early-stage NSCLC with gut-targeted antibiotics and stereotactic body radiotherapy: results from a randomized pilot study

Background Gut microbiota modulation is an emerging strategy to improve cancer therapy outcomes. This study evaluated the safety and therapeutic potential of combining oral vancomycin—a non-absorbed, gut-restricted antibiotic with primary activity against gram-positive bacteria—with stereotactic body radiotherapy (SBRT) in early-stage non-small cell lung cancer (NSCLC). The underlying hypothesis was that vancomycin-induced changes in gut microbiota could enhance the antitumor effects of SBRT. Methods We conducted a randomized, open-label pilot study in patients with early-stage NSCLC. Patients received oral vancomycin (125 mg, four times daily for 5 weeks, starting 1 week prior to SBRT). Safety, progression-free survival (PFS), overall survival (OS), gut microbiota composition, gut metabolome, and immune responses were evaluated. Results The combination of vancomycin and SBRT was well tolerated, with no grade 3 or 4 adverse events reported. Vancomycin treatment selectively depleted certain bacterial strains while enriching others, leading to significant restructuring of the gut microbiota and alterations in the gut metabolome, including reductions in short-chain fatty acids and shifts in other important immunomodulatory metabolites. These changes were associated with dendritic cell and T cell activation, suggesting enhanced systemic immune engagement. Patients receiving vancomycin showed improved outcomes, with a PFS HR of 0.42 (95% CI 0.18 to 0.96; p=0.049) and OS HR of 0.38 (95% CI 0.14 to 0.99; p=0.033), compared with controls. Conclusions This pilot study demonstrates that gut microbiome modulation using a gram-positive-targeting, gut-restricted antibiotic in combination with SBRT is safe and may improve clinical outcomes in early-stage NSCLC. These findings support further investigation of targeted microbiome modulation strategies as adjuvants to immunogenic therapies like radiation. Trial registration number NCT03546829.

Ovarian granulosa cell tumor characterization identifies FOXL2 as an immunotherapeutic target

Granulosa cell tumors (GCT) are rare ovarian malignancies. Due to the lack of effective treatment in late relapse, there is a clear unmet need for novel therapies. Forkhead Box L2 (FOXL2) is a protein mainly expressed in granulosa cells (GC) and therefore is a rational therapeutic target. Since we identified tumor infiltrating lymphocytes (TILs) as the main immune population within GCT, TILs from 11 GCT patients were expanded, and their phenotypes were interrogated to determine that T cells acquired late antigen-experienced phenotypes and lower levels of PD1 expression. Importantly, TILs maintained their functionality after ex vivo expansion as they vigorously reacted against autologous tumors (100% of patients) and against FOXL2 peptides (57.1% of patients). To validate the relevance of FOXL2 as a target for immune therapy, we developed a plasmid DNA vaccine (FoxL2-tetanus toxin; FoxL2-TT) by fusing Foxl2 cDNA with the immune-enhancing domain of TT. Mice immunization with FoxL2-TT controlled growth of FOXL2-expressing ovarian (BR5) and breast (4T1) cancers in a T cell-mediated manner. Combination of anti-PD-L1 with FoxL2-TT vaccination further reduced tumor progression and improved mouse survival without affecting the female reproductive system and pregnancy. Together, our results suggest that FOXL2 immune targeting can produce substantial long-term clinical benefits. Our study can serve as a foundation for trials testing immunotherapeutic approaches in patients with ovarian GCT.