Exceptional response to trastuzumab deruxtecan in recurrent neuroendocrine cervical cancer: A case report.

Objective: Neuroendocrine cervical carcinomas (NECC) are a rare and aggressive cervical cancer subtype that account for 1-1.5 % of all cervical cancers. Treatment options for recurrent NECC are limited and anticipated response rates are low. Trastuzumab deruxtecan (T-DXd), an antibody drug conjugate with a topoisomerase I inhibitor payload, recently received FDA approval for previously treated patients with HER2+ (IHC3 + ) metastatic solid tumors. Data regarding use of T-DXd in NECC is very limited and it is unclear whether this histology was represented in the trial leading to approval. We sought to describe this unique case of a patient with recurrent NECC who experienced a complete and durable response to T-DXd. Methods: This is a case report and review of the literature. Written informed consent was obtained by the patient prior to submission. Results: We describe a 44-year-old patient with recurrent, metastatic NECC who progressed following two prior lines of therapy, the most recent of which included a multi-drug regimen with topotecan (a topoisomerase I inhibitor). IHC of her tumor tissue demonstrated 3 + HER 2 expression leading to the decision to proceed with treatment with T-DXd. She experienced a partial response (64 % decrease by RECIST) at C6 and subsequent complete response which has now been maintained for > 1 year. She has tolerated therapy well with manageable toxicities and has not required treatment interruption to date. Conclusions: This report demonstrates the role of biomarker driven therapy for rare and aggressive cancer subtypes such as NECC and demonstrates efficacy of T-DXd after previous exposure to topoisomerase I inhibitors.