Neoantigen-specific cytotoxic Tr1 CD4 T cells suppress cancer immunotherapy.

CD4+ T cells can either enhance or inhibit tumour immunity. Although regulatory T cells have long been known to impede antitumour responses1-5, other CD4+ T cells have recently been implicated in inhibiting this response6,7. Yet, the nature and function of the latter remain unclear. Here, using vaccines containing MHC class I (MHC-I) neoantigens (neoAgs) and different doses of tumour-derived MHC-II neoAgs, we discovered that whereas the inclusion of vaccines with low doses of MHC-II-restricted peptides (LDVax) promoted tumour rejection, vaccines containing high doses of the same MHC-II neoAgs (HDVax) inhibited rejection. Characterization of the inhibitory cells induced by HDVax identified them as type 1 regulatory T (Tr1) cells expressing IL-10, granzyme B, perforin, CCL5 and LILRB4. Tumour-specific Tr1 cells suppressed tumour rejection induced by anti-PD1, LDVax or adoptively transferred tumour-specific effector T cells. Mechanistically, HDVax-induced Tr1 cells selectively killed MHC-II tumour antigen-presenting type 1 conventional dendritic cells (cDC1s), leading to low numbers of cDC1s in tumours. We then documented modalities to overcome this inhibition, specifically via anti-LILRB4 blockade, using a CD8-directed IL-2 mutein, or targeted loss of cDC2/monocytes. Collectively, these data show that cytotoxic Tr1 cells, which maintain peripheral tolerance, also inhibit antitumour responses and thereby function to impede immune control of cancer.

A pilot study of nintedanib in molecularly selected patients with advanced non-small cell lung cancer.

Background: Nintedanib is a small molecule tyrosine kinase inhibitor (TKI) targeting vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and fibroblast growth factor receptor (FGFR). The purpose of the study was to evaluate the response rate for patients with advanced non-small cell lung cancer (NSCLC) with mutations in TP53, VEGFR1-3, PDGFR-A, PDGFR-B, and FGFR1-3 treated with nintedanib as part of an open-label, single-arm pilot study. Methods: Patients with advanced NSCLC previously treated with platinum-doublet chemotherapy with the above mutations were enrolled. Exclusion criteria included necrotic tumors with invasion of blood vessels, history of recent thromboembolic events, increased risk of bleeding or thrombosis, myocardial infarction, and weight loss >10% within past 6 months. Nintedanib was administered at a dose of 200 mg orally twice daily until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Secondary endpoints included progression-free survival (PFS) and correlating outcomes with specific mutations. This study was registered with ClinicalTrials.gov, number NCT02299141. Results: Between 2015 and 2019, 20 patients were enrolled with a median age was 66 years, 15 (75%) were females, 15 (75%) had adenocarcinoma, and 17 patients had a TP53 mutation (85%). Seventeen (85%) had received prior immunotherapy and 11 (55%) had received at least three prior lines of systemic therapy. The ORR was 15% with three partial responses (PR), while 12 patients had stable disease (SD), with disease control rate (DCR) consisting of a PR and SD greater than or equal to 16 weeks of 65% (n=13). Median PFS was 4.3 months [95% confidence interval (CI): 1.8-7.9] and median overall survival (OS) was 11.3 months (95% CI: 3.5-44.2). Three patients experienced prolonged clinical benefit from nintedanib, remaining on treatment for over 1 year and all three had a TP53 mutation and received prior immunotherapy. The most common adverse events of any grade included nausea (80%), fatigue (70%), diarrhea (60%), and anorexia (60%). Conclusions: In this pilot study in heavily pretreated and molecularly selected patients with metastatic NSCLC, nintedanib showed modest activity.

Improvement of Tumor Neoantigen Detection by High-Field Asymmetric Waveform Ion Mobility Mass Spectrometry.

Cancer neoantigens have been shown to elicit cancer-specific T-cell responses and have garnered much attention for their roles in both spontaneous and therapeutically induced antitumor responses. Mass spectrometry (MS) profiling of tumor immunopeptidomes has been used, in part, to identify MHC-bound mutant neoantigen ligands. However, under standard conditions, MS-based detection of such rare but clinically relevant neoantigens is relatively insensitive, requiring 300 million cells or more. Here, to quantitatively define the minimum detectable amounts of therapeutically relevant MHC-I and MHC-II neoantigen peptides, we analyzed different dilutions of immunopeptidomes isolated from the well-characterized T3 mouse methylcholanthrene (MCA)-induced cell line by MS. Using either data-dependent acquisition or parallel reaction monitoring (PRM), we established the minimum amount of material required to detect the major T3 neoantigens in the presence or absence of high field asymmetric waveform ion mobility spectrometry (FAIMS). This analysis yielded a 14-fold enhancement of sensitivity in detecting the major T3 MHC-I neoantigen (mLama4) with FAIMS-PRM compared with PRM without FAIMS, allowing ex vivo detection of this neoantigen from an individual 100 mg T3 tumor. These findings were then extended to two other independent MCA-sarcoma lines (1956 and F244). This study demonstrates that FAIMS substantially increases the sensitivity of MS-based characterization of validated neoantigens from tumors.