Document Type

Article

Publication Date

2019

Publication Title

Clinical Cancer Research: An Official Journal of the American Association for Cancer Research

Volume

26

Issue

3

Pages

598-607

DOI

10.1158/1078-0432.CCR-19-0972

Abstract

Purpose: Interleukin-12 (IL12) promotes adaptive type I immunity and has demonstrated antitumor efficacy, but systemic administration leads to severe adverse events (AE), including death. This pilot trial investigated safety, efficacy, and immunologic activity of intratumoral delivery of IL12 plasmid DNA (tavo) via in vivo electroporation (i.t.-tavo-EP) in patients with Merkel cell carcinoma (MCC), an aggressive virus-associated skin cancer.

Experimental Design: Fifteen patients with MCC with superficial injectable tumor(s) received i.t.-tavo-EP on days 1, 5, and 8 of each cycle. Patients with locoregional MCC (cohort A, N = 3) received one cycle before definitive surgery in week 4. Patients with metastatic MCC (cohort B, N = 12) received up to four cycles total, administered at least 6 weeks apart. Serial tumor and blood samples were collected.

Results: All patients successfully completed at least one cycle with transient, mild (grades 1 and 2) AEs and without significant systemic toxicity. Sustained (day 22) intratumoral expression of IL12 protein was observed along with local inflammation and increased tumor-specific CD8+ T-cell infiltration, which led to systemic immunologic and clinical responses. The overall response rate was 25% (3/12) in cohort B, with 2 patients experiencing durable clinical benefit (16 and 55+ months, respectively). Two cohort A patients (1 with pathologic complete remission) were recurrence-free at 44+ and 75+ months.

Conclusions: I.t.-tavo-EP was safe and feasible without systemic toxicity. Sustained local expression of IL12 protein and local inflammation led to systemic immune responses and clinically meaningful benefit in some patients. Gene electrotransfer, specifically i.t.-tavo-EP, warrants further investigation for immunotherapy of cancer.

Original Publication Citation

Bhatia, S., Longino, N. V., Miller, N. J., Kulikauskas, R. M., Iyer, J. G., Ibrani, D., Blom, A., Byrd, D. R., Parvathaneni, U., Twitty, C. G., Campbell, J. S., Le, M. H., Gargosky, S., Pierce, R. H., Heller, R., Daud, A. I., & Nghiem, P. (2019). Intratumoral delivery of plasmid IL12 via electroporation leads to regression of injected and non-injected tumors in Merkel cell carcinoma. Clinical Cancer Research, 26(3), 598-607. https://doi.org/10.1158/1078-0432.CCR-19-0972

ORCID

0000-0003-1899-3859 (Heller)

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