No abstract

Immune checkpoint blockade represents a major breakthrough in cancer therapy, however responses are not universal. Genomic and immune features in pre-treatment tumor biopsies have been reported to correlate with response in patients with melanoma and other cancers, but robust biomarkers have not been identified. We studied a cohort of metastatic melanoma patients initially treated with cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) blockade (n=53) followed by programmed death-1 (PD-1) blockade at progression (n=46), and analyzed immune signatures in longitudinal tissue samples collected at multiple time points during therapy. In these studies, we demonstrate that adaptive immune signatures in tumor biopsy samples obtained early during the course of treatment are highly predictive of response to immune checkpoint blockade, and also demonstrate differential effects on the tumor microenvironment induced by CTLA-4 and PD-1 blockade. Importantly, potential mechanisms of therapeutic resistance to immune checkpoint blockade were also identified. Significance These studies demonstrate that adaptive immune signatures in early on-treatment tumor biopsies are predictive of response to checkpoint blockade, and yield insight into mechanisms of therapeutic resistance. These concepts have far-reaching implications in this age of precision medicine, and should be explored in immune checkpoint blockade treatment across cancer types.

Preclinical studies suggest that treatment with neoadjuvant immune checkpoint blockade is associated with enhanced survival and antigen-specific T cell responses over adjuvant treatment 1 ; however, optimal regimens have not been defined. Herein, we report results from a randomized phase II study of neoadjuvant nivolumab versus combined ipilimumab with nivolumab in 23 patients with high-risk resectable melanoma (NCT02519322). RECIST overall response rates (ORR), pathologic complete response rates (pCR), treatment-related adverse events (trAEs), and immune correlates of response were assessed. Treatment with combined ipilimumab and nivolumab yielded high response rates (RECIST ORR 73%, pCR 45%) but substantial toxicity (73% grade 3 trAEs), whereas treatment with nivolumab monotherapy yielded modest responses (ORR 25%, pCR 25%) and low toxicity (8% grade 3 trAEs). Immune correlates of response were identified, demonstrating higher lymphoid infiltrates in responders to both therapies and a more clonal and diverse T cell infiltrate in responders to nivolumab monotherapy. These results are the first to describe the feasibility of neoadjuvant immune checkpoint blockade in melanoma and emphasize the need for additional studies to optimize treatment regimens and to validate putative biomarkers.

Background: Preclinical models showed that blocking PD-1/PD-L1 pathways enhanced anti-leukemic responses. Azacitidine up-regulates PD-1 and interferon-gamma signaling. Methods: In this single arm trial, patients with relapsed/refractory (R/R) AML were treated with azacitidine 75mg/m2 Days 1–7 intravenously or subcutaneously with nivolumab 3mg/kg intravenously on Day 1 and 14, every 4–6 weeks. Findings: Seventy patients were treated. The median age was 70 years (range, 22–90). The median number of prior therapies received was 2 (range, 1–7). The overall response rate (ORR) was 33% including 15 (22%) complete remission (CR)/complete remission with insufficient recovery of counts (CRi), 1 partial response, and 7 patients with hematologic improvement (HI) maintained >6 months. Six patients (9%) had stable disease >6 months. The ORR was 58% and 22%, in HMA-naïve (n=25) and HMA pre-treated (n=45) patients, respectively. Grade 3–4 immune related adverse events occurred in 8 (11%) patients. Pretherapy bone marrow and peripheral blood CD3 and CD8 were significantly predictive for response on flow-cytometry. CTLA-4 was significantly up-regulated on CD4+Teff in non-responders after 2 and 4 doses of nivolumab. Interpretation: Azacitidine and nivolumab therapy produced an encouraging response rate and overall survival in patients with R/R AML, particularly in HMA-naïve and Salvage 1 patients. Pretherapy bone marrow aspirate and peripheral blood CD3 percentage may be biomarkers for patient selection. Trial Registration ID: Clinicaltrials.gov identifier: NCT02397720

To date, anti-CTLA-4 (ipilimumab) or anti-PD-1 (nivolumab) monotherapy has not demonstrated significant clinical benefit in patients with prostate cancer. To identify additional immune inhibitory pathways in the prostate tumor microenvironment, we evaluated untreated and ipilimumab-treated tumors from patients on a pre-surgical clinical trial. PD-L1 and VISTA inhibitory molecules increased on independent subsets of macrophages. Our data suggest that VISTA is another compensatory inhibitory pathway in prostate tumors after ipilimumab therapy.

We report the first case series of ICI-associated colitis successfully treated with fecal microbiota transplantation (FMT), with reconstitution of the gut microbiome and a relative increase in the proportion of regulatory T cells (Tregs) within the colonic mucosa. These preliminary data provide evidence that modulation of the gut microbiome may abrogate ICI-associated colitis.

Immune checkpoint therapy (ICT) with anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of ICT is limited to a subset of patients with specific tumor types 1,2. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing, however, the mechanistic rationale for tumor specific targeting of immune checkpoints remains elusive. To garner insight into tumor specific immunomodulatory targets, we analyzed tumors (N=94) representing 5 different cancer types, including those that respond relatively well to ICT and those that do not, such as glioblastoma (GBM), prostate cancer (PCa) and colorectal cancer (CRC). Through mass cytometry and single cell RNA-sequencing, we identified a unique population of CD73 hi macrophages in GBM that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in GBM, we performed reverse translational studies using CD73 −/− mice. We found that the absence of CD73 improved survival in a murine model of GBM treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve anti-tumor immune responses to ICT in GBM, and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.

Summary Background Squamous cell carcinoma of the anal canal (SCCA) is a rare malignancy associated with infection by human papillomavirus (HPV). No consensus treatment approach exists for the treatment of metastatic disease. Because intratumoral HPV oncoproteins upregulate immune checkpoint proteins such as PD-1 to evade immune-mediated cytotoxicity, we did a trial of the anti-PD-1 antibody nivolumab for patients with metastatic SCCA. Methods We did this single-arm, multicentre, phase 2 trial at ten academic centres in the USA. We enrolled patients with treatment-refractory metastatic SCCA, who were given nivolumab every 2 weeks (3 mg/kg). The primary endpoint was response according to Response Evaluation Criteria in Solid Tumors, version 1.1, in the intention-to-treat population. At the time of data cutoff, the study was ongoing, with patients continuing to receive treatment. The study is registered with ClinicalTrials.gov, number NCT02314169. Findings We screened 39 patients, of whom 37 were enrolled and received at least one dose of nivolumab. Among the 37 patients, nine (24% [95% CI 15–33]) had responses. There were two complete responses and seven partial responses. Grade 3 adverse events were anaemia (n=2), fatigue (n=1), rash (n=1), and hypothyroidism (n=1). No serious adverse events were reported. Interpretation To our knowledge, this is the first completed phase 2 trial of immunotherapy for SCCA. Nivolumab is well tolerated and effective as a monotherapy for patients with metastatic SCCA. Immune checkpoint blockade appears to be a promising approach for patients with this orphan disease. Funding National Cancer Institute/Cancer Therapy Evaluation Program, the HPV and Anal Cancer Foundation, the E B Anal Cancer Fund, The University of Texas MD Anderson Moon Shots Program, and an anonymous philanthropic donor.