Intralesional administration of L19IL2/L19TNF in high-risk locally advanced basal cell carcinoma or cutaneous squamous cell carcinoma.

Abstract

TPS9617 Background: Basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) account for 99% of skin neoplasms, with a rising incidence due to increased sun exposure and growing life expectancy. Approximately 0.8-5% of patients (pts) develop high-risk locally advanced (LA) disease, which is treated with surgery, radiotherapy, sonic hedgehog inhibitors, PD1-based immune checkpoint blockade, or chemotherapy. While surgery offers high cure rates, factors such as location, functional and cosmetic impairment, or patient factors including age, comorbidities, and personal preferences may preclude surgery. Intralesional treatment with immunostimulatory drugs represents an attractive therapeutic approach to treat LA BCC and LA cSCC. Here, we investigate a combination of two immunocytokines (Bifikafusp alfa (L19IL2) and Onfekafusp alfa (L19TNF)) targeting the extradomain B of fibronectin (EDB) for the treatment of high-risk locally advanced BCC and cSCC. EDB is an oncofetal antigen that is undetectable in virtually all healthy adult tissues but becomes highly expressed in tumors, including BCC and cSCC. Methods: In a single-arm phase II study (NCT04362722), pts with locally advanced, non-metastatic, node-negative, single, or multifocal BCC or cSCC not eligible for surgery or radiotherapy are treated with four weekly intratumoral administrations of L19IL2/L19TNF. The study is divided into two parts: a first exploratory part with a total of 40 pts with laBCC or lacSCC, and a second part where the laBCC cohort has been expanded to up to 72 pts not eligible for surgery or radiotherapy. The first part of the trial has been completed with 28 laBCC pts and 12 lacSCC pts evaluable for safety and efficacy. The pre-specified activity goal for the first stage of accrual was met, and the second stage of accrual began in September 2023, with a total of 39 BCC and 18 cSCC pts enrolled so far. Clinical trial information: NCT04362722 .