Epigenetic therapy inhibits metastases by disrupting premetastatic niches.

Cancer recurrence after surgery remains an unresolved clinical problem1-3. Myeloid cells derived from bone marrow contribute to the formation of the premetastatic microenvironment, which is required for disseminating tumour cells to engraft distant sites4-6. There are currently no effective interventions that prevent the formation of the premetastatic microenvironment6,7. Here we show that, after surgical removal of primary lung, breast and oesophageal cancers, low-dose adjuvant epigenetic therapy disrupts the premetastatic microenvironment and inhibits both the formation and growth of lung metastases through its selective effect on myeloid-derived suppressor cells (MDSCs). In mouse models of pulmonary metastases, MDSCs are key factors in the formation of the premetastatic microenvironment after resection of primary tumours. Adjuvant epigenetic therapy that uses low-dose DNA methyltransferase and histone deacetylase inhibitors, 5-azacytidine and entinostat, disrupts the premetastatic niche by inhibiting the trafficking of MDSCs through the downregulation of CCR2 and CXCR2, and by promoting MDSC differentiation into a more-interstitial macrophage-like phenotype. A decreased accumulation of MDSCs in the premetastatic lung produces longer periods of disease-free survival and increased overall survival, compared with chemotherapy. Our data demonstrate that, even after removal of the primary tumour, MDSCs contribute to the development of premetastatic niches and settlement of residual tumour cells. A combination of low-dose adjuvant epigenetic modifiers that disrupts this premetastatic microenvironment and inhibits metastases may permit an adjuvant approach to cancer therapy.

A Multidisciplinary Toxicity Team for Cancer Immunotherapy-Related Adverse Events.

BACKGROUND: Immune checkpoint inhibitors (ICIs) may cause immune-related adverse events (irAEs). Methods to obtain real-time multidisciplinary input for irAEs that require subspecialist care are unknown. This study aimed to determine whether a virtual multidisciplinary immune-related toxicity (IR-tox) team of oncology and medicine subspecialists would be feasible to implement, be used by oncology providers, and identify patients for whom multidisciplinary input is sought. PATIENTS AND METHODS: Patients treated with ICIs and referred to the IR-tox team in August 2017 through March 2018 were identified. Feasibility was defined as receipt of electronic referrals and provision of recommendations within 24 hours of referral. Use was defined as the proportion of referring providers who used the team's recommendations, which was determined through a postpilot survey. Demographics and tumor, treatment, and referral data were collected. Patient features and irAE associations were analyzed. RESULTS: The IR-tox team was found to be feasible and used: 117 referrals from 102 patients were received in 8 months, all providers received recommendations within 24 hours, 100% of surveyed providers used the recommendations, and 74% changed patient management based on IR-tox team recommendations. Referrals were for suspected irAEs (n=106; 91%) and suitability to treat with ICIs (n=11; 10%). In referred patients, median age was 64 years, 54% were men, 13% had prior autoimmunity, and 46% received ICI combinations versus monotherapy (54%). The most commonly referred toxicities were pneumonitis (23%), arthritis (16%), and dermatitis (15%); 15% of patients had multisystem toxicities. Multiple referrals were more common in those treated with combination ICIs (odds ratio [OR], 6.0; P=.035) or with multisystem toxicities (OR, 8.1; P=.005). The IR-tox team provided a new multidisciplinary forum to assist providers in diagnosing and managing complex irAEs. This model identifies educational and service needs, and patients with irAEs for whom multidisciplinary care is most sought. CONCLUSIONS: A virtual multidisciplinary toxicity team for irAEs was a feasible and used service, and facilitated toxicity identification and management.

Five-Year Clinical Outcomes after Neoadjuvant Nivolumab in Resectable Non-Small Cell Lung Cancer.

PURPOSE: Neoadjuvant anti-PD-1 therapy has shown promise for resectable non-small cell lung cancer (NSCLC). We reported the first phase I/II trial of neoadjuvant nivolumab in resectable NSCLC, finding it to be safe and feasible with encouraging major pathological responses (MPR). We now present 5-year clinical outcomes from this trial, representing to our knowledge, the longest follow-up data for neoadjuvant anti-PD-1 in any cancer type. PATIENTS AND METHODS: Two doses of nivolumab (3 mg/kg) were administered for 4 weeks before surgery to 21 patients with Stage I-IIIA NSCLC. 5-year recurrence-free survival (RFS), overall survival (OS), and associations with MPR and PD-L1, were evaluated. RESULTS: With a median follow-up of 63 months, 5-year RFS and OS rates were 60% and 80%, respectively. The presence of MPR and pre-treatment tumor PD-L1 positivity (TPS ≥1%) each trended toward favorable RFS; HR, 0.61 [95% confidence interval (CI), 0.15-2.44] and HR, 0.36 (95% CI, 0.07-1.85), respectively. At 5-year follow-up, 8 of 9 (89%) patients with MPR were alive and disease-free. There were no cancer-related deaths among patients with MPR. In contrast, 6/11 patients without MPR experienced tumor relapse, and 3 died. CONCLUSIONS: Five-year clinical outcomes for neoadjuvant nivolumab in resectable NSCLC compare favorably with historical outcomes. MPR and PD-L1 positivity trended toward improved RFS, though definitive conclusions are limited by cohort size.

Society for Immunotherapy of Cancer (SITC) consensus definitions for immune checkpoint inhibitor-associated immune-related adverse events (irAEs) terminology.

Immune-related adverse events (irAEs) associated with immune checkpoint inhibitor (ICI) therapy may vary substantially in their clinical presentation, including natural history, outcomes to treatment, and patterns. The application of clinical guidelines for irAE management can be challenging for practitioners due to a lack of common or consistently applied terminology. Furthermore, given the growing body of clinical experience and published data on irAEs, there is a greater appreciation for the heterogeneous natural histories, responses to treatment, and patterns of these toxicities, which is not currently reflected in irAE guidelines. Furthermore, there are no prospective trial data to inform the management of the distinct presentations of irAEs. Recognizing a need for uniform terminology for the natural history, response to treatment, and patterns of irAEs, the Society for Immunotherapy of Cancer (SITC) convened a consensus panel composed of leading international experts from academic medicine, industry, and regulatory agencies. Using a modified Delphi consensus process, the expert panel developed clinical definitions for irAE terminology used in the literature, encompassing terms related to irAE natural history (ie, re-emergent, chronic active, chronic inactive, delayed/late onset), response to treatment (ie, steroid unresponsive, steroid dependent), and patterns (ie, multisystem irAEs). SITC developed these definitions to support the adoption of a standardized vocabulary for irAEs, which will have implications for the uniform application of irAE clinical practice guidelines and to enable future irAE clinical trials.

Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers.

BACKGROUND: The benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown. METHODS: We undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible patients had radiologic/cytologic LMM and Eastern Cooperative Oncology Group performance status 0-1. Pembrolizumab was administered intravenously at 200 mg q3W until disease progression/unacceptable toxicity. The primary endpoint was central nervous system (CNS) response after four cycles, defined radiologically/cytologically/clinically. Serial cerebrospinal fluid (CSF) was assessed for tumor-derived DNA (t-DNA) aneuploidy and cytokines. RESULTS: Thirteen of a planned 16 patients were treated between April 2017 and December 2019. The study closed early for poor accrual. Median age was 57 years (range: 22-79). Sixty-two percent of patients had tumors not traditionally ICI-responsive (hormone-receptor (HR)-positive breast carcinoma=39%; high-grade glioma=23%), while 38% had ICI-responsive tumors (non-small cell lung cancer (NSCLC)=23%, head and neck carcinoma=8%, cutaneous squamous carcinoma (CSC)=8%). CNS response was observed in 38% of patients at 12 weeks (95% CI 13.9% to 68.4%) by pre-defined criteria and LM-RANO, and 2 achieved durable complete responses (CSC=1, overall survival (OS) 3+ years; NSCLC=1, OS 9 months). Median CNS progression-free survival and OS was 2.9 months (95% CI 1.3 to NR) and 4.9 months (95% CI 3.7 to NR), respectively. Grade 3+ treatment-related adverse events occurred in 15% of patients. Sensitivity for LMM detection by t-DNA and cytopathology was 84.6% (95% CI 54.6% to 98.1%) and 53.9% (95% CI 25.1% to 80.8%), respectively. Pre-therapy and on-therapy CSF cytokine analysis demonstrated complete responders clustered together. CONCLUSIONS: Pembrolizumab conferred a 38% CNS response rate in patients with LMM, a tolerable safety profile, and deep responses in selected patients with ICI-responsive tumors. CSF t-DNA may be sensitive for LMM detection, and immunologic subsets of CNS response warrant further study. TRIAL REGISTRATION NUMBER: NCT03091478.

Chronic immune checkpoint inhibitor pneumonitis.

BACKGROUND: Pneumonitis from immune checkpoint inhibitors (ICI) is a potentially fatal immune-related adverse event (irAE) from antiprogrammed death 1/programmed death ligand 1 immunotherapy. Most cases of ICI pneumonitis improve or resolve with 4-6 weeks of corticosteroid therapy. Herein, we report the incidence, clinicopathological features and management of patients with non-small cell lung cancer (NSCLC) and melanoma who developed chronic ICI pneumonitis that warrants ≥12 weeks of immunosuppression. METHODS: Patients with ICI pneumonitis were identified from institutional databases of ICI-treated patients with advanced melanoma and NSCLC between January 2011 and July 2018. ICI pneumonitis was defined as clinical/radiographic evidence of lung inflammation without alternative diagnoses, adjudicated by a multidisciplinary team. Chronic ICI pneumonitis was defined as pneumonitis that persists or worsens with steroid tapering, and necessitates ≥12 weeks of immunosuppression, after ICI discontinuation. Serial chest CT was used to assess radiological features, and tumor response by Response EvaluationCriteria for Solid Tumors V.1.1. Bronchoalveolar lavage fluid (BALF) samples were assessed by cell differential. Lung biopsy samples were evaluated by H&E staining and multiplex immunofluorescence (mIF), where available. RESULTS: Among 299 patients, 44 developed ICI pneumonitis (NSCLC: 5/205; melanoma: 1/94), and of these, 6 experienced chronic ICI pneumonitis. The overall incidence of chronic ICI pneumonitis was thus 2%. Of those who developed chronic ICI pneumonitis: the majority had NSCLC (5/6), all sustained disease control from ICIs, and none had other concurrent irAEs. Timing of chronic ICI pneumonitis development was variable (range: 0-50 months), and occurred at a median of 12 months post ICI start. Recrudescence of ICI pneumonitis occurred at a median of 6 weeks after initial steroid start (range: 3-12 weeks), with all patients requiring steroid reintroduction when tapered to ≤10 mg prednisone/equivalent. The median total duration of steroids was 37 weeks (range: 16-43+weeks). Re-emergence of radiographic ICI pneumonitis occurred in the same locations on chest CT, in most cases (5/6). All patients who developed chronic ICI pneumonitis had BALF lymphocytosis on cell differential and organising pneumonia on lung biopsy at initial ICI pneumonitis presentation, with persistent BALF lymphocytosis and brisk CD8+ infiltration on mIF at pneumonitis re-emergence during steroid taper. CONCLUSIONS: A subset of patients who develop pneumonitis from ICIs will develop chronic ICI pneumonitis, that warrants long-term immunosuppression of ≥12 weeks, and has distinct clinicopathological features.

Correction to: persistent mutant oncogene specific T cells in two patients benefitting from anti-PD-1.

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Persistent mutant oncogene specific T cells in two patients benefitting from anti-PD-1.

BACKGROUND: Several predictive biomarkers are currently approved or are under investigation for the selection of patients for checkpoint blockade. Tumor PD-L1 expression is used for stratification of non-small cell lung (NSCLC) patients, with tumor mutational burden (TMB) also being explored with promising results, and mismatch-repair deficiency is approved for tumor site-agnostic disease. While tumors with high PD-L1 expression, high TMB, or mismatch repair deficiency respond well to checkpoint blockade, tumors with lower PD-L1 expression, lower mutational burdens, or mismatch repair proficiency respond much less frequently. CASE PRESENTATION: We studied two patients with unexpected responses to checkpoint blockade monotherapy: a patient with PD-L1-negative and low mutational burden NSCLC and one with mismatch repair proficient colorectal cancer (CRC), both of whom lack the biomarkers associated with response to checkpoint blockade, yet achieved durable clinical benefit. Both maintained T-cell responses in peripheral blood to oncogenic driver mutations - BRAF-N581I in the NSCLC and AKT1-E17K in the CRC - years after treatment initiation. Mutation-specific T cells were also found in the primary tumor and underwent dynamic perturbations in the periphery upon treatment. CONCLUSIONS: These findings suggest that T cell responses to oncogenic driver mutations may be more prevalent than previously appreciated and could be harnessed in immunotherapeutic treatment, particularly for patients who lack the traditional biomarkers associated with response. Comprehensive studies are warranted to further delineate additional predictive biomarkers and populations of patients who may benefit from checkpoint blockade.