Neoadjuvant nivolumab + T-VEC combination therapy for resectable early stage or metastatic (IIIB-IVM1a) melanoma with injectable disease: study protocol of the NIVEC trial.

This single center, single arm, phase II study aims to show an improved major pathologic complete response (pCR) rate, either pCR or near-pCR, up to 45% in 24 patients with resectable stage IIIB-IVM1a melanoma upon neoadjuvant combination treatment with intralesional T-VEC and systemic nivolumab (anti-PD-1 antibody). Patients will receive four courses of T-VEC up to 4 mL (first dose as seroconversion dose) and three doses of nivolumab (240 mg flatdose) every 2 weeks, followed by surgical resection in week nine. The primary endpoint of this trial is pathologic response rate. Secondary endpoints are safety, the rate of delay of surgery and event-free survival. Additionally, prognostic and predictive biomarker research and health-related quality of life evaluation will be performed.

Trials investigating neoadjuvant treatment with immune checkpoint inhibitors (ICI) in patients with melanoma have shown high clinical and pathologic response rates. Treatment with talimogene laherparepvec (T-VEC), a modified herpes simplex virus type-1 (HSV-1), is approved for patients with unresectable stage IIIB-IVM1a melanoma and has the potential to make tumors more susceptible for ICI. Combination ICI and intralesional T-VEC has already been investigated in patients with unresectable stage IIIB-IV disease, however, no data is available yet on the potential benefit of this combination therapy in neoadjuvant setting.

Intralesional T-VEC has the capacity to heighten the immune response and to elicit an abscopal effect in melanoma in combination with ICI. However, the potential clinical benefit of T-VEC plus ICI in the neoadjuvant setting remains unknown. This is the first trial investigating the efficacy and safety of neoadjuvant treatment of T-VEC and nivolumab followed by surgical resection in patients with stage IIIB-IVM1a melanoma, with the potential of high pathologic response rates and acceptable toxicity.

This trial was registered in the European Union Drug Regulating Authorities Clinical Trials Database (EudraCT- number: 2019-001911-22 ) and the Central Committee on Research Involving Human Subjects (NL71866.000.19) on 4th June 2020. Secondary identifying number: NCT04330430 .