Abstract CT226: A pilot study of adoptive cell therapy with in vitro educated MART1 T cells in combination with ipilimumab for the treatment of metastatic melanoma
Authors: Khoja leila , Joshua Anthony M. , Wang Lisa , Hogg David , Nguyen Linh , Sotov Valentin , Motta Vinicius , Scheid Liz , Gray Diana , Hirano Nato , Butler Marcus O. 
Published: August 2015

Background: The majority of ACT approaches use pre-conditioning lymphodepletion as a prerequisite for achieving clinical activity. For TIL therapy, high dose IL-2 is also required. As an alternative to the toxicity of this approach our group has developed a method for efficiently generating anti-tumor CD8+ T cells, using a novel clinical grade artificial (HLA-A*0201+, CD80+ and CD83+) antigen presenting cell (aAPC).

A completed phase I clinical study (Butler 2011) demonstrated that this aAPC can in vitro-educate tumor antigen specific T cells enabling them to induce responses and establish anti-tumor memory without the use of lymphodepletion, vaccination, or cytokine injections. Detection of transferred aAPC educated MART1 T cells showed trafficking to tumor and an increased frequency of MART1 T cells with a central or effector memory phenotype. Durable responses were seen particularly in patients subsequently treated with ipilimumab.

Trial design: A phase I trial of ACT with our novel in vitro educated CD8+T cells in combination with ipilimumab was designed to evaluate safety, feasibility and efficacy of this novel combination.

Eligible patients must be HLA-A*0201+, ECOG 0/1, have evaluable disease which is MART1+ by IHC and have adequate organ function. Any number of previous therapies are allowed, including ipilimumab. Patients with stable brain metastases will also be eligible.

Patients will undergo leukapheresis to harvest autologous PBMC and a CliniMACs will be used to isolate CD8 T cells for in vitro expansion and priming with MART1 peptide pulsed and irradiated aAPC. One infusion of CD8+ in vitro educated T cells will be given followed by ipilimumab for 4 cycles. Tumor biopsies will be performed at baseline, after 4 cycles of ipilimumab treatment, and at the time of progression. CT assessment scans will be performed at baseline, upon completion of treatment and every three months thereafter. Responses will be determined according to RECIST v1.1 and irRC. Immune correlates will be assessed by serial peripheral phlebotomy at defined time points during treatment; at baseline, prior to each treatment, at the end of all treatment, 3 monthly thereafter and at the time of progression.

A target of ten patients will be recruited. As the primary aim is to assess feasibility and safety of this treatment no formal statistical power is required. We will however use Welch's t test to assess for statistically significant changes (during treatment and follow up) in MART1 T cell frequency and phenotype in two-sample comparisons and the Wilcoxon signed-rank test for paired comparisons.

Citation Format: leila Khoja, Anthony M. Joshua, Lisa Wang, David Hogg, Linh Nguyen, Valentin Sotov, Vinicius Motta, Liz Scheid, Diana Gray, Nato Hirano, Marcus O. Butler. A pilot study of adoptive cell therapy with in vitro educated MART1 T cells in combination with ipilimumab for the treatment of metastatic melanoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT226. doi:10.1158/1538-7445.AM2015-CT226