Administering Antimicrobial Therapy Before CIT May Be Safer Option in NSCLC

Antimicrobial therapy (AMT) was shown to decrease progression-free survival (PFS) when taken before immunotherapy with a checkpoint inhibitor (CPI) for lung cancer. However, AMT had no significant effect on PFS when administered before chemotherapy/immunotherapy (CIT), which could make CIT a preferable treatment for non–small cell lung cancer (NSCLC).

Study findings were published in Journal of Cancer Research and Clinical Oncology.

This study included patients with NSCLC stage IV (N = 114; mean [SD] age, 65 [8.5] years) who were treated in Germany. All patients were treated with a CPI alone or CIT. The timing and presence of AMT were recorded and prior therapy lines for NSCLC were accepted, "according to guidelines," the study authors noted. Patients with data on AMT and PFS were included in this study, with AMT defined as at least a 5-day treatment period.

Participants were split into 3 groups: patients with AMT in the month before CPI or CIT treatment (n = 42), patients with AMT during CPI or CIT treatment(n = 49), and patients without AMT and CPI or CIT therapy(n = 64). Sixty-one patients received a CPI and 53 patients received CIT.

Twenty-five patients receiving CIT had AMT in the month before the start of CIT, 16 patients had AMT during CIT, 17 patients receiving a CPI had AMT 1 month before the start of CPI treatment, and 23 patients had AMT during CPI treatment. Eighty patients had died by the final analysis, with the remaining 34 patients treated with a CPI.

The median PFS with CIT was 6 (3.2) months compared with 8 (2.7) months with CPI therapy, and this measure was comparable in patients in group 1 who received CPI and CIT treatment (4 [1.02] vs 6 [1.2] months, respectively). Those who received a CPI in group 2 had a slightly higher median PFS that those with CIT in group 2 (8 [2.1] vs 3 [2.4] months), as did patients in group 4 who received a CPI vs CIT (14 [1.02] vs 10 [2.5] months).

Significantly longer PFS was seen in patients who took a CPI without AMT compared with patients receiving a CPI and AMT in the month before therapy started (14 [1.02] vs 4 [1.02] months), and patients receiving CIT without AMT had a slightly longeer PFS compared with patients receiving CIT with AMT (10 [2.5] vs 6 [1.2] months). Adjusting for the number of comorbidities produced no significant difference.

There were limitations to this study. Thepatient population was small and changes in the microbiome under AMT were not observed. Patients with an infection often have reduced clinical status and may have affected the results of the study as well.

The researchers concluded that their data were hypothesis generating, with a proposed hypothesis of CIT being more resistant to dysbiosis, which could lead to a preference for CIT if AMT is started before therapy in patients with NSCLC stage IV. They recommend a larger study to validate their findings.

Reference

Uhlenbruch M, Kruger S. Effect of antimicrobial therapy on progression-free survival of immunotherapy and chemo-/immunotherapy in patients with non-small cell lung cancer. J Cancer Res Clin Oncol. Published online January 3, 2023. doi:10.1007/s00432-022-04567-0