ARTICLE ABSTRACT
Purpose: Neoadjuvant combination immune checkpoint blockade and intralesional oncolytic virotherapy have the potential to activate antitumor responses in patients with breast cancer.
Patients and Methods: Eligibility for this pilot phase 1 trial included patients with localized HER2-negative breast cancer who received systemic nivolumab and ipilimumab and intratumor talimogene laherparepvec (T-VEC) (NCT04185311). The primary objective was to evaluate the safety and adverse event profile of immunotherapy combined with T-VEC in patients with localized, HER2-negative breast cancer.
Results: Six patients were enrolled, four having relapses after prior neoadjuvant chemotherapy and two who were previously untreated. Toxicities included one patient having grade 3 hypotension and type 1 diabetes mellitus, three patients with hypothyroidism, and all patients having constitutional symptoms known to be associated with the administration of T-VEC. One patient had a pathological complete response, three patients had pathological partial responses, one showed no significant response, and one had disease progression. Biopsies demonstrated increased immune cell infiltration in samples from patients who responded to therapy.
Conclusions: This triple immunotherapy regimen provided responses in patients with advanced or relapsed HER2-negative breast cancer, at the expense of long-term toxicities.
