CD70-Targeted Allogeneic CAR T-Cell Therapy for Advanced Clear Cell Renal Cell Carcinoma.

Therapeutic approaches for clear cell renal cell carcinoma (ccRCC) remain limited; however, chimeric antigen receptor (CAR) T-cell therapies may offer novel treatment options. CTX130, an allogeneic CD70-targeting CAR T-cell product, was developed for the treatment of advanced or refractory ccRCC. We report that CTX130 showed favorable preclinical proliferation and cytotoxicity profiles and completely regressed RCC xenograft tumors. We also report results from 16 patients with relapsed/refractory ccRCC who received CTX130 in a phase I, multicenter, first-in-human clinical trial. No patients encountered dose-limiting toxicity, and disease control was achieved in 81.3% of patients. One patient remains in a durable complete response at 3 years. Finally, we report on a next-generation CAR T construct, CTX131, in which synergistic potency edits to CTX130 confer improved expansion and efficacy in preclinical studies. These data represent a proof of concept for the treatment of ccRCC and other CD70+ malignancies with CD70- targeted allogeneic CAR T cells. Significance: Although the role of CAR T cells is well established in hematologic malignancies, the clinical experience in solid tumors has been disappointing. This clinical trial demonstrates the first complete response in a patient with RCC, reinforcing the potential benefit of CAR T cells in the treatment of solid tumors.

Real-world assessment of the treatment patterns and outcomes among patients with multiple myeloma across different risk stratification criteria in the United States: a retrospective cohort study.

This study evaluated prognostic performance of International Staging System (ISS), revised ISS, and chromosomal abnormalities (CA) in newly diagnosed multiple myeloma patients to describe treatment patterns (cohort 1; n = 1979) and survival outcomes (cohort 2; n = 1382). In both cohorts, ∼18%, 41%, and 37% of patients were high-risk according to the R-ISS, ISS, and high-risk CA criteria, respectively. Across all risk stratification criteria, 60% of patients received triplets. In cohort 2, the median modified progression-free survival decreased with each increasing risk stage (23.5, 12.1, and 8.8 months in R-ISS I, II, and III, respectively, and 16.0, 12.7, and 10.4 months in ISS I, II, and III). Similar trends were observed in the proportions of two-year overall survival. In conclusion, R-ISS has greater discriminatory power than ISS or high-risk CA alone and can be implemented in a real-world setting. Accordingly, a more risk-adapted approach can be feasible, with a greater population-level impact.

A phase I study of the safety and efficacy of talimogene laherparepvec in Japanese patients with advanced melanoma.

Talimogene laherparepvec (T-VEC) is approved for the treatment of unresectable melanoma in the USA, Europe, and Australia. This phase I, multicenter, open-label, dose de-escalation study evaluated the safety and efficacy of T-VEC in Japanese patients with unresectable stage IIIB-IV melanoma. Eligible adult patients had histologically confirmed stage IIIB-IVM1c cutaneous melanoma, may have received prior systemic anticancer therapy, must have had ≥1 injectable lesion, serum lactate dehydrogenase ≤1.5x upper limit of normal, ECOG performance status of 0 or 1, and adequate hematologic, hepatic, and renal function. T-VEC was injected intralesionally (first dose, ≤4.0 ml of 106  PFU/ml; after 3 weeks and then every 2 weeks thereafter, ≤4.0 ml of 108  PFU/ml). Primary endpoints were dose-limiting toxicities (DLTs) and durable response rate (DRR). Of 18 enrolled patients (72.2% female), 16 had received ≥1 prior line of therapy. Ten patients discontinued T-VEC due to disease progression. Median (range) follow-up was 20.0 (4-37) months. No DLTs were observed; 17 (94.4%) patients had treatment-emergent adverse events (AEs). Fourteen (77.8%) patients had treatment-related AEs; the most frequent were pyrexia (44.4%), malaise (16.7%), chills, decreased appetite, pruritus, and skin ulcer (11.1% each). The primary efficacy endpoint was met: 2 (11.1%) patients had a durable partial response ≥6 months. The DRR was consistent with that observed in a phase III trial of T-VEC in non-Asian patients. The safety profile was consistent with the patients' underlying disease and the known safety profile of T-VEC.

An Overview of Characteristics of Clinical Next-Generation Sequencing-Based Testing for Hematologic Malignancies.

CONTEXT.­: With the increasing integration of molecular alterations into the evaluation of hematologic malignancies (HM), somatic mutation profiling by next-generation sequencing (NGS) has become a common clinical testing strategy. Limited data are available about the characteristics of these assays. OBJECTIVE.­: To describe assay characteristics, specimen requirements, and reporting practices for NGS-based HM testing using College of American Pathologists proficiency testing survey data. DESIGN.­: The College of American Pathologists NGS Hematologic Malignancies Survey (NGSHM) results from 78 laboratories were used to determine laboratory practices in NGS-based HM testing. RESULTS.­: The majority of laboratories performed tumor-only (88.5% [69 of 78]), targeted sequencing of cancer genes or mutation hotspots (98.7% [77 of 78]); greater than 90% performed testing on fresh bone marrow and peripheral blood. The majority of laboratories reported a 5% lower limit of detection for single-nucleotide variants (73.1% [57 of 78]) and small insertions and deletions (50.6% [39 of 77]). A majority of laboratories used benchtop sequencers and custom enrichment approaches. CONCLUSIONS.­: This manuscript summarizes the characteristics of clinical NGS-based testing for the detection of somatic variants in HM. These data may be broadly useful to inform laboratory practice and quality management systems, regulation, and oversight of NGS testing, and precision medicine efforts using a data-driven approach.

Plasma IL-6 changes correlate to PD-1 inhibitor responses in NSCLC.

BACKGROUND: Blood-based biomarkers of anti-solid tumor immune checkpoint blockade (ICB) response are lacking. We hypothesized that changes in systemic cytokine levels with the initial doses of programmed cell death protein 1 (PD-1) pathway inhibitors would correlate with clinical responses. New ultrasensitive ELISA technology enables quantitation of plasma proteins in sub-picogram-per-milliliter concentrations. METHODS: We measured plasma cytokines by ultrasensitive single-molecule array assays in patients with non-small-cell lung carcinoma before and during treatment with anti-PD-1 therapy. Association with best overall response and progression-free survival (PFS) was assessed by Kruskall-Wallis test and Kaplan-Meier plots with log-rank test, respectively. RESULTS: A decrease in interleukin 6 (IL-6) levels was associated with improved PFS (n=47 patients, median PFS: 11 vs 4 months, HR 0.45 (95% CI 0.23 to 0.89), p=0.04). The extent of change in IL-6 differed between best overall response categories (p=0.01) and correlated with changes in C reactive protein levels. We also explored plasma cytokine levels in relation to immune-related adverse effects and observed some correlation. CONCLUSIONS: This study suggests the presence of a systemic, proteomic reflection of successful ICB outside the tumor microenvironment with plasma decreases in IL-6 and CRP.

Proficiency Testing of Standardized Samples Shows High Interlaboratory Agreement for Clinical Next Generation Sequencing-Based Hematologic Malignancy Assays With Survey Material-Specific Differences in Variant Frequencies.

CONTEXT.­: As laboratories increasingly turn from single-analyte testing in hematologic malignancies to next-generation sequencing-based panel testing, there is a corresponding need for proficiency testing to ensure adequate performance of these next-generation sequencing assays for optimal patient care. OBJECTIVE.­: To report the performance of laboratories on proficiency testing from the first 4 College of American Pathologists Next-Generation Sequencing Hematologic Malignancy surveys. DESIGN.­: College of American Pathologists proficiency testing results for 36 different engineered variants and/or allele fractions as well as a sample with no pathogenic variants were analyzed for accuracy and associated assay performance characteristics. RESULTS.­: The overall sensitivity observed for all variants was 93.5% (2190 of 2341) with 99.8% specificity (22 800 of 22 840). The false-negative rate was 6.5% (151 of 2341), and the largest single cause of these errors was difficulty in identifying variants in the sequence of CEBPA that is rich in cytosines and guanines. False-positive results (0.18%; 40 of 22 840) were most likely the result of preanalytic or postanalytic errors. Interestingly, the variant allele fractions were almost uniformly lower than the engineered fraction (as measured by digital polymerase chain reaction). Extensive troubleshooting identified a multifactorial cause for the low variant allele fractions, a result of an interaction between the linearized nature of the plasmid and the Illumina TruSeq chemistry. CONCLUSIONS.­: Laboratories demonstrated an overall accuracy of 99.2% (24 990 of 25 181) with 99.8% specificity and 93.5% sensitivity when examining 36 clinically relevant somatic single-nucleotide variants with a variant allele fraction of 10% or greater. The data also highlight an issue with artificial linearized plasmids as survey material for next-generation sequencing.

Single-Molecule Arrays for Ultrasensitive Detection of Blood-Based Biomarkers for Immunotherapy.

Single-molecule array (Simoa) technology enables ultrasensitive protein detection that is suited to the development of peripheral blood-based assays for assessing immuno-oncology responses. We adapted a panel of Simoa assays to measure systemic cytokine levels from plasma and characterized physiologic variation in healthy individuals and preanalytic variation arising from processing and handling of patient samples. Insights from these preclinical studies led us to a well-defined set of Simoa assay conditions, a specimen processing protocol, and a data processing approach that we describe here. Simoa enables accurate quantitation of soluble immune signaling molecules in an unprecedented femtomolar range, opening up the potential for liquid biopsy-type approaches in immuno-oncology. We are using the method described here to distinguish PD-1 inhibitor nonresponders as early as after one dose after therapy and envision applications in characterizing PD-1 inhibitor resistance and detection of immune-related adverse effects.

Impact of clinical sample handling and processing on ultra-low level measurements of plasma cytokines.

OBJECTIVES: In this study, we evaluated the impact of clinical sample handling and processing on IL-6, IL-10, IFNγ, and IL-2 measurements in plasma. DESIGN AND METHODS: We collected whole blood samples and analyzed various pre-analytical parameters. We assessed the following: 1) cytokine stability in whole blood that was stored over a ten-hour period at room temperature and 4 °C; 2) cytokine stability in plasma over 6 h; 3) vigorous sample handling including repeated dropping and transport through a pneumatic transport system; and 4) freeze-thaw stability of cytokines in plasma. To ensure ability to measure IL-6, IL-10, IFNγ, and IL-2 levels in plasma, we used Simoa, an ultra-sensitive immunoassay platform. RESULTS: We show that whole blood storage at room temperature results in decreased cytokine levels and that whole blood storage at 4 °C results in greater cytokine stability. We also show that cytokines are stable when whole blood samples are subjected to vigorous sample handling. Lastly, we show that cytokines are stable in plasma over three freeze-thaw cycles. CONCLUSIONS: Clinical sample handling and processing can affect measurements of IL-6, IL-10, IFNγ, and IL-2 in plasma. We believe this study will be a useful reference for future studies in which these cytokines are used as potential biomarkers.

Development of a Commercial Reference Laboratory Elective Rotation for Residents in Clinical Pathology.

OBJECTIVES: To develop a curriculum for a commercial reference laboratory clinical pathology training elective. METHODS: A 4-day elective at Quest Diagnostics was developed. The elective included 32 sessions composed of interactive didactic sessions and laboratory tours/demonstrations. Ten residents who attended the elective completed a written evaluation and scored each component of the curriculum. RESULTS: Written comments were very positive and demonstrated the goals of the elective were achieved. Laboratory tours and one-on-one sessions with the medical directors were especially well received. Most of the residents stated that the rotation gave them exposure to an area of laboratory medicine that they were not familiar with. CONCLUSIONS: The elective provided a resident training experience that was highly regarded and exposed residents to an area of laboratory medicine not encountered in most pathology training programs. Our curriculum could serve as a model for establishing a similar elective in other training programs.

High-Throughput Screening of a Luciferase Reporter of Gene Silencing on the Inactive X Chromosome.

Assays of luciferase gene activity are a sensitive and quantitative reporter system suited to high-throughput screening. We adapted a luciferase assay to a screening strategy for identifying factors that reactivate epigenetically silenced genes. This epigenetic luciferase reporter is subject to endogenous gene silencing mechanisms on the inactive X chromosome (Xi) in primary mouse cells and thus captures the multilayered nature of chromatin silencing in development. Here, we describe the optimization of an Xi-linked luciferase reactivation assay in 384-well format and adaptation of the assay for high-throughput siRNA and chemical screening. Xi-luciferase reactivation screening has applications in stem cell biology and cancer therapy. We have used the approach described here to identify chromatin-modifying proteins and to identify drug combinations that enhance the gene reactivation activity of the DNA demethylating drug 5-aza-2'-deoxycytidine.

Flow cytometric minimal residual disease assessment of peripheral blood in acute lymphoblastic leukaemia patients has potential for early detection of relapsed extramedullary disease.

OBJECTIVES: To evaluate peripheral blood (PB) for minimal residual disease (MRD) assessment in adults with acute lymphoblastic leukaemia (ALL). METHODS: We analysed 76 matched bone marrow (BM) aspirate and PB specimens independently for the presence of ALL MRD by six-colour flow cytometry (FC). RESULTS: The overall rate of BM MRD-positivity was 24% (18/76) and PB was also MRD-positive in 22% (4/18) of BM-positive cases. We identified two cases with evidence of leukaemic cells in PB at the time of the extramedullary relapse that were interpreted as MRD-negative in BM. CONCLUSIONS: The use of PB MRD as a non-invasive method for monitoring of systemic relapse may have added clinical and diagnostic value in patients with high risk of extramedullary disease.