2190P - First-line atezolizumab in combination with platinum etoposide in patients with metastatic lung large cell neuroendocrine carcinoma (LCNEC)

Background

Large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive cancer that has a poor prognosis. Most patients are diagnosed in the advanced or metastatic stage and there are no standard therapies for this disease. Although immunotherapy has become an increasingly important component of treatment for many types of cancer, there is limited evidence that immunotherapy is effective in treating LCNEC as well.

Methods

This is a prospective non-randomised study evaluating the effectiveness of first-line atezolizumab in combination with platinum etoposide (APE) versus platinum etoposide alone (PE) in patients with metastatic LCNEC. 22 patients were enrolled between September 2018 and May 2022 and were treated at the 3rd Department of Medicine, Sotiria Chest Disease Hospital in Athens Greece. All patients had histological confirmation of lung LCNEC. 5/22 patients were excluded due to previous systemic treatment (limited stage at initial diagnosis). Because of the small sample size and the lack of randomization, cox regression analysis was used to compare clinical outcomes.

Results

10/17 (58.8%) patients received a combination of APE and 7/17 (41.2%) patients received PE alone. Multivariate Cox regression analysis for PFS and OS showed that the median PFS in the combination arm was 6.6 versus 6.3 months in the PE arm (p=0.83, 95% CI 0.97 - 1.15) and the median OS was 11.8 in the APE arm versus 7.9 months in the PE arm (p = 0.20, 95% CI 0.06 - 0.79). At the time of the follow-up cut-off point, five patients in the APE arm had an ongoing response to Atezolizumab treatment with a median duration of response of 15.8 months (defined as the time from response to progression/death or follow up cut-off). There was no correlation between TP53, RB1 IHC expression and OS or PFS in either group.

Conclusions

A combination of atezolizumab and platinum etoposide (APE) showed improved OS and a non-significantly better PFS compared to PE alone in patients with metastatic lung LCNEC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.