Circulating microRNA-155-3p levels predicts response to first line immunotherapy in patients with metastatic renal cell carcinoma

Predictive biomarkers of response to immune checkpoint-based therapies (ICI) remain a critically unmet need in the management of advanced renal cell carcinoma (RCC). The complex interplay of the tumour microenvironment (TME) and the circulating immune response has proven to be challenging to decipher. MicroRNAs have gained increasing attention for their role in post-transcriptional gene expression regulation, particularly because they can have immunomodulatory properties. We evaluated the presence of immune-specific extracellular vesicle (EV) microRNAs in the plasma of patients with metastatic RCC (mRCC) prior to initiation of ICI. We found significantly lower levels of microRNA155-3p (miR155) in responders to ICI, when compared to non-responders. This microRNA has unique immunomodulatory properties, thus providing potential biological rationale for our findings. Our results support further work in exploring microRNAs as potential biomarkers of response to immunotherapy.

Prediction of plasma ctDNA fraction and prognostic implications of liquid biopsy in advanced prostate cancer

No consensus strategies exist for prognosticating metastatic castration-resistant prostate cancer (mCRPC). Circulating tumor DNA fraction (ctDNA%) is increasingly reported by commercial and laboratory tests but its utility for risk stratification is unclear. Here, we intersect ctDNA%, treatment outcomes, and clinical characteristics across 738 plasma samples from 491 male mCRPC patients from two randomized multicentre phase II trials and a prospective province-wide blood biobanking program. ctDNA% correlates with serum and radiographic metrics of disease burden and is highest in patients with liver metastases. ctDNA% strongly predicts overall survival, progression-free survival, and treatment response independent of therapeutic context and outperformed established prognostic clinical factors. Recognizing that ctDNA-based biomarker genotyping is limited by low ctDNA% in some patients, we leverage the relationship between clinical prognostic factors and ctDNA% to develop a clinically-interpretable machine-learning tool that predicts whether a patient has sufficient ctDNA% for informative ctDNA genotyping (available online: https://www.ctDNA.org ). Our results affirm ctDNA% as an actionable tool for patient risk stratification and provide a practical framework for optimized biomarker testing.

A generalizable machine learning framework for classifying DNA repair defects using ctDNA exomes

Specific classes of DNA damage repair (DDR) defect can drive sensitivity to emerging therapies for metastatic prostate cancer. However, biomarker approaches based on DDR gene sequencing do not accurately predict DDR deficiency or treatment benefit. Somatic alteration signatures may identify DDR deficiency but historically require whole-genome sequencing of tumour tissue. We assembled whole-exome sequencing data for 155 high ctDNA fraction plasma cell-free DNA and matched leukocyte DNA samples from patients with metastatic prostate or bladder cancer. Labels for DDR gene alterations were established using deep targeted sequencing. Per sample mutation and copy number features were used to train XGBoost ensemble models. Naive somatic features and trinucleotide signatures were associated with specific DDR gene alterations but insufficient to resolve each class. Conversely, XGBoost-derived models showed strong performance including an area under the curve of 0.99, 0.99 and 1.00 for identifying BRCA2, CDK12, and mismatch repair deficiency in metastatic prostate cancer. Our machine learning approach re-classified several samples exhibiting genomic features inconsistent with original labels, identified a metastatic bladder cancer sample with a homozygous BRCA2 copy loss, and outperformed an existing exome-based classifier for BRCA2 deficiency. We present DARC Sign (DnA Repair Classification SIGNatures); a public machine learning tool leveraging clinically-practical liquid biopsy specimens for simultaneously identifying multiple types of metastatic prostate cancer DDR deficiencies. We posit that it will be useful for understanding differential responses to DDR-directed therapies in ongoing clinical trials and may ultimately enable prospective identification of prostate cancers with phenotypic evidence of DDR deficiency.

Machine-learning to predict utility of circulating tumor DNA (ctDNA) for somatic genotyping

232

Background: ctDNA genotyping is increasingly used to evaluate patient eligibility for genomics-driven treatments ( e.g., PARP inhibitors) in metastatic castration-resistant prostate cancer (mCRPC), but low ctDNA-fraction (ctDNA%) causes false negatives and is unpredictable. We investigated whether a machine-learning model exploiting routine clinical prognostic markers can predict if a mCRPC patient will have sufficient ctDNA% for informative ctDNA testing. Methods: We analysed plasma cell-free DNA (cfDNA) collected at baseline prior to first-line therapy from 463 consecutive mCRPC patients. ctDNA% was quantified using somatic allele frequencies and genome-wide copy number profiles via deep targeted sequencing. We built an XGBoost model (70:30 train-test split) using 18 clinical factors to predict synchronously measured ctDNA% (binary classification >2% or ≤2%, i.e., the conventional ctDNA% limit of detection for mutations employed by commercial tests), with performance evaluated using area under the curve (AUC) of receiver operating characteristics. Results: Median age was 73 (range: 45-98) and 86% of patients had ECOG 0-1. Median ctDNA% was 5% (range: 0-89%) and correlated with serum and radiographic metrics of disease burden, including total cfDNA concentration (ng/mL of plasma, reflecting cfDNA released by both normal and tumor cells; Spearman ρ=0.55), alkaline phosphatase (ALP) per upper limit of normal (ULN) ( ρ=0.46), lactate dehydrogenase (LDH) per ULN ( ρ=0.41), PSA ( ρ=0.3), presence of liver metastases, and ≥10 bone lesions. We trained an XGBoost model incorporating these and 13 additional clinical factors achieving an AUC for ctDNA >2% of 0.83 (F1 score: 0.79). SHAP interpretability scores indicated that cfDNA concentration most strongly informed prediction of ctDNA >2%, followed by ALP/ULN and PSA—consistent with our prior bivariate rank correlations—whereas features associated with initial prostate cancer diagnosis (Gleason Grade Group, de novo versus metachronous M1 disease) were less informative. Recognizing that comprehensive and standardised clinical annotation is not always available in real-world settings, we built a secondary parsimonious ctDNA%-prediction tool restricted to 8 highly informative and clinically practical factors (cfDNA concentration, ALP/ULN, LDH/ULN, PSA, albumin, ECOG, liver metastases, lung metastases) and flexible to incomplete input data, achieving a comparable AUC for ctDNA>2% of 0.76. Conclusions: Our results demonstrate the feasibility of a machine learning framework to estimate ctDNA% in patients with mCRPC. This point-of-care tool would enable prioritisation of mCRPC patients for ctDNA somatic genotyping with a predicted ctDNA >2%, versus tissue or germline-only testing in patients with a predicted ctDNA ≤2%.

Tilsotolimod Exploits the TLR9 Pathway to Promote Antigen Presentation and Type 1 IFN Signaling in Solid Tumors: A Multicenter International Phase I/II Trial (ILLUMINATE-101)

PURPOSE

Tilsotolimod is an investigational synthetic Toll-like receptor 9 (TLR9) agonist that has demonstrated antitumor activity in preclinical models. The ILLUMINATE-101 phase I study explored the safety, dose, efficacy, and immune effects of intratumoral (it) tilsotolimod monotherapy in multiple solid tumors.

PATIENTS AND METHODS

Patients with a diagnosis of refractory cancer not amenable to curative therapies received tilsotolimod in doses escalating from 8 to 32 mg into a single lesion at weeks 1, 2, 3, 5, 8, and 11. Additional patients with advanced malignant melanoma were enrolled into an expansion cohort at the 8 mg dose. Objectives included characterizing the safety, establishing the dose, efficacy, and immunologic assessment. Blood samples and tumor biopsies of injected and noninjected lesions were obtained at baseline and 24 hours after treatment for immune analyses.

RESULTS

Thirty-eight and 16 patients were enrolled into the dose escalation and melanoma expansion cohorts, respectively. Deep visceral injections were conducted in 91% of patients. No dose-limiting toxicities (DLT) or grade 4 treatment-related adverse events were observed. Biopsies 24 hours after treatment demonstrated an increased IFN pathway signature and dendritic cell maturation. Immunologic profiling revealed upregulation of IFN-signaling genes and modulation of genes for checkpoint proteins. In the dose escalation cohort, 12 (34%) of 35 evaluable patients achieved a best overall response rate (ORR) of stable disease (SD), whereas 3 (19%) of 16 evaluable patients in the melanoma cohort achieved stable disease.

CONCLUSIONS

Overall, tilsotolimod monotherapy was generally well tolerated and induced rapid, robust alterations in the tumor microenvironment. See related commentary by Punekar and Weber, p. 5007.

The 5-Hydroxymethylcytosine Landscape of Prostate Cancer

Analysis of DNA methylation is a valuable tool to understand disease progression and is increasingly being used to create diagnostic and prognostic clinical biomarkers. While conversion of cytosine to 5-methylcytosine (5mC) commonly results in transcriptional repression, further conversion to 5-hydroxymethylcytosine (5hmC) is associated with transcriptional activation. Here we perform the first study integrating whole-genome 5hmC with DNA, 5mC, and transcriptome sequencing in clinical samples of benign, localized, and advanced prostate cancer. 5hmC is shown to mark activation of cancer drivers and downstream targets. Furthermore, 5hmC sequencing revealed profoundly altered cell states throughout the disease course, characterized by increased proliferation, oncogenic signaling, dedifferentiation, and lineage plasticity to neuroendocrine and gastrointestinal lineages. Finally, 5hmC sequencing of cell-free DNA from patients with metastatic disease proved useful as a prognostic biomarker able to identify an aggressive subtype of prostate cancer using the genes TOP2A and EZH2, previously only detectable by transcriptomic analysis of solid tumor biopsies. Overall, these findings reveal that 5hmC marks epigenomic activation in prostate cancer and identify hallmarks of prostate cancer progression with potential as biomarkers of aggressive disease.

SIGNIFICANCE

In prostate cancer, 5-hydroxymethylcytosine delineates oncogene activation and stage-specific cell states and can be analyzed in liquid biopsies to detect cancer phenotypes. See related article by Wu and Attard, p. 3880.

Biallelic loss of TP53, PTEN, and RB1 in association to aggressive clinical features and poor outcomes in metastatic castration-resistant prostate cancer (mCRPC)

5055

Background: Deleterious alterations in tumor suppressor genes (TSGs) TP53, RB1, and PTEN are potential markers of small cell neuroendocrine prostate cancer (SCNP), and androgen receptor pathway inhibitor (ARPI) resistance. We examined the outcomes and clinical features of mCRPC patients (pts) harboring biallelic loss in 0, 1, 2 or all 3 TSGs. Methods: We identified 210 consecutive mCRPC pts providing ≥1 plasma cell-free DNA sample with ≥20% circulating tumor DNA fraction (ctDNA%) during their mCRPC disease course. ctDNA% ≥20% enabled sensitive characterization of biallelic TSG loss (including by homozygous deletions and mutation plus somatic loss-of-heterozygosity; LOH). Patient records were reviewed for baseline characteristics, SCNP histology, and presence of liver metastases. We investigated associations between TSG loss and the following clinical outcomes: PSA response (PSA decline ≥50% (PSA50 RR)), progression free survival (PFS) on 1L therapy, and overall survival (OS) from 1L therapy. Results: Median follow-up was 16.5 months (range: 0.4-112.4) and OS event rate was 95%. Median age at 1L mCRPC was 71 years (range: 48-98). Most pts were ECOG PS 0-1 (79%) and 13% had liver metastases. 91% received ARPI for 1L mCRPC and 7% received ARPI for castration-sensitive disease. TP53 was primarily inactivated by somatic mutation plus LOH (90%), whereas RB1 (71%) and PTEN (86%) were more commonly inactivated by homozygous deletions. Compared to pts without evidence of biallelic TSG loss, pts with loss of 3 TSGs were significantly enriched for de-novo M1 disease (86 vs. 60%, p=0.05) and liver metastases (28.5 vs. 6.8%, p<0.05). Ten pts (4.7%) had histologically confirmed SCNP and provided ctDNA at time of SCNP diagnosis. Of these, 7 (70%) had biallelic loss of ≥2 TSGs. For all pts receiving 1L therapy, loss of ≥1 TSG(s) was associated with decreased OS (HR: 1.86, 95% CI: 1.40-2.48, p<0.01) and PFS (HR:1.74, 95% CI 1.29-2.34, p<0.01) compared to pts with no biallelic TSG loss. Furthermore, a cumulative increase in the number of TSGs lost was associated with an incremental reduction in OS and PFS (Table). Conclusions: In a cohort enriched for poor prognosis (i.e. high ctDNA%), cumulative loss of TSGs is associated with aggressive disease features and poor clinical outcomes. These patients may benefit from alternative treatment intensification strategies. [Table: see text]

BMC128: A rationally designed live bacterial consortium for the potentiation of immune checkpoint therapy in solid tumors

TPS2685

Background: Immune-Checkpoint inhibitors (ICI) have transformed the treatment of solid tumors, specifically in cutaneous melanoma, clear cell renal cell carcinoma (ccRCC) and non-small cell lung cancer (NSCLC). Despite these advances, a significant proportion of patients do not respond to ICI and only a fraction of responding patients will experience durable responses. Recent reports have found that patients showing poor response to ICI are characterized by a reduced gut microbiome diversity, suggesting that the gut microbiome might affect immune activation by ICI. BMC128 is a live bacterial consortium of 4 bacterial strains predicted to induce anti-tumor immune function when given in conjunction with ICI. These strains were identified by analyzing data obtained from NSCLC and ccRCC patients presenting varied responses to ICI, using a proprietary computational discovery platform enabling high-resolution functional microbiome analysis. In pre-clinical studies, treatment with BMC128 potentiated the efficacy of ICI in breast cancer and melanoma mouse models, reducing tumor volume, increasing the number of responders, and demonstrating an increase in infiltrating immunocytes: CD4, CD8 and NK cells. Methods: In this phase I, first-in-human trial, patients with ccRCC, cutaneous melanoma and NSCLC-adenocarcinoma (EGFR/ALK wild-type), who previously progressed on PD1/PDL-1 inhibitors will be treated with BMC128 8*108 CFU BID in combination with Nivolumab at a fixed-dose of 480mg q4weeks in a 3+3 design, followed by a 9 patient expansion phase. No dose escalation is planned. The primary objective is to investigate the safety and tolerability of BMC128 in combination with Nivolumab. Enrollment is intended to start in Feb, 2022. Clinical trial information: 202122207. [Table: see text]

Preclinical Characterization and Phase I Trial Results of a Bispecific Antibody Targeting PD-L1 and 4-1BB (GEN1046) in Patients with Advanced Refractory Solid Tumors

Checkpoint inhibitors (CPI) have revolutionized the treatment paradigm for advanced solid tumors; however, there remains an opportunity to improve response rates and outcomes. In preclinical models, 4-1BB costimulation synergizes with CPIs targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis by activating cytotoxic T-cell-mediated antitumor immunity. DuoBody-PD-L1×4-1BB (GEN1046) is an investigational, first-in-class bispecific immunotherapy agent designed to act on both pathways by combining simultaneous and complementary PD-L1 blockade and conditional 4-1BB stimulation in one molecule. GEN1046 induced T-cell proliferation, cytokine production, and antigen-specific T-cell-mediated cytotoxicity superior to clinically approved PD-(L)1 antibodies in human T-cell cultures and exerted potent antitumor activity in transplantable mouse tumor models. In dose escalation of the ongoing first-in-human study in heavily pretreated patients with advanced refractory solid tumors (NCT03917381), GEN1046 demonstrated pharmacodynamic immune effects in peripheral blood consistent with its mechanism of action, manageable safety, and early clinical activity [disease control rate: 65.6% (40/61)], including patients resistant to prior PD-(L)1 immunotherapy.

SIGNIFICANCE

DuoBody-PD-L1×4-1BB (GEN1046) is a first-in-class bispecific immunotherapy with a manageable safety profile and encouraging preclinical and early clinical activity. With its ability to confer clinical benefit in tumors typically less sensitive to CPIs, GEN1046 may fill a clinical gap in CPI-relapsed or refractory disease or as a combination therapy with CPIs. See related commentary by Li et al., p. 1184. This article is highlighted in the In This Issue feature, p. 1171.

First-in-Class Anti-immunoglobulin-like Transcript 4 Myeloid-Specific Antibody MK-4830 Abrogates a PD-1 Resistance Mechanism in Patients with Advanced Solid Tumors

PURPOSE

In this first-in-human study (NCT03564691) in advanced solid tumors, we investigated a novel first-in-class human IgG4 monoclonal antibody targeting the immunoglobulin-like transcript 4 (ILT4) receptor, MK-4830, as monotherapy and in combination with pembrolizumab.

PATIENTS AND METHODS

Patients with histologically/cytologically confirmed advanced solid tumors, measurable disease by RECIST v1.1, and evaluable baseline tumor sample received escalating doses of intravenous MK-4830 every 3 weeks as monotherapy (parts A and B) and in combination with pembrolizumab (part C). Safety and tolerability were the primary objectives. Pharmacokinetics, objective response rate per RECIST v1.1, and molecular biomarkers were also evaluated.

RESULTS

Of 84 patients, 50 received monotherapy and 34 received combination therapy. No dose-limiting toxicities were observed; maximum tolerated dose was not reached. MK-4830 showed dose-related target engagement. Eleven of 34 patients in the dose-escalation phase who received combination therapy achieved objective responses; 5 previously had progressive disease on anti-PD-1/PD-L1 therapies. Exploratory evaluation of the association between response and pretreatment gene expression related to interferon-gamma signaling in tumors suggested higher sensitivity to T-cell inflammation with combination therapy than historically expected with pembrolizumab monotherapy, with greater response at more moderate levels of inflammation.

CONCLUSIONS

This first-in-class MK-4830 antibody dosed as monotherapy and in combination with pembrolizumab was well tolerated with no unexpected toxicities, and demonstrated dose-related evidence of target engagement and antitumor activity. Inflammation intrinsic to the ILT4 mechanism may be facilitated by alleviating the myeloid-suppressive components of the tumor microenvironment, supporting the target of ILT4 as a potential novel immunotherapy in combination with an anti-PD-1/PD-L1 agent.

First-in-human phase 1 study of the anti-TIGIT antibody vibostolimab as monotherapy or with pembrolizumab for advanced solid tumors, including non-small cell lung cancer

BACKGROUND

In this first-in-human phase 1 study, we investigated the safety and efficacy of the anti-TIGIT antibody vibostolimab as monotherapy or in combination with pembrolizumab.

METHODS

Part A enrolled patients with advanced solid tumors and part B enrolled patients with non-small cell lung cancer (NSCLC). Patients received vibostolimab 2.1-700 mg alone or with pembrolizumab 200 mg in part A and vibostolimab 200 mg alone or with pembrolizumab 200 mg in part B. Primary end points were safety and tolerability. Secondary end points included pharmacokinetics and objective response rate (ORR) per RECIST v1.1.

RESULTS

Part A enrolled 76 patients (monotherapy, 34; combination therapy, 42). No dose-limiting toxicities were reported. Across doses, 56% of patients receiving monotherapy and 62% receiving combination therapy had treatment-related adverse events (TRAEs); grade 3-4 TRAEs occurred in 9% and 17% of patients, respectively. The most common TRAEs were fatigue (15%) and pruritus (15%) with monotherapy and pruritus (17%) and rash (14%) with combination therapy. Confirmed ORR was 0% with monotherapy and 7% with combination therapy. In part B, 39 patients had anti-PD-1/PD-L1-naïve NSCLC (all received combination therapy) and 67 had anti-PD-1/PD-L1-refractory NSCLC (monotherapy, 34; combination therapy, 33). In patients with anti-PD-1/PD-L1-naive NSCLC: 85% had TRAEs-the most common were pruritus (38%) and hypoalbuminemia (31%); confirmed ORR was 26%, with responses occurring in both PD-L1-positive and PD-L1-negative tumors. In patients with anti-PD-1/PD-L1‒refractory NSCLC: 56% receiving monotherapy and 70% receiving combination therapy had TRAEs-the most common were rash and fatigue (21% each) with monotherapy and pruritus (36%) and fatigue (24%) with combination therapy; confirmed ORR was 3% with monotherapy and 3% with combination therapy.

CONCLUSION

Vibostolimab plus pembrolizumab was well tolerated and demonstrated antitumor activity in patients with advanced solid tumors, including patients with advanced NSCLC.

Next-generation sequencing in thyroid cancers: do targetable alterations lead to a therapeutic advantage?: A multicenter experience

ABSTRACT

Radioiodine-refractory thyroid cancers (IRTCs) are uncommon and have a poor prognosis. Treatment options for radioiodine-refractory and anaplastic tumors (ATCs) are limited. Although the genomic landscape of thyroid cancer has been studied, there is little evidence on whether next-generation sequencing (NGS) findings translate to tumor control.We analyzed all patients with IRTC and ATC who underwent commercially available NGS in 3 cancer centers.Twenty-two patients were identified, 16 patients with IRTCs and 6 patients with ATCs. Eighteen (82%) had targetable findings in NGS, nine patients were treated accordingly. Median progression-free survival for targeted treatment was 50 months [95% confidence interval (CI95%) 9.8-66.6] and2 months (CI95% 0.2-16.5) for IRTC and ATC, respectively. Of 4 patients who achieved durable responses of 7 to 50 months, 2 are ongoing. The estimated median OS of IRTC receiving targeted treatment was not reached (CI95% 89.7-111.4 months) and was 77.8 months (CI95% 52.5-114.6) for patients treated conventionally (P = .3).NGS may detect clinically significant genetic alterations and benefit patients with advanced thyroid cancers.

LEAP-005: A phase 2 multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the gastric cancer cohort

4030

Background: Lenvatinib, an anti-angiogenic multiple receptor tyrosine kinase inhibitor, in combination with the anti‒PD-1 antibody pembrolizumab, has demonstrated promising antitumor activity with manageable safety in the first- or second-line in a phase 2 trial of patients with advanced gastric cancer. LEAP-005 (NCT03797326) is a phase 2, multicohort, nonrandomized, open-label study evaluating efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here, we present findings from the gastric cancer cohort of LEAP-005. Methods: Eligible patients were aged ≥18 years with histologically or cytologically confirmed metastatic and/or unresectable gastric cancer, received at least 2 prior lines of therapy, had measurable disease per RECIST v1.1, ECOG PS of 0‒1, and provided a tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles of pembrolizumab (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the gastric cancer cohort; 87% were male, 58% were aged < 65 years, and 71% had PD-L1 combined positive score (CPS) ≥1. Median time from first dose to data cutoff (April 10, 2020) was 7.0 months (range, 1.9‒11.9); 19 patients (61%) had discontinued treatment. ORR was 10% (95% CI, 2‒26); 1 patient had CR (3%), and 2 had a PR (6%). 12 patients (39%) had SD. Median DOR was not reached (range, 2.1+ to 2.3+ months). DCR was 48% (95% CI, 30‒67). Median PFS was 2.5 months (95% CI, 1.8‒4.2). Median OS was 5.9 months (95% CI, 2.6‒8.7). 28 patients (90%) had treatment-related AEs, including 13 patients (42%) with grade 3‒5 AEs. 1 patient had a treatment-related AE that led to death (hemorrhage). 8 patients (26%) had immune-mediated AEs: hypothyroidism (n = 5), hyperthyroidism (n = 2), and pneumonitis (n = 1). There were no infusion-related reactions. Conclusions: In patients with advanced gastric cancer who received 2 prior lines of therapy, lenvatinib plus pembrolizumab demonstrated promising antitumor activity and a manageable safety profile. Based on these data, enrollment in the gastric cancer cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

LEAP-005: A phase 2 multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the colorectal cancer cohort

3564

Background: Pembrolizumab (pembro), an anti-PD-1 antibody, is approved for the treatment of patients (pts) with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair (MMR) deficient colorectal cancer, both as first-line treatment and after progression following treatment with fluoropyrimidine, oxaliplatin, and irinotecan. The combination of lenvatinib, a multiple receptor tyrosine kinase inhibitor, and anti-PD-1 treatment showed synergistic antitumor activity in preclinical models. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembro in pts with previously treated advanced solid tumors. We present findings from the colorectal cancer cohort. Methods: In this nonrandomized, open-label, phase 2 study, adult pts (aged ≥18 y) with histologically/cytologically documented metastatic and/or unresectable colorectal cancer, non–MSI-H/pMMR tumor per local determination, previous treatment with oxaliplatin and irinotecan in separate lines of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and a tissue sample evaluable for PD-L1 expression were eligible. Pts received lenvatinib 20 mg QD plus pembro 200 mg Q3W for up to 35 cycles of pembro (̃2 y) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 y in pts with clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 wks, then Q12W to week 102, and Q24W thereafter. Results: 32 pts with colorectal cancer received treatment with lenvatinib plus pembro (median age, 56 y [range, 36-77]; male, 81%; 3L, 91%); median time from first dose to data cutoff (April 10, 2020) was 10.6 mo (range, 5.9-13.1). ORR was 22% (95% CI, 9–40; table). Grade 3–5 treatment-related AEs occurred in 16 (50%) pts. Treatment-related AEs led to treatment discontinuation in 3 pts (grade 2 ischemic stroke [n = 1], grade 3 increased liver transaminases [n = 1], grade 5 intestinal perforation [n = 1]). Conclusions: In pts with previously treated advanced non–MSI-H/pMMR colorectal cancer, lenvatinib plus pembro demonstrated promising antitumor activity and a manageable safety profile. Enrollment in the colorectal cohort was expanded to 100 pts. Clinical trial information: NCT03797326. [Table: see text]

Circulating tumor DNA fraction (ctDNA%) to independently predict for clinical outcomes in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)

5049

Background: CtDNA% (the tumour-derived proportion of cell-free DNA (cfDNA)) is abundant in >60% of mCRPC pts and associates with adverse clinical prognostic factors. However, prognostic associations have not been comprehensively tested across clinical contexts. We evaluated the utility of ctDNA% as an independent prognostic biomarker in patients with mCRPC prior to first-line (1L) therapy. Methods: 410 treatment-naïve mCRPC pts had blood samples drawn prior to 1L therapy and followed prospectively for outcomes. Plasma cfDNA was subjected to deep targeted sequencing and ctDNA% was calculated using validated methods ( Annala, Cancer Discov, 2018 ). Overall survival (OS), PSA progression free survival (PSA PFS) and PSA declines ≥50% from baseline (PSA50 response rate (RR)) were stratified by ctDNA% and compared using Kaplan-Meier and Cox proportional hazards analysis. Results: Median age was 73 yrs. (range 45-98), the majority of pts had ECOG PS 0-1 (78%) and 9.5% had liver metastases at baseline. The most common 1L therapy employed was androgen receptor pathway inhibitors (90%). Median follow-up was 21 mo. (range 1-75) and median ctDNA% was 4.9% (range: 0-89%). Stratifying patients into high ctDNA (>30%) and Low ctDNA (≤2%) groups showed stronger association with OS and PSA PFS than grouping by median (Table). In a univariate comparison to pts with low ctDNA (≤2%), pts with high ctDNA% (>30%) had significantly shorter median PSA PFS, median OS and a lower PSA50 RR (Table). In a multivariable adjustment for clinical prognostic factors and cfDNA concentration, high ctDNA% remained strongly associated with OS (HR= 3.3, 95%CI: 2.1-5.3, p<0.001) and PSA PFS (HR: 3.7, 95%CI: 2.4-5.9, p<0.001). Although ctDNA% and total cfDNA concentration were correlated (R2=0.55), association with OS was stronger for ctDNA% than cfDNA concentration (stratified at median; HR: 2.9 (2.3-3.7), p<0.001 vs HR: 2.1 (1.7-2.6), p<0.001). Conclusions: In a large cohort of treatment-naïve mCRPC pts, ctDNA% prior to 1L treatment provided strong prognostic information independent of known clinical factors. These data further demonstrate the multipronged clinical utility of ctDNA-based profiling for actionable genomic alterations.[Table: see text]

Lenvatinib plus pembrolizumab for patients with previously treated biliary tract cancers in the multicohort phase 2 LEAP-005 study

4080

Background: Second-line treatment options for patients with biliary tract cancers (BTC) are limited. Lenvatinib, an anti-angiogenic multikinase inhibitor, in combination with the programmed death-1 immune checkpoint inhibitor pembrolizumab, has demonstrated promising antitumor activity with a manageable safety profile in patients with select advanced solid tumors. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here we present results from the BTC cohort of LEAP-005. Methods: In this nonrandomized, open-label, phase 2 study, eligible patients were aged ≥18 years with histologically or cytologically documented advanced (metastatic and/or unresectable) BTC with disease progression after 1 prior line of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints were the disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the BTC cohort (ECOG PS 1, 55%; 84% ex-US). As of April 10, 2020, median time from first dose to data cutoff (DCO) was 9.5 months (range, 3.1‒11.9), with 8 patients on treatment at DCO. There were 3 (10%) PRs and 18 (58%) SDs. ORR was 10% (95% CI, 2‒26), and DCR was 68% (95% CI, 49‒83). Median DOR was 5.3 months (range, 2.1+ to 6.2). Median PFS was 6.1 months (95% CI, 2.1‒6.4). Median OS was 8.6 months (95% CI, 5.6 to NR). Treatment-related AEs occurred in 30 patients (97%), including 15 (48%) who had grade 3 AEs; there were no grade 4 or 5 treatment-related AEs. 2 (6%) discontinued treatment due to treatment-related AEs (myocarditis, pyrexia; n = 1 each). The most frequent treatment-related AEs were hypertension (42%), dysphonia (39%), diarrhea (32%), fatigue (32%), and nausea (32%). 14 patients (45%) had immune-mediated AEs and 1 patient (3%) had an infusion-related reaction. Conclusions: Lenvatinib plus pembrolizumab demonstrated encouraging efficacy and manageable toxicity in patients with advanced BTC who had received 1 line of prior therapy. Based on these data, enrollment in the BTC cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

5-hydroxymethylcytosine as a liquid biopsy biomarker in mCRPC

148

Background: 5-hydroxymethylcytosine (5hmC) is an epigenetic modification which regulates gene expression and is associated with active transcription. The optimization of 5hmC sequencing in cell-free DNA (cfDNA) could therefore enable assessment of gene activity through a liquid biopsy. We aimed to investigate the 5hmC landscape of metastatic castration-resistant prostate cancer (mCRPC) and to evaluate the potential of 5hmC modifications in cfDNA as biomarkers of outcome in mCRPC patients. Methods: Genome-wide 5hmC modifications were analyzed with a low-input whole-genome 5hmC sequencing method based on selective chemical labeling in DNA from 93 mCRPC tissue biopsies previously profiled with whole-genome sequencing (WGS), RNA-sequencing and whole-genome bisulfite sequencing (WGBS). In addition, we analyzed 64 cell-free DNA (cfDNA) samples, from men with mCRPC before first-line abiraterone or enzalutamide, with both 5hmC sequencing and a conventional targeted ctDNA panel assessing common genomic alterations. Results: In mCRPC tissue samples, 5hmC enrichment was more strongly associated with gene expression than promoter methylation or copy number. Among cancer hallmark pathways, the androgen response genes had the strongest association between 5hmC and gene expression, suggesting a disease specific marking of gene activation. 5hmC patterns in cfDNA could be used to estimate the circulating tumor DNA fraction (ct-fraction), which was prognostic for overall survival (tertiles of ct-fraction, HR = 1.6 95%CI 1.1-2.3, p = 0.007). Further, 5hmC levels were indicative of gain of oncogene activity (such as AR, MYC, and PIK3CA) and loss of tumor suppressor gene activity (such as RB1, TP53 and BRCA2). The number of alterations, by 5hmC levels, of common drivers of mCRPC was prognostic for overall survival, also after adjusting for ct-fraction (adjusted p = 0.00001), and the prognostic value of common alterations detected by 5hmC sequencing versus conventional targeted ctDNA sequencing was similar. Finally, 5hmC levels in cfDNA of genes not significantly altered by copy number gain or loss (and thus not routinely included in targeted ctDNA sequencing assays), such as TOP2A and EZH2, identified a high-risk subgroup of mCRPC, which was highly prognostic for overall survival independent of ct-fraction (adjusted HR = 1.8 95%CI 1.2-2.8, p = 0.007). Conclusions: 5hmC in mCRPC tissue demonstrated an association with gene expression that was highest for prostate cancer driver genes, highlighting the ability to track disease-specific biology. 5hmC in cfDNA from men with mCRPC can be used to estimate the ct-fraction of the sample, infer activity gain and loss of common drivers of mCRPC, and identify high-risk groups of mCRPC based on alterations not commonly detected with conventional ctDNA sequencing, showing its potential as a liquid biomarker. Further studies are aimed at optimizing and validating 5hmC-based biomarkers in larger cohorts.

Lenvatinib plus pembrolizumab for patients with previously treated biliary tract cancers in the multicohort phase II LEAP-005 study

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Background: Second-line treatment options for patients with biliary tract cancers (BTC) are limited. Lenvatinib, an anti-angiogenic multikinase inhibitor, in combination with the programmed death-1 immune checkpoint inhibitor pembrolizumab, has demonstrated promising antitumor activity with a manageable safety profile in patients with select advanced solid tumors. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here we present results from the BTC cohort of LEAP-005. Methods: In this nonrandomized, open-label, phase II study, eligible patients were aged ≥18 years with histologically or cytologically documented advanced (metastatic and/or unresectable) BTC with disease progression after 1 prior line of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints were the disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the BTC cohort (ECOG PS 1, 55%; 84% ex-US). As of April 10, 2020, median time from first dose to data cutoff (DCO) was 9.5 months (range, 3.1‒11.9), with 16 patients on treatment at DCO. There were 3 (10%) PRs and 18 (58%) SDs. ORR was 10% (95% CI, 2‒26), and DCR was 68% (95% CI, 49‒83). Median DOR was 5.3 months (range, 2.1+ to 6.2). Median PFS was 6.1 months (95% CI, 2.1‒6.4). Median OS was 8.6 months (95% CI, 5.6 to NR). Treatment-related AEs occurred in 30 patients (97%), including 15 (48%) who had grade 3‒4 AEs; there were no treatment-related deaths. 2 (6%) discontinued treatment due to treatment-related AEs (myocarditis, pyrexia; n = 1 each). The most frequent treatment-related AEs were hypertension (42%), dysphonia (39%), diarrhea (32%), fatigue (32%), and nausea (32%). 14 patients (45%) had immune-mediated AEs and 1 patient (3%) had an infusion-related reaction. Conclusions: Lenvatinib plus pembrolizumab demonstrated encouraging efficacy and manageable toxicity in patients with advanced BTC who had received 1 line of prior therapy. Based on these data, enrollment in the BTC cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

LEAP-005: A phase II multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the gastric cancer cohort

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Background: Lenvatinib, an anti-angiogenic multiple receptor tyrosine kinase inhibitor, in combination with the anti‒PD-1 antibody pembrolizumab, has demonstrated promising antitumor activity with manageable safety in the first- or second-line in a phase 2 trial of patients with advanced gastric cancer. LEAP-005 (NCT03797326) is a phase 2, multicohort, nonrandomized, open-label study evaluating efficacy and safety of lenvatinib plus pembrolizumab in patients with previously treated advanced solid tumors; here, we present findings from the gastric cancer cohort of LEAP-005. Methods: Eligible patients were aged ≥18 years with histologically or cytologically confirmed metastatic and/or unresectable gastric cancer, received at least 2 prior lines of therapy, had measurable disease per RECIST v1.1, ECOG PS of 0‒1, and provided a tissue sample evaluable for PD-L1 expression. Patients received lenvatinib 20 mg once daily plus pembrolizumab 200 mg Q3W for up to 35 cycles of pembrolizumab (approximately 2 years) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 years in patients experiencing clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR; comprising CR, PR, and SD), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 weeks, then Q12W to week 102, and Q24W thereafter. Results: 31 patients were enrolled in the gastric cancer cohort; 87% were male, 58% were aged < 65 years, and 71% had PD-L1 combined positive score (CPS) ≥1. Median time from first dose to data cutoff (April 10, 2020) was 7.0 months (range, 1.9‒11.9); 19 patients (61%) had discontinued treatment. ORR was 10% (95% CI, 2‒26); 1 patient had CR (3%), and 2 had a PR (6%). 12 patients (39%) had SD. Median DOR was not reached (range, 2.1+ to 2.3+ months). DCR was 48% (95% CI, 30‒67). Median PFS was 2.5 months (95% CI, 1.8‒4.2). Median OS was 5.9 months (95% CI, 2.6‒8.7). 28 patients (90%) had treatment-related AEs, including 13 patients (42%) with grade 3‒5 AEs. 1 patient had a treatment-related AE that led to death (hemorrhage). 8 patients (26%) had immune-mediated AEs: hypothyroidism (n = 5), hyperthyroidism (n = 2), and pneumonitis (n = 1). There were no infusion-related reactions. Conclusions: In patients with advanced gastric cancer who received 2 prior lines of therapy, lenvatinib plus pembrolizumab demonstrated promising antitumor activity and a manageable safety profile. Based on these data, enrollment in the gastric cancer cohort has been expanded to 100 patients. Clinical trial information: NCT03797326.

LEAP-005: A phase II multicohort study of lenvatinib plus pembrolizumab in patients with previously treated selected solid tumors—Results from the colorectal cancer cohort

94

Background: Pembrolizumab (pembro), an anti-PD-1 antibody, is approved for the treatment of patients (pts) with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair (MMR) deficient colorectal cancer, both as first-line treatment and after progression following treatment with fluoropyrimidine, oxaliplatin, and irinotecan. The combination of lenvatinib, a multiple receptor tyrosine kinase inhibitor, and anti-PD-1 treatment showed synergistic antitumor activity in preclinical models. LEAP-005 (NCT03797326) is evaluating the efficacy and safety of lenvatinib plus pembro in pts with previously treated advanced solid tumors. We present findings from the colorectal cancer cohort. Methods: In this nonrandomized, open-label, phase 2 study, adult pts (aged ≥18 y) with histologically/cytologically documented metastatic and/or unresectable colorectal cancer, non–MSI-H/pMMR tumor per local determination, previous treatment with oxaliplatin and irinotecan in separate lines of therapy, measurable disease per RECIST v1.1, ECOG PS of 0‒1, and a tissue sample evaluable for PD-L1 expression were eligible. Pts received lenvatinib 20 mg QD plus pembro 200 mg Q3W for up to 35 cycles of pembro (~2 y) or until confirmed disease progression, unacceptable toxicity, or withdrawal of consent. Treatment with lenvatinib could continue beyond 2 y in pts with clinical benefit. Primary endpoints were ORR (per RECIST v1.1 by blinded independent central review) and safety. Secondary endpoints included disease control rate (DCR), duration of response (DOR), PFS, and OS. Tumor imaging was performed Q9W from treatment initiation for 54 wks, then Q12W to week 102, and Q24W thereafter. Results: 32 pts with colorectal cancer received treatment with lenvatinib plus pembro (median age, 56 y [range, 36-77]; male, 81%; 3L, 91%); median time from first dose to data cutoff (April 10, 2020) was 10.6 mos (range, 5.9-13.1) ORR was 22% (95% CI, 9-40; Table). Grade 3-5 treatment-related AEs occurred in 16 (50%) pts. Treatment-related AEs led to treatment discontinuation in 3 pts (grade 2 ischemic stroke [n = 1], grade 3 increased liver transaminases [n = 1], grade 5 intestinal perforation [n = 1]). Efficacy Results. Clinical trial information: NCT03797326. NR, not reached aConfirmation was not required for best overall response of SD, but a final visit response of SD or better must have occurred ≥6 wks after starting study treatment Conclusions: In pts with previously treated advanced non–MSI-H/pMMR colorectal cancer, lenvatinib plus pembro demonstrated promising antitumor activity and a manageable safety profile. Enrollment in the colorectal cohort was expanded to 100 pts. [Table: see text]

Abstract CT134: Tilsotolimod engages the TLR9 pathway to promote antigen presentation and Type-I IFN signaling in solid tumors

Background: Tilsotolimod, an investigational Toll-like receptor 9 (TLR9) agonist, modulates the tumor immune microenvironment and has single-agent antitumor activity in preclinical models. The ILLUMINATE-101 phase 1b study (NCT03052205) explored the safety, efficacy, and immune effects of intratumoral tilsotolimod in multiple solid tumors.

Methods: Adults with a histologically- or cytologically-confirmed diagnosis of cancer not amenable to curative therapies received intratumoral tilsotolimod 8, 16, 23, or 32 mg into a single lesion on Days 1, 8, and 15 of Cycle 1 and Day 1 of each subsequent 3-week cycle, for up to 17 cycles. Additionally, patients with advanced melanoma were enrolled into an expansion cohort at the recommended phase 2 dose of 8 mg. The primary objective was to characterize safety (dose escalation cohort) and efficacy (expansion cohort). Secondary objectives included pharmacokinetics of tilsotolimod. Immunological assessment of injected and non-injected tumors was an exploratory objective. Blood samples and tumor biopsies of injected lesions were obtained at baseline and 24 hours post treatment for immune analyses.

Results: A total of 54 patients were enrolled. Of the 38 patients in the dose escalation cohort, 35 had metastatic disease. Patients in this cohort had a median of 7 prior lines of treatment, and the most common cancer types were pancreatic (12 patients) and colorectal (7 patients). All 16 patients in the melanoma cohort had metastatic disease with a median of 3 lines of prior therapy, and 10 patients had elevated LDH. Injected lesions were deep and required interventional radiology in 52 of 54 patients. No dose-limiting toxicities were observed. The most common treatment-related adverse events were pyrexia, fatigue, chills, nausea, and vomiting. Compared to pretreatment, biopsies of injected tumors at 24 hours showed increased activation of the Type-I IFN pathway, upregulation of MHC class I/II, IFNγ expression, and expression of multiple immune checkpoints (i.e. PD-1, LAG3). Of the 35 evaluable patients in the dose escalation cohort, 12 (34%) achieved a best overall response of stable disease (SD). Of the 16 evaluable patients in the melanoma cohort, 3 had SD, 1 who had a 35% tumor reduction with no confirmatory scan.

Conclusions: Tilsotolimod was generally well tolerated and induced alterations in the tumor microenvironment, including immune checkpoint upregulation, activation of dendritic cells, and induction of Type-I IFN signaling. Additional clinical studies of tilsotolimod in combination with checkpoint inhibitors are underway (NCT03445533, NCT03865082, and NCT02644967).

Citation Format: Hani M. Babiker, Vivek Subbiah, Asim Ali, Alain Algazi, Jacob Schachter, Michal Lotem, Corinne Maurice-Dror, Daniel Hendler, Shah Rahimian, Hans Minderman, Cara Haymaker, Chantale Bernatchez, Ravi Murthy, Rolf Hultsch, Nadia Caplan, Gregory Woodhead, Charles Hennemeyer, Sri Chunduru, Peter Anderson, Adi Diab, Erkut Borazanci, Igor Puzanov. Tilsotolimod engages the TLR9 pathway to promote antigen presentation and Type-I IFN signaling in solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT134.

A phase Ib, open-label, dose-escalation trial of naptumomab estafenatox (Nap) in combination with durvalumab (MEDI4736) in subjects with selected advanced or metastatic solid tumors

TPS3160

Background: Immunotherapy with the anti-PD-(L)1 checkpoint inhibitors (CPIs) has been largely ineffective in so-called non-immunogenic “cold tumors”. Facilitating T cell infiltration is necessary to invoke an immune response which may be augmented or complemented by the activity of CPIs like durvalumab. Selective T cell Redirection Proteins (STRs) are fusion proteins that consist of genetically engineered Superantigen (Sag) linked to Fragment antigen binding (Fab) moieties directed to tumor-associated antigens. Nap is a first in class STR compound, recognizing the tumor-associated oncofetal antigen 5T4, whereas the SAg moiety selectively engages the T cell receptor β variable (TRBV) 7-9. Nap has been shown to induce specific T cells expansion, activation and infiltration into the tumor in pre-clinical and clinical studies. Pre-clinical data demonstrated that the combination of STR with CPI may lead to long term durable responses not possible in most patients receiving single agent CPI therapy and suggests that combining CPIs with STR may be a promising therapeutic strategy for patients with solid tumors. Methods: Patients will be treated with the combination of Nap and durvalumab using a flat dose of durvalumab (1120 mg) and the 3+3 design for Nap dose escalation (2, 5, 10, 15 and 20 mcg/kg). The MTD of Nap for the combination treatment will be established based on DLTs occurring during the first treatment cycle. The dose escalation part will be followed by MTD expansion cohort in which 10–15 patients will be treated with MTD of Nap and 1120 mg durvalumab (Clinical trial registry number NCT03983954). Major eligibility criteria include patients with pretreated advanced or metastatic, 5T4 expressing solid tumors, including patients previously progressed on CPI therapy. As of January 2020, enrollment to dose levels 2, 5 and 10 mcg/kg has been completed without DLT, enrollment to dose level 15 mcg/kg will start on February 2020. Clinical trial information: NCT03983954 .

A phase I study of mRNA-2752, a lipid nanoparticle encapsulating mRNAs encoding human OX40L, IL-23, and IL-36γ, for intratumoral (iTu) injection alone and in combination with durvalumab

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Background: mRNA-2752 is a novel mRNA-based therapeutic agent encoding OX40L T cell co-stimulator, IL-23 and IL-36γ pro-inflammatory cytokines. Here we present findings from a first-in-human study of iTu mRNA-2752 in solid tumor patients as monotherapy or in combination with durvalumab (durva). At the time of presentation, data will encompass the monotherapy escalation MTD/RDE along with the supporting translational work, and the available data in combination. Methods: iTu mRNA-2752 was administered every 2 weeks for up to 7 doses as monotherapy or in combination with durva in patients with advanced solid malignancy or lymphoma. Biomarker analyses include measurement of IL-23, IL-36γ and pro-inflammatory cytokine proteins in pre- and post-treatment tumor biopsies and plasma. PD-L1 immunohistochemistry was used to further characterize baseline status and changes to the TME with treatment. Results: As of 20 December 2019, 23 solid tumor patients have been treated either with mRNA-2752 alone (n = 14) or in combination (n = 9) and has been well tolerated with no dose limiting toxicities or related grade 3/4 toxicities. Of the 17 patients evaluated per RECIST and iRECIST, 1 had a PR (iRECIST), 6 had SD, and 10 had PD. The patient with a PR (52% tumor reduction) received 0.5 mg mRNA-2752 with durva, and had aPD-1/L1 naïve squamous-cell bladder carcinoma. Tumor shrinkage was observed in an additional 5 patients in injected and/or uninjected lesions in both monotherapy and combination. Preliminary biomarker data showed increased IL-23 and IL-36γ protein expression after 6-24 hours, and increased levels of downstream cytokines IL-22 and IL-6, respectively. Pro-inflammatory cytokines (e.g. IFN-γ, TNF-α) were also significantly increased at 1 day and 1-week post-treatment. Significant increases in PD-L1 expression predominantly in tumor-associated immune cells were observed after first dose and persisted up to 29 days after treatment. Conclusions: iTu mRNA-2752 given as monotherapy and in combination with durva is tolerable at all dose levels studied, and administration can be associated with tumor shrinkage. Analyses of tumor and plasma biomarkers suggest a sustained immunomodulatory effect of treatment that includes elevated IFN-γ, TNF-α, and PD-L1 levels. These data support the ongoing testing of the mRNA-2752/durva combination in the dose escalation part of the study. Clinical trial information: NCT03739931 .

Next-generation sequencing in salivary gland carcinoma: Targetable alterations lead to a therapeutic advantage-Multicenter experience

BACKGROUND

Salivary gland cancers (SGCs) are rare. The approach to metastatic patients is histology-dependent. There is little evidence on whether next-generation sequencing (NGS) findings translate to tumor control in SGCs.

METHODS

We analyzed all patients with histologically confirmed SGC who underwent NGS.

RESULTS

Twenty-seven patients were identified, 14 (51.8%) had targetable findings in NGS: 5 ERBB2 amplifications, 3 PIK3CA mutations, 2 RUNX1 mutations, 1 TRIM33-RET fusion, 1 FGFR3-TACC3 fusion, 1 microsatellite instability-high, and 2 high mutational burden. Ten patients were treated accordingly. Median progression-free survival for targeted treatment was 8.4 months. Of five patients who achieved durable responses of 8.4 to 31.3 months, two are ongoing. The overall median survival was not reached for patients receiving targeted treatment and was 40.4 months for patients treated conventionally (P = .18).

CONCLUSIONS

In the absence of a well-established therapeutic approach, NGS may detect clinically significant genetic alterations and benefit patients with advanced SGC.

Genomic analysis of urothelial cancer and associations with treatment choice and outcome

e16026

Background: The use of next generation sequencing (NGS) is in a constant rise, without clear evidence to its utility in guiding treatment choices in urologic malignancies. While platinum-based chemotherapy (chemo) is still the mainstay of treatment, anti-PD1/L1 antibodies (IO) and FGFR3 inhibitors are emerging therapeutic options. Here our aim was to retrospectively assess the utility of next-generation sequencing (NGS) in selecting advanced treatment lines and define the response rates (RR) to chemo and IO in a real-life cohort. Methods: Metastatic urothelial carcinoma (UC) patients (pts) receiving first-line chemo were included. Paraffin-embedded pathological samples were subjected to FoundationOne genomic analysis (Roche) and to PD-L1 IHC staining using the FDA-approved Ventana's companion diagnostic test. Reports were anonymized and analysis was performed using Excel (Microsoft Office). Response was defined as either a clinically or radiologically-significant improvement. Results: 60 pts were included in this analysis with a median age of 69, of which 87.7% were men and 70% were current or past-smokers. RR to first line chemo or IO was 66% (95% CI 50-82) and 33% (95% CI 12-64), respectively. RR to second-line IO was 14% ((95% CI 4-40). Median TMB was 10 Mut/Mb (range 1-62) with no difference between smokers and non-smokers. 31% pts had tumor PD-L1 staining of > 5% and 3.7% were MSI-high. 107 genes were altered across all pts. The median number of genomic alterations (mutations (muts), amplifications (amps), deletions (dels) and re-arrangements) was 7 (range 2-17). The most frequent were TERT promotor and TP53 mutations, occurring in in 39 (69.6%) and 30 (53.6%) pts, respectively. FGFR3 alterations were found in 9 (15%) pts (7 mut and 2 fusions), 12 pts (20%) had alterations in ERBB2/Her2 (6 amps, 3 muts, 3 equivocal amps), BRCA1 mutations were found in 6 (10%) pts, and TSC1 alterations were found in 6 (10%) pts (4 muts and 2 dels). Altogether, about 40% of patients had potentially actionable alterations; of these, to date, the treatment of 8 patients (13%) was consequently altered. The RR to IO was non-significantly higher in pts with TMB > 10 (29% VS 20%, p = 0.1) across all pts in this cohort. Conclusions: RR to first-line chemo is higher than to first-line IO, and the association between TMB and response to IO is still debatable in UC. NGS can yield potentially 'actionable' alterations in about 40% of UC pts, and can change the treatment paradigm in the third of them.

Glucocorticoids as an adjunct to oncologic treatment in solid malignancies - Not an innocent bystander

Glucocorticoids are steroidal hormones which exert their action via genomic and non-genomic mechanisms. In the clinical setting, glucocorticoids are utilized for their anti-inflammatory, anti-allergenic and immunomodulatory effects and for their well-established, pro-apoptotic effects on hematological malignancies. In the treatment of solid tumors, glucocorticoids serve primarily for alleviation of tumor- and treatment-related symptoms and in most cases are not considered to have a direct effect on tumor growth and spread. However, significant pre-clinical data suggest that glucocorticoids have diverse effects on tumor progression, both pro- and anti- tumorigenic. In contrast, the clinical data regarding the pro- and anti-tumorigenic effects of glucocorticoids on solid tumors is scarce, and summarized in this review. The following review presents the suggested glucocorticoids mechanism of action and the effects of glucocorticoids on tumor cells, on the tumor microenvironment and on tumor response to cytotoxic therapy, in the pre-clinical and clinical settings.