Project 3: Phase I Study of Anti-PD-1 Antibody MK-3475 and PEG IFNα-2b for Advanced Melanoma

John M. Kirkwood, MD (Clinical Translational Science)
Hassane Zarour, MD (Basic Science)

The goal of this proposal is to test the hypothesis that the combination of pembrolizumab (anti-PD-1 antibody) and pegylated interferon (PEG IFNα-2b) is safe, therapeutically more effective than treatment with single agent anti-PD-1 antibody alone and immunogenic for patients with advanced melanoma irrespective of BRAF or NRAS mutation status. To this end, we have proposed the dose-seeking and efficacy study of the combination pembrolizumab and PEG IFNα-2b for advanced melanoma. This proposal benefits from our well-established expertise in:

  1. IFN-based therapy of melanoma
  2. Immune monitoring of T cell responses to melanoma both in the peripheral blood and at tumor sites
  3. Preclinical studies of inhibitory pathways that dampen T cell responses to melanoma.

This clinical trial is partially funded by an academic-industrial award (Merck and the Melanoma Research Alliance). This project proposes to perform the immunological and biomarker studies in the context of the first-in-human trial with pembrolizumab and PEG IFNα-2b for patients with recurrent inoperable AJCC stage III and metastatic stage IV melanoma.

Specific Aims

Specific Aim 1. Pembrolizumab and PEG IFNα-2b combination therapy promote CD8+ T cell tumor infiltration and the upregulation of PD-L1 as well as multiple co-inhibitory receptors at tumor sites. Here, we propose to test whether treatment with pembrolizumab and PEG IFNα-2b will induce and/or increase CD8+ T cell infiltrates as compared to pre-treatment biopsy evaluation. We will investigate whether CD8+ T cells upregulate co-inhibitory receptors including Tim-3, BTLA, and TIGIT. We will also investigate whether tumor cells upregulate PD-L1 in tumor biopsies pre- and post-treatment.

Specific Aim 2. Anti-PD-1 antibody and PEG IFNα-2b in combination will promote the Th-1 type gene signature in non-inflamed tumors as well as increased expression of inhibitory ligands. Here, we propose to perform transcriptome studies of tumor samples taken prospectively pre- and post-treatment (12 weeks). We will investigate whether the proposed combinatory approach is successfully able to promote a Th-1 gene signature among non-inflamed tumors. We will also evaluate pre- and post-therapy the presence of gene signatures of T cell exhaustion and T cell anergy to investigate the mechanisms driving T cell dysfunction at tumor sites. Such an approach will permit us to identify biomarkers of positive clinical outcome and will also allow us to determine what inhibitory pathways beyond PD-1 may need to be targeted to enhance further the clinical efficacy of the proposed combinatorial therapy.

Specific Aim 3. Anti-PD-1 antibody and PEG IFNα-2b in combination promote clonal expansion of CD8+ T effector cells at tumor sites. Here, we propose to investigate whether the proposed combinatorial therapy will contribute to the expansion of the repertoire of tumor antigen (TA)-specific T cells in the tumor microenvironment. Such studies are important to determine whether the gain of function within TA-specific CD8 T+ TILs is best attributed to one or the other of two non-exclusive mechanisms: 1) functional improvement of persisting clonotypes; and 2) recruitment of particular clonotypes exhibiting superior functional capabilities.


This SPORE project will determine whether PD-1 blockade and PEG-IFN-α2b can prime T cell responses in non-inflamed tumors, which are less likely to respond to anti-PD-1 therapy alone. It will also determine what other inhibitory pathways may need to be targeted in combination with PD-1 blockade and PEG-IFN-α2b to reverse melanoma-induced T cell dysfunction. Finally, it is also expected that the correlative gene signature studies at tumor sites will allow us to understand better the molecular mechanisms driving tumor-induced T cell dysfunction in the tumor microenvironment.