Phase I Trial of Cemiplimab, Radiotherapy, Cyclophosphamide, and Granulocyte Macrophage Colony-Stimulating Factor in Patients with Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma.

LESSONS LEARNED: Cemiplimab in combination with radiation therapy, cyclophosphamide, and granulocyte macrophage colony-stimulating factor did not demonstrate efficacy above what can be achieved with other PD-1 inhibitor monotherapies in patients with refractory and metastatic head and neck squamous cell carcinoma. The safety profile of cemiplimab combination therapy was consistent with previously reported safety profiles of cemiplimab monotherapy. No new safety signal was observed. BACKGROUND: Refractory and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) generally does not respond to PD-1 inhibitor monotherapy. Cemiplimab is a human anti-PD-1 monoclonal antibody. An expansion cohort enrolled patients with R/M HNSCC in a phase I study combining cemiplimab plus radiation therapy (RT), cyclophosphamide, and granulocyte macrophage colony-stimulating factor (GM-CSF). METHODS: Patients with R/M HNSCC refractory to at least first-line therapy and for whom palliative RT is clinically indicated received cemiplimab plus RT, cyclophosphamide, and GM-CSF. The co-primary objectives were the safety, tolerability, and efficacy of cemiplimab plus RT, cyclophosphamide, and GM-CSF in 15 patients with R/M HNSCC. RESULTS: Fifteen patients were enrolled. Patients discontinued treatment due to progression of disease. The most common treatment-emergent adverse events (TEAEs) of any grade were fatigue (40.0%), constipation (26.7%), and asthenia, dyspnea, maculo-papular rash, and pneumonia (each 20%). The only grade ≥3 TEAE that occurred in two patients was pneumonia (13.3%). By investigator assessment, there was one partial response (6.7%); disease control rate was 40.0% (95% confidence interval [CI], 16.3-67.7; five patients with stable disease); seven patients had progressive disease, and two were not evaluable. Median progression-free survival by investigator assessment was 1.8 months (95% CI, 1.7-4.7). CONCLUSION: The regimen demonstrated tolerability but not efficacy above that which can be achieved with anti-PD-1 inhibitor monotherapy for R/M HNSCC.

PD-1 blockade in recurrent or metastatic cervical cancer: Data from cemiplimab phase I expansion cohorts and characterization of PD-L1 expression in cervical cancer.

OBJECTIVES: To characterize the safety, tolerability, and anti-tumor activity of cemiplimab as monotherapy or in combination with hypofractionated radiation therapy (hfRT) in patients with recurrent or metastatic cervical cancer. To determine the association between histology and programmed death-ligand 1 (PD-L1) expression. METHODS: In non-randomized phase I expansion cohorts, patients (squamous or non-squamous histology) received cemiplimab 3 mg/kg intravenously every 2 weeks for 48 weeks, either alone (monotherapy cohort) or with hfRT during week 2 (combination cohort). Due to insufficient tissue material, PD-L1 protein expression was evaluated in commercially purchased samples and mRNA expression levels were analyzed from The Cancer Genome Atlas (TCGA). RESULTS: Twenty patients enrolled in both cohorts in total; 10 had squamous histology. The most common adverse events of any grade were diarrhea, fatigue, and hypokalemia, occurring in 35%, 25%, and 25%, respectively. Objective response rate was 10% in each cohort; responders had squamous histology. Duration of response was 11.2 months and 6.4 months for the responder in the monotherapy and combination cohort, respectively. Irradiated lesions were not included in the response assessments. In separate archived specimens (N = 155), PD-L1 protein expression in tumor and immune cells was negative (<1%) more commonly in adenocarcinoma than in squamous tumors. PD-L1 mRNA levels were lower in adenocarcinoma than squamous cell tumors (1.2 vs 5.0 mean transcripts per million, respectively) in TCGA. CONCLUSIONS: Cemiplimab has activity in cervical squamous cell carcinoma. The phase I results, combined with results from other anti-PD-1 trials in cervical cancer and our biomarker analyses have informed the design of the ongoing phase III trial, with the primary overall survival hierarchical analyses being done first in patients with squamous histology.

First-In-Human Study of Cemiplimab Alone or In Combination with Radiotherapy and/or Low-dose Cyclophosphamide in Patients with Advanced Malignancies.

PURPOSE: This first-in-human study assessed the safety, tolerability, dose-limiting toxicities (DLT), antitumor activity, and pharmacokinetics of cemiplimab, a monoclonal anti-programmed cell death-1 (PD-1), as monotherapy and in combination with hypofractionated radiotherapy (hfRT) and/or cyclophosphamide (CPA) in patients with advanced solid tumors. PATIENTS AND METHODS: Patients were enrolled in 1 of 10 dose escalation cohorts and received cemiplimab 1, 3, or 10 mg/kg every 2 weeks intravenously for up to 48 weeks. Depending on the cohort, patients received hfRT and/or low-dose (200 mg/m2) CPA. Safety was evaluated. Antitumor activity was assessed by Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: Sixty patients were enrolled. The median duration of follow-up was 19.3 weeks (range, 2.3-84.3). There were no DLTs. The most common treatment-emergent adverse events (TEAEs) of any grade were fatigue (45.0%), nausea (36.7%), and vomiting (25.0%). The most common immune-related adverse events (irAEs) of any grade were arthralgia (10.0%), hypothyroidism (8.3%), and maculopapular rash (8.3%). Cemiplimab pharmacokinetic parameters increased in a close to dose-proportional manner and were similar regardless of combination therapy regimen. Two patients (one with cutaneous squamous cell carcinoma and one with cervical cancer) experienced a complete response; 7 had a partial response. Observed duration of response was ≥12 months in 6 patients. CONCLUSIONS: The safety profile of cemiplimab was comparable with other anti-PD-1 agents. Addition of hfRT and/or CPA did not appear to increase grade ≥3 irAEs, suggesting that cemiplimab can be safely administered with hfRT and/or CPA. Cemiplimab exhibited encouraging antitumor activity with 2 complete responses and 7 partial responses observed; responses were also durable.

Genetic analysis of albuminuria in collaborative cross and multiple mouse intercross populations.

Albuminuria is an important marker of nephropathy that increases the risk of progressive renal and chronic cardiovascular diseases. The genetic basis of kidney disease is well-established in humans and rodent models, but the causal genes remain to be identified. We applied several genetic strategies to map and refine genetic loci affecting albuminuria in mice and translated the findings to human kidney disease. First, we measured albuminuria in mice from 33 inbred strains, used the data for haplotype association mapping (HAM), and detected 10 genomic regions associated with albuminuria. Second, we performed eight F(2) intercrosses between genetically diverse strains to identify six loci underlying albuminuria, each of which was concordant to kidney disease loci in humans. Third, we used the Oak Ridge National Laboratory incipient Collaborative Cross subpopulation to detect an additional novel quantitative trait loci (QTL) underlying albuminuria. We also performed a ninth intercross, between genetically similar strains, that substantially narrowed an albuminuria QTL on Chromosome 17 to a region containing four known genes. Finally, we measured renal gene expression in inbred mice to detect pathways highly correlated with albuminuria. Expression analysis also identified Glcci1, a gene known to affect podocyte structure and function in zebrafish, as a strong candidate gene for the albuminuria QTL on Chromosome 6. Overall, these findings greatly enhance our understanding of the genetic basis of albuminuria in mice and may guide future studies into the genetic basis of kidney disease in humans.

Genome-wide association mapping of quantitative traits in outbred mice.

Recent developments in high-density genotyping and statistical analysis methods that have enabled genome-wide association studies in humans can also be applied to outbred mouse populations. Increased recombination in outbred populations is expected to provide greater mapping resolution than traditional inbred line crosses, improving prospects for identifying the causal genes. We carried out genome-wide association mapping by using 288 mice from a commercially available outbred stock; NMRI mice were genotyped with a high-density single-nucleotide polymorphism array to map loci influencing high-density lipoprotein cholesterol, systolic blood pressure, triglyceride levels, glucose, and urinary albumin-to-creatinine ratios. We found significant associations (P < 10(-5)) with high-density lipoprotein cholesterol and identified Apoa2 and Scarb1, both of which have been previously reported, as candidate genes for these associations. Additional suggestive associations (P < 10(-3)) identified in this study were also concordant with published quantitative trait loci, suggesting that we are sampling from a limited pool of genetic diversity that has already been well characterized. These findings dampen our enthusiasm for currently available commercial outbred stocks as genetic mapping resources and highlight the need for new outbred populations with greater genetic diversity. Despite the lack of novel associations in the NMRI population, our analysis strategy illustrates the utility of methods that could be applied to genome-wide association studies in humans.

Non-invasive blood pressure measurement in mice.

Hypertension is a leading cause of heart attack, stroke, and kidney failure and represents a serious medical issue worldwide. The genetic basis of hypertension is well-established, but few causal genes have been identified thus far. Non-invasive blood pressure measurements are a critical component of high-throughput genetic studies to identify genes controlling blood pressure. Whereas this technique is fairly routine for blood pressure measurements in rats, non-invasive blood pressure measurement in mice has proven to be more challenging. This chapter describes an experimental protocol measuring blood pressure in mice using a CODA non-invasive blood pressure monitoring system. This method enables accurate blood pressure phenotyping in mice for linkage or mutagenesis studies, as well as for other experiments requiring high-throughput blood pressure measurement.

Genetic analysis of blood pressure in 8 mouse intercross populations.

The genetic basis of hypertension is well established, yet very few genes that cause common forms of hypertension are known. Quantitative trait locus (QTL) analyses in rodent models can guide the search for human hypertension genes, but the excellent genetic resources for mice have been underused in this regard. To address this issue, we surveyed blood pressure variation in mice from 37 inbred strains and generated 2577 mice in 8 intercross populations to perform QTL analyses of blood pressure. We identified 14 blood pressure QTL in these populations, including > or =7 regions of the mouse genome not linked previously to blood pressure. Many QTL were detected in multiple crosses, either within our study or in studies published previously, which facilitates the use of bioinformatics methods to narrow the QTL and focus the search for candidate genes. The regions of the human genome that correspond to all but 1 of the 14 blood pressure QTL in mice are linked to blood pressure in humans, suggesting that these regions contain causal genes with a conserved role in blood pressure control. These results greatly expand our knowledge of the genomic regions underlying blood pressure regulation in mice and support future studies to identify the causal genes within these QTL intervals.

Validation of volume-pressure recording tail-cuff blood pressure measurements.

BACKGROUND: The American Heart Association has recommended tail-cuff blood pressure measurement for high-throughput experimental designs, including mutagenesis screens and genetic crosses. However, some tail-cuff methods show good agreement with radiotelemetry and others do not, indicating that each tail-cuff method requires independent validation. METHODS: We validated the volume-pressure recording (VPR) tail-cuff method by comparison to simultaneous radiotelemetry measurements. RESULTS: Bland-Altman analysis of 560 cycles from 26 independent measurement sessions showed good agreement between VPR and radiotelemetry measurements, with tail-cuff measurements being 0.25 mm Hg lower than telemetry measurements on average. However, the VPR method was less accurate, compared to radiotelemetry, at extreme high and low (i.e., <110 or >180 mm Hg) systolic blood pressures (SBPs). CONCLUSIONS: We conclude that the VPR tail-cuff method provides accurate blood pressure measurements over the physiological range of blood pressure in mice.