Impact of the COVID-19 pandemic on staging at presentation of patients with invasive melanoma

e21579

Background: The COVID-19 pandemic has impacted cancer care beyond the direct implications of viral infection. Delays in presentation and diagnosis may lead to more advanced disease and worse patient outcomes. We evaluated the impact of the pandemic on patients (pts) with melanoma (mel). Methods: A single-institution, retrospective comparison of pts with newly diagnosed invasive mel or metastatic recurrence prior to (pre-cohort, n = 246) and after (post-cohort, n = 246) declaration of the COVID-19 pandemic on March 11, 2020. 492 pts were evaluated between March 1, 2019 and January 12, 2021. Key variables collected included demographics, pathology, stage at diagnosis, surgical management, receipt of adjuvant or systemic therapy, and follow up. Categorical variables were compared using the two-sided Fisher’s exact test, continuous variables were compared using the two-sided Wilcoxon rank sum test, and survival endpoints were evaluated with the Kaplan-Meier method. This study was exempt from review by the IRB. Results: 200 (81.3%) pts presented with early-stage disease and 46 (18.7%) pts presented with metastatic disease in the post-cohort, compared to 209 (85%) and 37 (15%) pts in the pre-cohort, respectively. In the post-cohort there was a significant decrease in stage I pts (28.5% vs 40.7%, p = 0.006), a significant increase in stage III pts (30.5% vs 21.1%, p = 0.023), and a significant increase in pts with metastatic recurrence (7.7% vs 3.3%, p = 0.046) compared to the pre-cohort. There was also a significant increase in pts with brain metastases (BM) in the post-cohort (6.5% vs 1.6%, p = 0.010). For pts with early-stage disease, there was a significant increase in median Breslow depth (2.0 vs 1.4 mm, p = 0.047) and mitotic rate > 1 (78.1% vs 66%, p = 0.008) in the post-cohort. There were trends toward increased ulceration, lymphovascular/perineural invasion, and microsatellite presence. Pts receiving adjuvant therapy in the post-cohort were significantly more likely to receive oral targeted therapy (37.6% vs 27.5%) compared to IV immunotherapy (62.4% vs 72.5%), p = 0.034, perhaps reflecting an attempt to minimize in-person visits. There was not a significant difference between the 2 groups in the type of systemic therapy administered in the metastatic setting. Median progression-free and overall survival were not reached due to a limited number of events in each arm. Conclusions: There was a significant decrease in pts with stage I mel along with a significant increase in pts with stage III mel, metastatic recurrence, and BMs presenting to our institution during the pandemic. Findings are likely related to delays from both the patient (to avoid interaction with the healthcare system - including primary care, dermatology, and oncology) and from the system itself, with some clinics potentially evaluating pts in a limited capacity. These data reaffirm the importance of early detection and evaluation of melanoma.

PSMA targeted armored chimeric antigen receptor (CAR) T-cells in patients with advanced mCRPC: A phase I experience

2534

Background: CART-PSMA-TGFβRDN cells are autologous T cells engineered via lentiviral transduction to express a dominant negative form of TGFβRII (TGFβRDN) and a chimeric antigen receptor (CAR) with specificity to prostate specific membrane antigen (PSMA). The TGFβRDN renders CAR T cells resistant to TGFβ-mediated immunosuppression. CART-PSMA-02 is a multi-center, open-label, Phase 1 study evaluating the safety and feasibility of dosing patients with metastatic castration resistant prostate cancer (mCRPC) with CART-PSMA-TGFβRDN (NCT04227275). Methods: This is a 3+3 dose escalation study to determine the recommended phase 2 dose and schedule of CART-PSMA-TGFβRDN cells following lymphodepleting chemotherapy with cyclophosphamide and fludarabine. Single and fractionated doses are being evaluated. A cohort expansion will enroll patients to further explore the safety of the selected dose and schedule. Results: As of January 2021, 6 patients (pts) have been treated. Two pts were treated in the first dose level (1-3 x107 transduced T cells (TDN)). Four pts were treated in the second dose level (1-3 x 108 TDN with fractionated dosing). AEs occurring in ≥50 % of pts included cytokine release syndrome (CRS), anemia, thrombocytopenia, increased creatinine, nausea, fatigue, pyrexia and dehydration. No DLTs occurred in the 1st dose level. Four pts in the 2nd dose level developed CRS (3 Gr 1 and 1 Gr 2). One pt developed rapid G2 CRS that progressed to Gr 5 encephalopathy and Gr 5 multi-organ failure. Ferritin levels peaked at 56,974 ng/ml (baseline 2,903 ng/mL) despite aggressive immunosuppressive therapy including tocilizumab, dexamtheasone and anakinra. The post infusion cytokine profile indicated elevations in IL-1RA, TNF-alpha, VEGF, IL-10, MIP-1b, IFN-gamma, GM-CSF and notably lower levels of IL6 compared to published reports of CD19 CART-mediated CRS. Autopsy findings were consistent with HLH/MAS, confirming overactivity of the monocyte/macrophage compartment. Based on these observations, a modified immune toxicity management strategy that includes prophylactic anakinra (an IL1R antagonist) was instituted. Preliminary evidence of clinical activity of CART-PSMA-TGFβRDN was noted in the 2nd dose level. Two of 3 pts with 1 month follow-up demonstrated PSA decreases from baseline (1 with >95% decrease, 1 with >50% decrease). Both pts had stable disease per RECIST v1.1. A third pt with only 1 week follow-up had a 40% PSA decrease. Additional data analyses from all infused patients are ongoing and data from pts managed with modified immune toxicity management will be presented. Conclusions: Initial data indicates a unique immune toxicity profile and the potential for anti-tumor activity in mCRPC pts treated with CART-PSMA-TGFβRDN. Modified immune toxicity management could lead to identification of a manageable safety profile and therapeutically active dose. Clinical trial information: NCT04227275.

A phase 1/2, open-label, dose-escalation, safety and tolerability study of NC410 in subjects with advanced or metastatic solid tumors

TPS2659

Background: Leukocyte-Associated Immunoglobulin-like Receptor (LAIR)-1 and LAIR-2 are members of the Leukocyte Receptor Complex (LRC) (An & Brodsky, 2016). LAIR-1 is a co-inhibitory receptor expressed on several subsets of immune cells, and functions to delimit immune responses (Meyaard et al., 1997). LAIR-2 is a secreted protein with homology to the transmembrane protein LAIR-1 (Lebbink et al., 2008). In cancer, it is hypothesized that LAIR-1 expression on several subsets of leukocytes prevents optimal immune responses by limiting both innate and adaptive immune functionality. LAIR-1 serves to suppress anti-tumor immunity through the inhibition of stimulatory signaling pathways. Specifically, LAIR-1 is a checkpoint and adhesion receptor on T cells that limits T cell activation and increases adhesion to collagens (Meyaard, 2008). LAIR-2 is capable of blocking LAIR-1 functional interactions with ligands, resulting in improved immune function on multiple immune cell subsets. Dysregulation of LAIR-1 ligands in the tumor microenvironment results in excessive production of collagens and complement C1q as well as altered forms of collagens, that leads to immune inhibition through binding to LAIR-1+ immune cells. NC410 is a dimeric form of the LAIR-2 protein fused to a human Fc domain of the immunoglobulin (Ig) subtype IgG1. The rationale for developing NC410 as a cancer therapeutic is based on nonclinical data demonstrating LAIR-1 signaling blockade can improve the immune response. Because LAIR-2 binds to ligands shared with LAIR-1 with increased affinity, NC410 acts as a decoy receptor for LAIR-1 ligands releasing suppression from myeloid cells and T cells and promoting anti-tumor immunity. NC410 may also mediate remodeling of the tumor extracellular matrix, further contributing to anti-tumor activity. Methods: This is a multi-center, first in human, phase 1/2, open-label, single-armed study to determine the safety and tolerability, define maximum tolerated dose (MTD) and/or pharmacologically active dose, assess preliminary efficacy, and explore predictive and pharmacodynamic biomarkers of NC410 in subjects with advanced or metastatic solid tumors. Key eligibility criteria include measurable disease based on RECIST v1.1 and being able to consent for collection of biopsies at screening and on treatment. Phase 1 is a classic 3+3 dose escalation design to determine the safety, tolerability, DLT, MTD and recommended phase 2 dose (RP2D) (NCT04408599). Ongoing exploratory analyses include the assessment of predictive biomarkers associated with treatment benefit, and pharmacodynamic markers associated with study drug activity. Phase 2 is going to enroll ovarian, colorectal, NSCLC, H&N, and gastric carcinomas and other tumors depending on biomarker data available from the Phase 1 part of the study. Clinical trial information: 04408599.

Characterization of cytokine release syndrome (CRS) following treatment with tebentafusp in patients (pts) with previously treated (2L+) metastatic uveal melanoma (mUM)

9531

Background: Cytokine-mediated adverse events (AEs) are commonly reported in pts treated with T cell engaging therapies. Tebentafusp (tebe), a bispecific consisting of an affinity-enhanced T cell receptor fused to an anti-CD3 effector that can redirect T cells to target gp100+ cells, has shown an overall survival benefit for pts with untreated mUM in a Ph3 trial (NCT03070392). Here we reviewed the incidence, kinetics, and outcome of CRS in tebe-treated pts on the IMCgp100-102 trial of 2L+ pts with mUM (NCT02570308). Methods: 127 HLA-A*02:01+ 2L+ mUM pts were treated with tebe at the RP2D of 68mcg following intra-patient dose escalation of 20 mcg dose 1 and 30 mcg dose 2. Pts were monitored overnight to allow management of hypotension and other cytokine-related AEs. Because the rate of severe CRS was low in Ph1, prophylactic corticosteroids, antihistamines or acetaminophen were not mandated. CRS was evaluated post-hoc according to ASTCT Consensus Grading criteria [1]. Circulating cytokines in serum were measured before and at 8hr and 12-24hr after dosing for the 1st, 3rd and 4th doses (n=105). This analysis was conducted on the primary analysis snapshot dated 04Jun20. Results: The most frequent treatment-related AEs that were likely cytokine-mediated included fever (80%), chills (64%), nausea (59%), hypotension (41%) and hypoxia (4%). In a post-hoc review using ASTCT criteria, 86% of pts (n=109) had any grade CRS. The majority of these 109 pts had either grade (G) 1 (n=42; 33%) or G2 (n=62; 49%), with few G3 (n=4; 3.1%), one G4 (0.8%), and no deaths. Onset of CRS began within 24 hours of administration and G≥2 hypotension or hypoxia typically resolved within 2 days of onset. Most CRS events occurred after the first 3 doses with a marked reduction in the frequency and severity of CRS thereafter; G3-4 CRS was limited to first two doses. Only 2 pts discontinued tebe due to CRS (1 G3 and 1 G4). Treatment of G≥2 CRS included iv fluids (n=45), iv steroids (n=18), oxygen (n=8), and vasopressor use (n=2). No pts received tocilizumab. Tebe induced a transient increase in peripheral cytokines, including IFNγ, IL-10, IL-6 and TNFα, within hours of tebe dosing, which were several fold higher in pts with CRS compared to pts without CRS. Higher levels of TNFα trended with severity of CRS. Conclusions: CRS, a common AE observed with all T cell engaging therapies, was frequently observed within 24 hours of initial tebe treatment. Most CRS events were mild or moderate in severity even without the use of prophylactic premedications, were reversible with standard management strategies, decreased in frequency and severity with subsequent doses, and rarely led to treatment discontinuation. Pts with CRS tended to have greater increases in serum cytokines, consistent with tebe’s proposed mechanism of action. [1] Lee, DW et al. Biol Blood Marrow Transplant 2019. Clinical trial information: NCT02570308.

A phase 1 dose-escalation study of intravenously (IV) administered TAK-676, a novel STING agonist, alone and in combination with pembrolizumab in patients (pts) with advanced or metastatic solid tumors

TPS2670

Background: Immuno-oncology therapies, including immune checkpoint inhibitors (CPIs), are revolutionizing cancer treatment. However, primary and secondary resistance to CPIs remains a significant challenge. CPI resistance has been associated with reduced interferon (IFN) signaling, altered antigen presentation, and an immunosuppressive tumor phenotype. Stimulating innate immune cells to develop a proinflammatory tumor environment that activates IFN signaling and downstream adaptive antitumor immune mechanisms is predicted to overcome such resistance. Stimulator of Interferon Genes (STING) is a key mediator of type 1 IFN-dependent innate immune modulation. Most STING agonists evaluated clinically have required intratumoral administration, which has significant logistical challenges and excludes many pts whose tumors are not accessible for injection. TAK-676 is a novel STING agonist under clinical investigation as an IV administered systemic therapy in pts with solid tumors. Methods: The primary objective of this study is to determine the safety and tolerability of TAK-676 alone and in combination with pembrolizumab. Secondary objectives are to: determine the pharmacologically active dose and recommended phase 2 dose; characterize TAK-676 pharmacokinetics; assess preliminary antitumor activity; and assess STING agonism gene signature induction. An exploratory objective is to assess immune cell activation and clinical response. The study comprises a single-pt safety lead-in with single-agent (SA) TAK-676 0.1 mg IV, followed by dose escalation using Bayesian Logistic Regression Model design. Dose escalation will start in the combination arm when ≥2 dose levels in the SA arm have been evaluated and considered safe. In both arms, pts will receive TAK-676 on days 1, 8, and 15 in 21-day cycles for up to 1 year. In the combination arm, pts will also receive pembrolizumab 200 mg IV on day 1 of each cycle. Adult pts with histologically confirmed advanced or metastatic solid tumors who have no standard therapeutic options or are intolerant to them, with an Eastern Cooperative Oncology Group (ECOG) performance status 0–1, and ≥1 Response Evaluation Criteria in Solid Tumors (RECIST) v.1.1- evaluable lesion are eligible; pts with tumors that have relapsed, are refractory or naïve to anti-programmed death 1 (PD-1) or anti-programmed death ligand 1 (PD-L1) therapy are eligible for the combination arm. Planned enrollment is ̃76 pts; recruitment is ongoing. Clinical trial information: NCT04420884.

Phase I study investigating the safety of stereotactic body radiotherapy (SBRT) with anti-PD-1 and anti-IL-8 for the treatment of multiple metastases in advanced solid tumors

TPS2681

Background: Anti-PD-(L)1 immunotherapy improves outcomes for patients across various cancers; however, many patients do not benefit. Previous studies combining multi-site SBRT with anti-PD1 have confirmed feasibility and revealed induction of interferon signaling by SBRT. Elevated levels of serum IL8 (sIL8) associate with lack of response to anti-PD1 and we have observed that elevated IL8 is strongly associated with lack of response to immunotherapy and SBRT combinations. Overcoming IL8 induced epithelial-mesenchymal transitioning and trafficking of myeloid derived suppressor cells in tumor microenvironment therefore represents a promising strategy to overcome resistance. BMS-986253 is a fully human neutralizing antibody that binds to sIL8. The combination of BMS-986253 and nivolumab was safe in patients with advanced solid tumors. The present study aims to evaluate safety and preliminary efficacy of combining BMS-986253 with nivolumab and SBRT in patients with advanced solid tumors, Melanoma (MEL) and Renal Cell Carcinoma (RCC). Methods: This is a phase 1 open label single arm study (CT.gov: NCT04572451) which will include safety and efficacy cohorts. Patients will receive SBRT in 1-4 tumor lesions, in 3 or 5 fractions, at the total of 30 or 45 or 50 Gy based on the irradiated organ site. This will be followed by intravenous (IV) nivolumab (480mg q4 weeks (W)) and IV BMS-986253 (2400mg q2W) within seven days of completing SBRT. In the initial safety portion of the clinical trial, we will include 30 patients with advanced/metastatic solid tumors in order to evaluate safety. The primary endpoint of dose limiting toxicity will be assessed by continual Bayesian monitoring. The toxicities will be attributed to combination of SBRT/Immunotherapy as opposed to individual components. The secondary objective of the study is efficacy with an endpoint of objective response rate (ORR) as assessed by RECIST v1.1 in Mel and RCC. We will include 20 patients with MEL and RCC and compare against a historical benchmark of 20% ORR as sufficient signal of activity for further study. ORR will be assessed for association with serum IL-8 levels and radiation-induced changes in peripheral blood T cell populations. Clinical trial information: NCT04572451.

Immunogenomic determinants of tumor microenvironment correlate with survival in high-risk neuroblastoma

Background:

Tumor-infiltrating CD8+ T cells and neoantigens are predictors of a favorable prognosis and response to immunotherapy in adult cancer, but little is known about their role in pediatric malignancies. Here, we analyzed the prognostic strength of T cell-inflamed (Tinfl) expression and neoantigen load (neo) in high-risk neuroblastoma (NBL). We investigated transcriptional programs associated with the non-T cell-inflamed (non-Tinfl) phenotype for mechanisms of immune exclusion.

Methods:

Using a defined Tinfl gene expression signature, we categorized high-risk NBL from the TARGET (Therapeutically Applicable Research to Generate Effective Treatments, n=123) and the GMKF (Gabriella Miller Kids First, n=48) programs into non-Tinfl, Tinfl, and intermediate groups. Cox proportional hazard models were used to test the association between survival and tumor group, neo, MYCN amplification. Pathways activated in non-Tinfl vs. Tinfl tumors were identified.

Results:

Patients with high-risk Tinfl tumors showed improved overall survival (OS) compared to those with non-Tinfl tumors (P<0.05), independent of MYCN amplification, in both TARGET and GMKF. Higher neo was associated with better event-free survival and OS (P<0.005) and was independent of Tinfl. Activation of MYCN, ASCL1, SOX11, and KMT2A was inversely correlated with the Tinfl signature in both cohorts.

Conclusions:

Our results indicate that tumors from children with high-risk NBL harboring a strong Tinfl signature have a favorable clinical outcome, and neo is a prognosis predictor, independent of Tinfl. Strategies to target SOX11 and other signaling pathways associated with non-Tinfl tumors should be pursued as potential immune-potentiating interventions.

First-in-Human Phase I Study of ABBV-085, an Antibody-Drug Conjugate Targeting LRRC15, in Sarcomas and Other Advanced Solid Tumors

PURPOSE

Leucine-rich repeat containing 15 (LRRC15) is expressed on stromal fibroblasts in the tumor microenvironment of multiple solid tumor types and may represent an interesting target for therapy, particularly in patients with sarcomas where LRRC15 is also expressed by malignant cells. ABBV-085 is a monomethyl auristatin-E antibody-drug conjugate that targets LRRC15 and showed antineoplastic efficacy in preclinical experiments. Herein, we report findings of ABBV-085 monotherapy or combination therapy in adult patients with sarcomas and other advanced solid tumors.

PATIENTS AND METHODS

This first-in-human phase I study (NCT02565758) assessed ABBV-085 safety, pharmacokinetics/pharmacodynamics, and preliminary antitumor activity. The study consisted of two parts: dose escalation and dose expansion. ABBV-085 was administered by intravenous infusion at 0.3 to 6.0 mg/kg every 14 days.

RESULTS

In total, 85 patients were enrolled; 45 patients received the recommended expansion dose of 3.6 mg/kg ABBV-085 monotherapy, including 10 with osteosarcoma and 10 with undifferentiated pleomorphic sarcoma (UPS). Most common treatment-related adverse events were fatigue, nausea, and decreased appetite. The overall response rate for patients with osteosarcoma/UPS treated at 3.6 mg/kg was 20%, including four confirmed partial responses. No monotherapy responses were observed for other advanced cancers treated at 3.6 mg/kg. One patient treated with ABBV-085 plus gemcitabine achieved partial response.

CONCLUSIONS

ABBV-085 appeared safe and tolerable at a dose of 3.6 mg/kg every 14 days, with preliminary antitumor activity noted in patients with osteosarcoma and UPS. Given the high unmet need in these orphan malignancies, further investigation into targeting LRRC15 in these sarcomas may be warranted.

High Throughput Multi-Omics Approaches for Clinical Trial Evaluation and Drug Discovery

High throughput single cell multi-omics platforms, such as mass cytometry (cytometry by time-of-flight; CyTOF), high dimensional imaging (>6 marker; Hyperion, MIBIscope, CODEX, MACSima) and the recently evolved genomic cytometry (Citeseq or REAPseq) have enabled unprecedented insights into many biological and clinical questions, such as hematopoiesis, transplantation, cancer, and autoimmunity. In synergy with constantly adapting new single-cell analysis approaches and subsequent accumulating big data collections from these platforms, whole atlases of cell types and cellular and sub-cellular interaction networks are created. These atlases build an ideal scientific discovery environment for reference and data mining approaches, which often times reveals new cellular disease networks. In this review we will discuss how combinations and fusions of different -omic workflows on a single cell level can be used to examine cellular phenotypes, immune effector functions, and even dynamic changes, such as metabolomic state of different cells in a sample or even in a defined tissue location. We will touch on how pre-print platforms help in optimization and reproducibility of workflows, as well as community outreach. We will also shortly discuss how leveraging single cell multi-omic approaches can be used to accelerate cellular biomarker discovery during clinical trials to predict response to therapy, follow responsive cell types, and define novel druggable target pathways. Single cell proteome approaches already have changed how we explore cellular mechanism in disease and during therapy. Current challenges in the field are how we share these disruptive technologies to the scientific communities while still including new approaches, such as genomic cytometry and single cell metabolomics.

Case Report: Single Dose Anti-PD1 in a Patient With Metastatic Melanoma and Cardiac Allograft

Background

Immune-checkpoint inhibition has improved outcomes in metastatic melanoma. However, limited data describes the safety and efficacy of this treatment in the setting of cardiac allograft. Emerging translational and clinical evidence suggests that the majority of the benefit from these therapies is driven by the initial dose(s), and that attenuated dosing schedules may be as effective as continuous treatment.

Case presentation

We present a case vignette of a cardiac transplant recipient with metastatic melanoma who experienced six months of clinical benefit after one dose of pembrolizumab and did not suffer allograft rejection.

Conclusion

This case adds to the current available literature on the administration of checkpoint inhibitors in patients with cardiac allografts. Further, it explores potential markers of immunotherapy response and supports the potential of shorter or individualized immune-checkpoint blockade dosing strategies.

Radiation treatment planning study to investigate feasibility of delivering Immunotherapy in Combination with Ablative Radiosurgery to Ultra-High DoSes (ICARUS)

PURPOSE

Immune checkpoint inhibitors improve survival in metastatic diseases for some cancers. Multisite SBRT with pembrolizumab (SBRT + Pembro) was shown to be safe with promising local control using biologically effective doses (BEDs) = 95-120 Gy. Increased BED may improve response rate; however, SBRT doses are limited by surrounding organs at risk (OARs). The purpose of this work was to develop and validate methods for safe delivery of ultra-high doses of radiation (BED₁₀  > 300) to be used in future clinical trials.

METHODS AND MATERIALS

The radiation plans from 15 patients enrolled on a phase I trial of SBRT + pembro were reanalyzed. Metastatic disease sites included liver (8/15), inguinal region (1/15), pelvis (2/15), lung (1/15), abdomen (1/15), spleen (1/15), and groin (1/15). Gross tumor volumes (GTVs) ranged from 80 to 708 cc. Following the same methodology used in the Phase I trial on which these patients were treated, GTVs > 65 cc were contracted to a 65 cc subvolume (SubGTV) resulting in only a portion of the GTV receiving prescription dose. Volumetric modulated arc therapy (VMAT) was used to plan treatments BED₁₀  = 360 Gy. Plans utilizing both 6FFF and 10FFF beams were compared to clinical plans delivering BED₁₀  = 112.50 Gy. The target primary goal was V100% > 95% with a secondary goal of V70% > 99% and OAR objectives per the trial. To demonstrate feasibility, plans were delivered to a diode array phantom and evaluated for fidelity using gamma analysis.

RESULTS

All 30 plans met the secondary coverage goal and satisfied all OAR constraints. The primary goal was achieved in 12/15 of the 6FFF plans and 13/15 of the 10FFF plans. Average gamma analysis passing rate using criteria of 3% dose difference and 3, 2, and 1 mm were 99.1  ±  1.0%, 98.5  ±  1.6%, and 95.1  ±  3.8%, respectively.

CONCLUSION

Novel VMAT planning approaches with clinical treatment planning software and linear accelerators prove capable of delivering radiation doses in excess of 360 Gy BED₁₀ to tumor subvolumes, while maintaining safe OAR doses.

Phase I study of ABBV-428, a mesothelin-CD40 bispecific, in patients with advanced solid tumors

BACKGROUND

CD40 agonist immunotherapy can potentially license antigen-presenting cells to promote antitumor T-cell activation and re-educate macrophages to destroy tumor stroma. Systemic administration of CD40 agonists has historically been associated with considerable toxicity, providing the rationale for development of tumor-targeted immunomodulators to improve clinical safety and efficacy. This phase I study assessed the safety, tolerability, preliminary antitumor activity, and preliminary biomarkers of ABBV-428, a first-in-class, mesothelin-targeted, bispecific antibody designed for tumor microenvironment-dependent CD40 activation with limited systemic toxicity.

METHODS

ABBV-428 was administered intravenously every 2 weeks to patients with advanced solid tumors. An accelerated titration (starting at a 0.01 mg/kg dose) and a 3+3 dose escalation scheme were used, followed by recommended phase II dose cohort expansions in ovarian cancer and mesothelioma, tumor types associated with high mesothelin expression.

RESULTS

Fifty-nine patients were treated at doses between 0.01 and 3.6 mg/kg. The maximum tolerated dose was not reached, and 3.6 mg/kg was selected as the recommended phase II dose. Seven patients (12%) reported infusion-related reactions. Treatment-related grade ≥3 treatment-emergent adverse events were pericardial effusion, colitis, infusion-related reaction, and pleural effusion (n=1 each, 2%), with no cytokine release syndrome reported. The pharmacokinetic profile demonstrated roughly dose-proportional increases in exposure from 0.4 to 3.6 mg/kg. Best response was stable disease in 9/25 patients (36%) treated at the recommended phase II dose. CD40 receptor occupancy >90% was observed on peripheral B-cells starting from 0.8 mg/kg; however, no consistent changes from baseline in intratumoral CD8+ T-cells, programmed death ligand-1 (PD-L1+) cells, or immune-related gene expression were detected post-ABBV-428 treatment (cycle 2, day 1). Mesothelin membrane staining showed greater correlation with progression-free survival in ovarian cancer and mesothelioma than in the broader dose escalation population.

CONCLUSIONS

ABBV-428 monotherapy exhibited dose-proportional pharmacokinetics and an acceptable safety profile, particularly for toxicities characteristic of CD40 agonism, illustrating that utilization of a tumor-targeted, bispecific antibody can improve the safety of CD40 agonism as a therapeutic approach. ABBV-428 monotherapy had minimal clinical activity in dose escalation and in a small expansion cohort of patients with advanced mesothelioma or ovarian cancer.

TRIAL REGISTRATION NUMBER

NCT02955251.

Transcriptional analysis of metastatic uveal melanoma survival nominates NRP1 as a therapeutic target

Uveal melanoma is a rare form of melanoma with particularly poor outcomes in the metastatic setting. In contrast with cutaneous melanoma, uveal melanoma lacks BRAF mutations and demonstrates very low response rates to immune-checkpoint blockade. Our objectives were to study the transcriptomics of metastatic uveal melanoma with the intent of assessing gene pathways and potential molecular characteristics that might be nominated for further exploration as therapeutic targets. We initially analyzed transcriptional data from The Cancer Genome Atlas suggesting PI3K/mTOR and glycolysis as well as IL6 associating with poor survival. From tumor samples collected in a prospective phase II trial (A091201), we performed a transcriptional analysis of human metastatic uveal melanoma observing a novel role for epithelial-mesenchymal transition associating with survival. Specifically, we nominate and describe initial functional validation of neuropillin-1 from uveal melanoma cells as associated with poor survival and as a mediator of proliferation and migration for uveal melanoma in vitro. These results immediately nominate potential next steps in clinical research for patients with metastatic uveal melanoma.

Model Informed Dosing Regimen and Phase I Results of the Anti-PD-1 Antibody Budigalimab (ABBV-181)

Budigalimab is a humanized, recombinant, Fc mutated IgG1 monoclonal antibody targeting programmed cell death 1 (PD‐1) receptor, currently in phase I clinical trials. The safety, efficacy, pharmacokinetics (PKs), pharmacodynamics (PDs), and budigalimab dose selection from monotherapy dose escalation and multihistology expansion cohorts were evaluated in patients with previously treated advanced solid tumors who received budigalimab at 1, 3, or 10 mg/kg intravenously every 2 weeks (Q2W) in dose escalation, including Japanese patients that received 3 and 10 mg/kg Q2W. PK modeling and PK/PD assessments informed the dosing regimen in expansion phase using data from body‐weight‐based dosing in the escalation phase, based on which patients in the multihistology expansion cohort received flat doses of 250 mg Q2W or 500 mg every four weeks (Q4W). Immune‐related adverse events (AEs) were reported in 11 of 59 patients (18.6%), of which 1 of 59 (1.7%) was considered grade ≥ 3 and the safety profile of budigalimab was consistent with other PD‐1 targeting agents. No treatment‐related grade 5 AEs were reported. Four responses per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 were reported in the dose escalation cohort and none in the multihistology expansion cohort. PK of budigalimab was approximately dose proportional and sustained > 99% peripheral PD‐1 receptor saturation was observed by 2 hours postdosing, across doses. PK/PD and safety profiles were comparable between Japanese and Western patients, and exposure‐safety analyses did not indicate any trends. Observed PK and PD‐1 receptor saturation were consistent with model predictions for flat doses and less frequent regimens, validating the early application of PK modeling and PK/PD assessments to inform the recommended dose and regimen, following dose escalation.

Development and Preliminary Clinical Activity of PD-1-Guided CTLA-4 Blocking Bispecific DART Molecule

Combination immunotherapy with antibodies directed against PD-1 and CTLA-4 shows improved clinical benefit across cancer indications compared to single agents, albeit with increased toxicity. Leveraging the observation that PD-1 and CTLA-4 are co-expressed by tumor-infiltrating lymphocytes, an investigational PD-1 x CTLA-4 bispecific DART molecule, MGD019, is engineered to maximize checkpoint blockade in the tumor microenvironment via enhanced CTLA-4 blockade in a PD-1-binding-dependent manner. In vitro, MGD019 mediates the combinatorial blockade of PD-1 and CTLA-4, confirming dual inhibition via a single molecule. MGD019 is well tolerated in non-human primates, with evidence of both PD-1 and CTLA-4 blockade, including increases in Ki67+CD8 and ICOS+CD4 T cells, respectively. In the ongoing MGD019 first-in-human study enrolling patients with advanced solid tumors (NCT03761017), an analysis undertaken following the dose escalation phase revealed acceptable safety, pharmacodynamic evidence of combinatorial blockade, and objective responses in multiple tumor types typically unresponsive to checkpoint inhibitor therapy.

Improved Survival Associated with Local Tumor Response Following Multisite Radiotherapy and Pembrolizumab: Secondary Analysis of a Phase I Trial

PURPOSE

Multisite stereotactic body radiotherapy followed by pembrolizumab (SBRT+P) has demonstrated safety in advanced solid tumors (ASTs). However, no studies have examined the relationships between irradiated tumor response, SBRT-induced tumor gene expression, and overall survival (OS).

PATIENTS AND METHODS

Patients with AST received SBRT (30-50 Gy in 3-5 fractions) to two to four metastases followed by pembrolizumab (200 mg i.v. every 3 weeks). SBRT was prescribed to a maximum tumor volume of 65 mL. Small metastases received the complete prescribed coverage (complete-Rx), while larger metastases received partial coverage (partial-Rx). Treated metastasis control (TMC) was defined as a lack of progression for an irradiated metastasis. Landmark analysis was used to assess the relationship between TMC and OS. Thirty-five biopsies were obtained from 24 patients: 19 pre-SBRT and 16 post-SBRT (11 matched) prior to pembrolizumab and were analyzed via RNA microarray.

RESULTS

Sixty-eight patients (139 metastases) were enrolled with a median follow-up of 10.4 months. One-year TMC was 89.5% with no difference between complete-Rx or partial-Rx. On multivariable analysis, TMC was independently associated with a reduced risk for death (HR, 0.36; 95% confidence interval, 0.17-0.75; P = 0.006). SBRT increased expression of innate and adaptive immune genes and concomitantly decreased expression of cell cycle and DNA repair genes in the irradiated tumors. Elevated post-SBRT expression of DNASE1 correlated with increased expression of cytolytic T-cell genes and irradiated tumor response.

CONCLUSIONS

In the context of SBRT+P, TMC independently correlates with OS. SBRT impacts intratumoral immune gene expression associated with TMC. Randomized trials are needed to validate these findings.

Tumor neoantigenicity assessment with CSiN score incorporates clonality and immunogenicity to predict immunotherapy outcomes

Lack of responsiveness to checkpoint inhibitors is a central problem in the modern era of cancer immunotherapy. Tumor neoantigens are critical targets of the host antitumor immune response, and their presence correlates with the efficacy of immunotherapy treatment. Many studies involving assessment of tumor neoantigens principally focus on total neoantigen load, which simplistically treats all neoantigens equally. Neoantigen load has been linked with treatment response and prognosis in some studies but not others. We developed a Cauchy-Schwarz index of Neoantigens (CSiN) score to better account for the degree of concentration of immunogenic neoantigens in truncal mutations. Unlike total neoantigen load determinations, CSiN incorporates the effect of both clonality and MHC binding affinity of neoantigens when characterizing tumor neoantigen profiles. By analyzing the clinical responses in 501 treated patients with cancer (with most receiving checkpoint inhibitors) and the overall survival of 1978 patients with cancer at baseline, we showed that CSiN scores predict treatment response to checkpoint inhibitors and prognosis in patients with melanoma, lung cancer, and kidney cancer. CSiN score substantially outperformed prior genetics-based prediction methods of responsiveness and fills an important gap in research involving assessment of tumor neoantigen burden.

A case of dual-mechanism immune-related anaemia in a patient with metastatic melanoma treated with nivolumab and ipilimumab

Background

The combination of the immune checkpoint inhibitors (ICIs) ipilimumab and nivolumab is a mainstay of treatment for selected patients with metastatic melanoma. This combination also results in more frequent immune-related adverse events (irAEs) than either ICI alone. These irAEs can be severe and their pathogenesis is poorly understood.

Case presentation

We report a case of a woman with metastatic melanoma, treated with combined ipilimumab and nivolumab, who developed severe anaemia. While initial workup revealed autoimmune haemolytic anaemia, the anaemia persisted despite corticosteroids and paradoxical reticulocytopenia was observed. Bone marrow biopsy demonstrated a CD8⁺ T cell-mediated destruction of the red cell precursors implying concurrent pure red cell aplasia. Both processes resolved after the addition of cyclosporine A.

Conclusions

This report describes a rare case of two concurrent mechanisms of haematological irAE in a patient treated with combined ICI therapy. Successful treatment resulted only after the second underlying mechanism of toxicity was uncovered. Prompt recognition of these unusual presentations of rare irAEs is now key to effective irAE management.

Molecular correlates and therapeutic targets in T cell-inflamed versus non-T cell-inflamed tumors across cancer types

BACKGROUND

The T cell-inflamed tumor microenvironment, characterized by CD8 T cells and type I/II interferon transcripts, is an important cancer immunotherapy biomarker. Tumor mutational burden (TMB) may also dictate response, and some oncogenes (i.e., WNT/β-catenin) are known to mediate immunosuppression.

METHODS

We performed an integrated multi-omic analysis of human cancer including 11,607 tumors across multiple databases and patients treated with anti-PD1. After adjusting for TMB, we correlated the T cell-inflamed gene expression signature with somatic mutations, transcriptional programs, and relevant proteome for different immune phenotypes, by tumor type and across cancers.

RESULTS

Strong correlations were noted between mutations in oncogenes and tumor suppressor genes and non-T cell-inflamed tumors with examples including IDH1 and GNAQ as well as less well-known genes including KDM6A, CD11c, and genes with unknown functions. Conversely, we observe genes associating with the T cell-inflamed phenotype including VHL and PBRM1. Analyzing gene expression patterns, we identify oncogenic mediators of immune exclusion across cancer types (HIF1A and MYC) as well as novel examples in specific tumors such as sonic hedgehog signaling, hormone signaling and transcription factors. Using network analysis, somatic and transcriptomic events were integrated. In contrast to previous reports of individual tumor types such as melanoma, integrative pan-cancer analysis demonstrates that most non-T cell-inflamed tumors are influenced by multiple signaling pathways and that increasing numbers of co-activated pathways leads to more highly non-T cell-inflamed tumors. Validating these analyses, we observe highly consistent inverse relationships between pathway protein levels and the T cell-inflamed gene expression across cancers. Finally, we integrate available databases for drugs that might overcome or augment the identified mechanisms.

CONCLUSIONS

These results nominate molecular targets and drugs potentially available for further study and potential immediate translation into clinical trials for patients with cancer.

Conserved Interferon-γ Signaling Drives Clinical Response to Immune Checkpoint Blockade Therapy in Melanoma

We analyze the transcriptome of baseline and on-therapy tumor biopsies from 101 patients with advanced melanoma treated with nivolumab (anti-PD-1) alone or combined with ipilimumab (anti-CTLA-4). We find that T cell infiltration and interferon-γ (IFN-γ) signaling signatures correspond most highly with clinical response to therapy, with a reciprocal decrease in cell-cycle and WNT signaling pathways in responding biopsies. We model the interaction in 58 human cell lines, where IFN-γ in vitro exposure leads to a conserved transcriptome response unless cells have IFN-γ receptor alterations. This conserved IFN-γ transcriptome response in melanoma cells serves to amplify the antitumor immune response. Therefore, the magnitude of the antitumor T cell response and the corresponding downstream IFN-γ signaling are the main drivers of clinical response or resistance to immune checkpoint blockade therapy.

Toll-Like Receptor 9 Agonists in Cancer

Toll-like receptor 9 (TLR9) is a pattern recognition receptor that is predominantly located intracellularly in immune cells, including dendritic cells, macrophages, natural killer cells, and other antigen-presenting cells (APC). The primary ligands for TLR9 receptors are unmethylated cytidine phosphate guanosine (CpG) oligodinucleotides (ODN). TLR9 agonists induce inflammatory processes that result in the enhanced uptake and killing of microorganisms and cancer cells as well as the generation of adaptive immune responses. Preclinical studies of TLR9 agonists suggested efficacy both as monotherapy and in combination with several agents, which led to clinical trials in patients with advanced cancer. In these studies, intravenous, intratumoral, and subcutaneous routes of administration have been tested; with anti-tumor responses in both treated and untreated metastatic sites. TLR9 agonist monotherapy is safe, although efficacy is minimal in advanced cancer patients; conversely, combinations appear to be more promising. Several ongoing phase I and II clinical trials are evaluating TLR9 agonists in combination with a variety of agents including chemotherapy, radiotherapy, targeted therapy, and immunotherapy agents. In this review article, we describe the distribution, structure and signaling of TLR9; discuss the results of preclinical studies of TLR9 agonists; and review ongoing clinical trials of TLR9 agonists singly and in combination in patients with advanced solid tumors.

Perspectives in melanoma: meeting report from the "Melanoma Bridge" (December 5th-7th, 2019, Naples, Italy)

The melanoma treatment landscape changed in 2011 with the approval of the first anti-cytotoxic T-lymphocyte-associated protein (CTLA)-4 checkpoint inhibitor and of the first BRAF-targeted monoclonal antibody, both of which significantly improved overall survival (OS). Since then, improved understanding of the tumor microenvironment (TME) and tumor immune-evasion mechanisms has resulted in new approaches to targeting and harnessing the host immune response. The approval of new immune and targeted therapies has further improved outcomes for patients with advanced melanoma and other combination modalities are also being explored such as chemotherapy, radiotherapy, electrochemotherapy and surgery. In addition, different strategies of drugs administration including sequential or combination treatment are being tested. Approaches to overcome resistance and to potentiate the immune response are being developed. Increasing evidence emerges that tissue and blood-based biomarkers can predict the response to a therapy. The latest findings in melanoma research, including insights into the tumor microenvironment and new biomarkers, improved understanding of tumor immune response and resistance, novel approaches for combination strategies and the role of neoadjuvant and adjuvant therapy, were the focus of discussions at the Melanoma Bridge meeting (5-7 December, 2019, Naples, Italy), which are summarized in this report.