Among patients with advanced cutaneous squamous-cell carcinoma, cemiplimab induced a response in approximately half the patients and was associated with adverse events that usually occur with immune checkpoint inhibitors. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT02383212 and NCT02760498 .).

BackgroundCemiplimab, a high-affinity, potent human immunoglobulin G4 monoclonal antibody to programmed cell death-1 demonstrated antitumor activity in a Phase 1 advanced cutaneous squamous cell carcinoma (CSCC) expansion cohort (NCT02383212) and the pivotal Phase 2 study (NCT02760498). Here we report the primary analysis of fixed dose cemiplimab 350 mg intravenously every 3 weeks (Q3W) (Group 3) and provide a longer-term update after the primary analysis of weight-based cemiplimab 3 mg/kg intravenously every 2 weeks (Q2W) (Group 1) among metastatic CSCC (mCSCC) patients in the pivotal study (NCT02760498).MethodsThe primary objective for each group was objective response rate (ORR) per independent central review (ICR). Secondary endpoints included ORR by investigator review (INV), duration of response (DOR) per ICR and INV, and safety and tolerability.ResultsFor Group 3 (n=56) and Group 1 (n=59), median follow-up was 8.1 (range, 0.6 to 14.1) and 16.5 (range, 1.1 to 26.6) months, respectively. ORR per ICR was 41.1% (95% CI, 28.1% to 55.0%) in Group 3, 49.2% (95% CI, 35.9% to 62.5%) in Group 1, and 45.2% (95% CI, 35.9% to 54.8%) in both groups combined. Per ICR, Kaplan–Meier estimate for DOR at 8 months was 95.0% (95% CI, 69.5% to 99. 3%) in responding patients in Group 3, and at 12 months was 88.9% (95% CI, 69.3% to 96.3%) in responding patients in Group 1. Per INV, ORR was 51.8% (95% CI, 38.0% to 65.3%) in Group 3, 49.2% (95% CI, 35.9% to 62.5%) in Group 1, and 50.4% (95% CI, 41.0% to 59.9%) in both groups combined. Overall, the most common adverse events regardless of attribution were fatigue (27.0%) and diarrhea (23.5%).ConclusionIn patients with mCSCC, cemiplimab 350 mg intravenously Q3W produced substantial antitumor activity with durable response and an acceptable safety profile. Follow-up data of cemiplimab 3 mg/kg intravenously Q2W demonstrate ongoing durability of responses.Trial registration numberClinicaltrials.gov, NCT02760498. Registered May 3, 2016, https://clinicaltrials.gov/ct2/show/NCT02760498

Normal human consciousness may be impaired by two possible routes: direct reduced function in widespread cortical regions or indirect disruption of subcortical activating systems. The route through which temporal lobe limbic seizures impair consciousness is not known. We recently developed an animal model that, like human limbic seizures, exhibits neocortical deactivation including cortical slow waves and reduced cortical cerebral blood flow (CBF). We now find through functional magnetic resonance imaging (fMRI) that electrically stimulated hippocampal seizures in rats cause increased activity in subcortical structures including the septal area and mediodorsal thalamus, along with reduced activity in frontal, cingulate, and retrosplenial cortex. Direct recordings from the hippocampus, septum, and medial thalamus demonstrated fast poly-spike activity associated with increased neuronal firing and CBF, whereas frontal cortex showed slow oscillations with decreased neuronal firing and CBF. Stimulation of septal area, but not hippocampus or medial thalamus, in the absence of a seizure resulted in cortical deactivation with slow oscillations and behavioral arrest, resembling changes seen during limbic seizures. Transecting the fornix, the major route from hippocampus to subcortical structures, abolished the negative cortical and behavioral effects of seizures. Cortical slow oscillations and behavioral arrest could be reconstituted in fornix-lesioned animals by inducing synchronous activity in the hippocampus and septal area, implying involvement of a downstream region converged on by both structures. These findings suggest that limbic seizures may cause neocortical deactivation indirectly, through impaired subcortical function. If confirmed, subcortical networks may represent a target for therapies aimed at preserving consciousness in human temporal lobe seizures.

Polyaromatic hydrocarbons (PAHs) are prevalent, potent carcinogens, and 7,12-dimethylbenz[a]anthracene (DMBA) is a model PAH widely used to study tumorigenesis. Mice lacking Langerhans cells (LCs), a signatory epidermal dendritic cell (DC), are protected from cutaneous chemical carcinogenesis, independent of T cell immunity. Investigation of the underlying mechanism revealed that LC-deficient skin was relatively resistant to DMBA-induced DNA damage. LCs efficiently metabolized DMBA to DMBA-trans-3,4-diol, an intermediate proximal to oncogenic Hras mutation, and DMBA-treated LC-deficient skin contained significantly fewer Hras mutations. Moreover, DMBA-trans-3,4-diol application bypassed tumor resistance in LC-deficient mice. Additionally, the genotoxic impact of DMBA on human keratinocytes was significantly increased by prior incubation with human-derived LC. Thus, tissue-associated DC can enhance chemical carcinogenesis via PAH metabolism, highlighting the complex relation between immune cells and carcinogenesis.

Background:Over the last decade, several drugs that inhibit class I and/or class II histone deacetylases (HDACs) have been identified, including trichostatin A, the cyclic depsipeptide FR901228 and the antibiotic apicidin. These compounds have had immediate application in cancer research because of their ability to reactivate aberrantly silenced tumour suppressor genes and/or block tumour cell growth. Although a number of HDAC inhibitors are being evaluated in preclinical cancer models and in clinical trials, little is known about the differences in their specific mechanism of action and about the unique determinants of cancer cell sensitivity to each of these inhibitors.Methods:Using a combination of cell viability assays, HDAC enzyme activity measurements, western blots for histone modifications, microarray gene expression analysis and qRT–PCR, we have characterised differences in trichostatin A vs depsipeptide-induced phenotypes in lung cancer, breast cancer and skin cancer cells and in normal cells and have then expanded these studies to other HDAC inhibitors.Results:Cell viability profiles across panels of lung cancer, breast cancer and melanoma cell lines showed distinct sensitivities to the pan-inhibitor TSA compared with the class 1 selective inhibitor depsipeptide. In several instances, the cell lines most sensitive to one inhibitor were most resistant to the other inhibitor, demonstrating these drugs act on at least some non-overlapping cellular targets. These differences were not explained by the HDAC selectivity of these inhibitors alone since apicidin, which is a class 1 selective compound similar to depsipeptide, also showed a unique drug sensitivity profile of its own. TSA had greater specificity for cancer vs normal cells compared with other HDAC inhibitors. In addition, at concentrations that blocked cancer cell viability, TSA effectively inhibited purified recombinant HDACs 1, 2 and 5 and moderately inhibited HDAC8, while depsipeptide did not inhibit the activity of purified HDACs in vitro but did in cellular extracts, suggesting a potentially indirect action of this drug. Although both depsipeptide and TSA increased levels of histone acetylation in cancer cells, only depsipeptide decreased global levels of transcriptionally repressive histone methylation marks. Analysis of gene expression profiles of an isogenic cell line pair that showed discrepant sensitivity to depsipeptide, suggested that resistance to this inhibitor may be mediated by increased expression of multidrug resistance genes triggered by exposure to chemotherapy as was confirmed by verapamil studies.Conclusion:Although generally thought to have similar activities, the HDAC modulators trichostatin A and depsipeptide demonstrated distinct phenotypes in the inhibition of cancer cell viability and of HDAC activity, in their selectivity for cancer vs normal cells, and in their effects on histone modifications. These differences in mode of action may bear on the future therapeutic and research application of these inhibitors.

Chronic graft-versus-host disease (cGVHD) continues to be a major complication after allogeneic hematopoietic cell transplantation, significantly affecting patients' quality of life. A regimen of systemic corticosteroids is considered first-line therapy but is often associated with inadequate responses and multiple side effects. In patients with refractory disease, an evidenced-based consensus is lacking as to the single best approach to managing symptoms. Ruxolitinib, a selective JAK1/2 inhibitor, has recently gained favor as a second-line approach in patients with steroid-refractory cGVHD. In this retrospective study, we evaluated the outcomes of 46 patients who received ruxolitinib for cGVHD between March 2016 and December 2017 at our institution, and evaluated ruxolitinib's impact at 6 and 12 months, based on the National Institutes of Health Severity Scale, including organ-specific responses, and mean prednisone dose. Furthermore, we present the first reported probability of ruxolitinib's treatment failure-free survival (FFS) in patients with cGVHD. After 12 months of ruxolitinib therapy, complete response, partial response, and stable disease was observed in 13% (n = 6), 30.4% (n = 14), and 10.9% (n = 5) of patients, respectively. The 1-year probability of FFS was 54.2% (95% confidence interval, .388 to .673), and ruxolitinib use was associated with a reduction in prednisone dose. In conclusion, our data, which represent the largest cohort of patients with cGVHD reported to date, support the use of ruxolitinib for cGVHD refractory to steroids and currently available salvage therapies, discontinued due to lack of response and high cost.

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous non-Hodgkin’s lymphoma that may variably involve the skin, lymph nodes, and peripheral blood. Malignant burden ranges from cutaneous patches and plaques with little evidence of blood involvement to erythroderma often in association with frank leukemia, as in Sézary syndrome. Toward a better understanding of the pathogenesis of this CD4+ T-cell malignancy, we conducted a high-resolution genomic analysis combining DNA (23 samples) and mRNA (12 samples) data of peripheral blood isolates from CTCL patients across a spectrum of stages. Strikingly, even patients with limited involvement, e.g., normal CD4 counts, contained significant copy-number alterations. Defining genomic characteristics of CTCL blood involvement included gains on 8q and 17q, and deletions on 17p and chromosome 10. A consensus analysis of 108 leukemic CTCL samples demonstrated global similarities among patients with varied blood involvement, narrowing 38 of 62 loci. Toward an annotated framework for in vitro testing, we also characterized genomic alterations in five CTCL cell lines (HH, HUT78, PNO, SeAx, and Sez4), revealing intact core features of leukemic CTCL. Together, these studies produce the most comprehensive view of the leukemic CTCL genome to date, with implications for pathogenesis, molecular classification, and potential future therapeutic developments.

9526 Background: Primary analysis (Oct 2017) of cemiplimab (REGN2810) in pts with mCSCC in a Phase 2 study demonstrated substantial antitumor activity, durable responses, and acceptable safety profile. We now report 12-month follow-up data from these pts (NCT02760498; data cutoff date: Sep 20, 2018). Methods: Pts with mCSCC received cemiplimab 3 mg/kg IV every 2 weeks (Q2W). Tumor measurements were performed Q8W. The primary objective was to evaluate objective response rate (ORR; complete response [CR] + partial response [PR]) according to independent central review (per RECIST 1.1 for scans; modified WHO criteria for photos). Results: 59 pts (median age: 71 years) were enrolled. Median duration of follow-up was 16.5 months (range: 1.1–26.6). ORR by central review was 49.2% (95% CI: 35.9–62.5; 10 CRs and 19 PRs [4 CRs and 25 PRs by investigator-assessment (INV)]). Median duration of response (DOR) has not been reached. The longest DOR at data cut-off was 21.6 months and was still ongoing. Observed DOR exceeded 12 months in 22/29 pts (75.9%) with response. Durable disease control rate (stable disease or response for ≥16 weeks) was 62.7% (95% CI: 49.1–75.0). Median observed time to response was 1.9 months (range: 1.7–9.1). Median progression-free survival was 18.4 months (95% CI: 7.3–not evaluable); median overall survival has not been reached. The most common treatment-emergent adverse events (all grades, Grade ≥3) were diarrhea (28.8%, 1.7%), fatigue (25.4%, 1.7%), and nausea (23.7%, 0%). By INV, grade ≥3 immune-related adverse events occurred in 13.6% of pts. Conclusions: This analysis demonstrates substantial antitumor activity and increasing DOR with cemiplimab 3 mg/kg Q2W in pts with mCSCC. There were no new safety signals. These data strongly support the recent FDA approval of cemiplimab-rwlc for pts with mCSCC or locally advanced CSCC who are not candidates for curative surgery or curative radiation. Clinical trial information: NCT02760498.