Avelumab for the treatment of locally advanced or metastatic Merkel cell carcinoma-A multicenter real-world experience in Israel

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and aggressive malignancy of the skin, affecting predominantly the fair-skinned older population exposed to high levels of ultraviolet light. Immune suppression is considered a significant risk factor. With the recent advances in the field of immunotherapy, the treatment paradigm for advanced MCC, traditionally based on chemotherapy, has largely shifted to anti-PD-L1 and PD-1 agents such as avelumab and pembrolizumab, respectively. However, real-world data remain sparse. The aim of this study was to assess real-world evidence of the effectiveness of avelumab in a diverse group of patients with MCC in Israel.

METHODS

The electronic databases of five university hospitals in Israel were searched for all consecutive patients with MCC treated with at least one dose of avelumab in 2018-2022. Data on baseline, disease-related, treatment-related, and outcome parameters were collected and analyzed.

RESULTS

The cohort included 62 patients of whom 22% were immune-suppressed. The overall response rate to avelumab was 59%. The median progression-free survival was 8.1 months, and the median overall survival, 23.5 months, with no differences between immune-competent and immune-suppressed patients. Treatment was well tolerated; any-grade toxicity developed in 34% of patients, and grade 3-4 toxicity, in 14%.

CONCLUSIONS

Avelumab was found to be effective and safe for the treatment of advanced MCC in a diverse group of patients, including some with immune suppression. Further studies are warranted to evaluate the optimal sequence and duration of treatment and to assess the potential role of avelumab for earlier stages of MCC.

JS1.3 Autoimmune encephalitis as immune related adverse event (irAE) of check point inhibitors (CPI) not so rare as we thought

INTRODUCTION

CPI has significant efficacy and toxicities. We describe our experience with CPI treated patients diagnosed with irAE encephalitis.

METHODS

Patients treated with CPI during 2017–2018 were identified from institute’s EMR. Patients treated for irAE encephalitis were identified from the database of the Neuro-Oncology Unit of the Institute. Results: Eleven patients were diagnosed with irAE encephalitis out of 1500 treated with CPI at the Institute (0.73%). Four patients had NSCLC, 3 had melanoma, the one patient had each of SCLC, uterine carcinoma, RCC and breast cancer. Median age was 69 years (49–87). Four of 11 were treated with chemo-CPI, 3-with CPI combinations. Median onset of symptoms was at 19 days (5–180) following initial treatment. All events were high grade severity. Eight patients fully recovered after immunotherapy discontinuation and steroid treatment, of these, 2 melanoma patients underwent uncomplicated CPI re-challenge. Three patients, all non-melanoma, had severe neurological sequelae. Two of them were treated with steroids, PLEX and cyclophosphamide: one improved neurologically although died 6 months later from cancer. One patient was oncologically stable but died from neurological deterioration 7 months later. The additional patient was treated with steroids only because his advanced age and decease in hospice 2 months later.

CONCLUSION

Encephalitis, as an irAE of CPI, seems to be more common and severe than previously thought, predominantly in non melanoma patients. Nevertheless, in the majority of cases it is reversible and in some melanoma patients immunotherapy re-challenge is safe. Future studies will have to define risk factors and severity prediction.