Efficacy, safety, and biomarker analyses of bintrafusp alfa, a bifunctional fusion protein targeting TGF-ß and PD-L1, in patients with advanced non-small cell lung cancer.

BACKGROUND: Bintrafusp alfa, a first-in-class bifunctional fusion protein targeting transforming growth factor-ß (TGF-ß) and programmed cell death ligand 1, has demonstrated encouraging efficacy as second-line treatment in patients with non-small cell lung cancer (NSCLC) in a dose expansion cohort of the phase 1, open-label clinical trial (NCT02517398). Here, we report the safety, efficacy, and biomarker analysis of bintrafusp alfa in a second expansion cohort of the same trial (biomarker cohort). METHODS: Patients with stage IIIb/IV NSCLC who were either immune checkpoint inhibitor (ICI)-naïve (n=18) or ICI-experienced (n=23) were enrolled. The primary endpoint was the best overall response. Paired biopsies (n=9/41) and peripheral blood (n=14/41) pretreatment and on-treatment were studied to determine the immunological effects of treatment and for associations with clinical activity. RESULTS: Per independent review committee assessment, objective responses were observed in the ICI-naïve group (overall response rate, 27.8%). No new or unexpected safety signals were identified. Circulating TGF-ß levels were reduced (>97%; p<0.001) 2 weeks after initiation of treatment with bintrafusp alfa and remained reduced up to 12 weeks. Increases in lymphocytes and tumor-associated macrophages (TAMs) were observed in on-treatment biospies, with an increase in the M2 (tumor trophic TAMs)/M1 (inflammatory TAMs) ratio associated with poor outcomes. Specific peripheral immune analytes at baseline and early changes after treatment were associated with clinical response. CONCLUSIONS: Bintrafusp alfa was observed to have modest clinical activity and manageable safety, and was associated with notable immunologic changes involving modulation of the tumor immune microenvironment in patients with advanced NSCLC.

Tumor growth inhibition modeling in patients with second line biliary tract cancer and first line non-small cell lung cancer based on bintrafusp alfa trials.

This analysis aimed to quantify tumor dynamics in patients receiving either bintrafusp alfa (BA) or pembrolizumab, by population pharmacokinetic (PK)-pharmacodynamic modeling, and investigate clinical and molecular covariates describing the variability in tumor dynamics by pharmacometric and machine-learning (ML) approaches. Data originated from two clinical trials in patients with biliary tract cancer (BTC; NCT03833661) receiving BA and non-small cell lung cancer (NSCLC; NCT03631706) receiving BA or pembrolizumab. Individual drug exposure was estimated from previously developed population PK models. Population tumor dynamics models were developed for each drug-indication combination, and covariate evaluations performed using nonlinear mixed-effects modeling (NLME) and ML (elastic net and random forest models) approaches. The three tumor dynamics' model structures all included linear tumor growth components and exponential tumor shrinkage. The final BTC model included the effect of drug exposure (area under the curve) and several covariates (demographics, disease-related, and genetic mutations). Drug exposure was not significant in either of the NSCLC models, which included two, disease-related, covariates in the BA arm, and none in the pembrolizumab arm. The covariates identified by univariable NLME and ML highly overlapped in BTC but showed less agreement in NSCLC analyses. Hyperprogression could be identified by higher tumor growth and lower tumor kill rates and could not be related to BA exposure. Tumor size over time was quantitatively characterized in two tumor types and under two treatments. Factors potentially related to tumor dynamics were assessed using NLME and ML approaches; however, their net impact on tumor size was considered as not clinically relevant.

Bintrafusp Alfa Versus Pembrolizumab in Patients With Treatment-Naive, Programmed Death-Ligand 1-High Advanced NSCLC: A Randomized, Open-Label, Phase 3 Trial.

INTRODUCTION: Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-ßRII (a TGF-ß "trap") fused to a human immunoglobulin G1 monoclonal antibody blocking programmed death-ligand 1 (PD-L1), has exhibited clinical activity in a phase 1 expansion cohort of patients with PD-L1-high advanced NSCLC. METHODS: This adaptive phase 3 trial (NCT03631706) compared the efficacy and safety of bintrafusp alfa versus pembrolizumab as first-line treatment in patients with PD-L1-high advanced NSCLC. Primary end points were progression-free survival according to Response Evaluation Criteria in Solid Tumors version 1.1 per independent review committee and overall survival. RESULTS: Patients (N = 304) were randomized one-to-one to receive either bintrafusp alfa or pembrolizumab (n = 152 each). The median follow-up was 14.3 months (95% confidence interval [CI]: 13.1-16.0 mo) for bintrafusp alfa and 14.5 months (95% CI: 13.1-15.9 mo) for pembrolizumab. Progression-free survival by independent review committee was not significantly different between bintrafusp alfa and pembrolizumab arms (median = 7.0 mo [95% CI: 4.2 mo-not reached (NR)] versus 11.1 mo [95% CI: 8.1 mo-NR]; hazard ratio = 1.232 [95% CI: 0.885-1.714]). The median overall survival was 21.1 months (95% CI: 21.1 mo-NR) for bintrafusp alfa and 22.1 months (95% CI: 20.4 mo-NR) for pembrolizumab (hazard ratio = 1.201 [95% CI: 0.796-1.811]). Treatment-related adverse events were higher with bintrafusp alfa versus pembrolizumab; grade 3-4 treatment-related adverse events occurred in 42.4% versus 13.2% of patients, respectively. The study was discontinued at an interim analysis as it was unlikely to meet the primary end point. CONCLUSIONS: First-line treatment with bintrafusp alfa did not exhibit superior efficacy compared with pembrolizumab in patients with PD-L1-high, advanced NSCLC.

Phase 2 trial of bintrafusp alfa as second-line therapy for patients with locally advanced/metastatic biliary tract cancers.

BACKGROUND AND AIMS: Biliary tract cancers are rare, heterogeneous cancers with poor prognoses. Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-ßRII (a TGF-ß "trap") fused to a human IgG1 monoclonal antibody blocking programmed death ligand 1, was evaluated in patients with locally advanced/metastatic chemorefractory biliary tract cancers. APPROACH AND RESULTS: This multicenter, single-arm, open-label, phase 2 study (NCT03833661) enrolled adults with locally advanced or metastatic biliary tract cancer that was intolerant to or had failed first-line systemic platinum-based chemotherapy. Patients received 1200 mg bintrafusp alfa intravenously Q2W. The primary endpoint was confirmed objective response according to Response Evaluation Criteria in Solid Tumors 1.1 assessed by IRC. Secondary endpoints included duration of response, durable response rate, safety, progression-free survival, and overall survival.Between March 2019 and January 2020, 159 patients were enrolled. Median follow-up was 16.1 (range, 0.0-19.3) months; 17 patients (10.7%; 95% CI: 6.4%-16.6%) achieved an objective response. Median duration of response was 10.0 (range, 1.9-15.7) months; 10 patients (6.3%; 95% CI: 3.1%-11.3%) had a durable response (≥6 mo). Median progression-free survival was 1.8 months (95% CI: 1.7-1.8 mo); median overall survival was 7.6 months (95% CI: 5.8-9.7 mo). Overall survival rates were 57.9% (6 mo) and 38.8% (12 mo). Grade ≥3 adverse events occurred in 26.4% of patients, including one treatment-related death (hepatic failure). Frequent grade ≥3 adverse events included anemia (3.8%), pruritus (1.9%), and increased alanine aminotransferase (1.9%). CONCLUSIONS: Although this study did not meet its prespecified primary endpoint, bintrafusp alfa demonstrated clinical activity as second-line treatment in this hard-to-treat cancer, with durable responses and a manageable safety profile.

Bintrafusp Alfa: A Bifunctional Fusion Protein Targeting PD-L1 and TGF-ß, in Patients with Pretreated Colorectal Cancer: Results from a Phase I Trial.

Colorectal cancer (CRC) is a heterogeneous and complex disease with limited treatment options. Targeting transforming growth factor ß (TGF-ß) and programmed death ligand 1 pathways may enhance antitumor efficacy. Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-ß receptor II (a TGF-ß "trap") fused to a human IgG1 monoclonal antibody blocking programmed cell death ligand 1. We report results from an expansion cohort of a phase I study (NCT02517398) in patients with heavily pretreated advanced CRC treated with bintrafusp alfa. As of May 15, 2020, 32 patients with advanced CRC had received bintrafusp alfa for a median duration of 7.1 weeks. The objective response rate was 3.1% and the disease control rate was 6.3% (1 partial response, 1 stable disease); 2 patients were not evaluable. The safety profile was consistent with previously reported data.

Identification of Clinical Candidate M2698, a Dual p70S6K and Akt Inhibitor, for Treatment of PAM Pathway-Altered Cancers.

Herein, we report the discovery of a novel class of quinazoline carboxamides as dual p70S6k/Akt inhibitors for the treatment of tumors driven by alterations to the PI3K/Akt/mTOR (PAM) pathway. Through the screening of in-house proprietary kinase library, 4-benzylamino-quinazoline-8-carboxylic acid amide 1 stood out, with sub-micromolar p70S6k biochemical activity, as the starting point for a structurally enabled p70S6K/Akt dual inhibitor program that led to the discovery of M2698, a dual p70S6k/Akt inhibitor. M2698 is kinase selective, possesses favorable physical, chemical, and DMPK profiles, is orally available and well tolerated, and displayed tumor control in multiple in vivo studies of PAM pathway-driven tumors.

Discovery of 4-aminopyrimidine analogs as highly potent dual P70S6K/Akt inhibitors.

Activation of the PI3K/Akt/mTOR kinase pathway is associated with human cancers. A dual p70S6K/Akt inhibitor is sufficient to inhibit strong tumor growth and to block negative impact of the compensatory Akt feedback loop activation. A scaffold docking strategy based on an existing quinazoline carboxamide series identified 4-aminopyrimidine analog 6, which showed a single-digit nanomolar and a micromolar potencies in p70S6K and Akt enzymatic assays. SAR optimization improved Akt enzymatic and p70S6K cellular potencies, reduced hERG liability, and ultimately discovered the promising candidate 37, which exhibited with a single digit nanomolar value in both p70S6K and Akt biochemical assays, and hERG activities (IC50 = 17.4 µM). This agent demonstrated dose-dependent efficacy in inhibiting mice breast cancer tumor growth and covered more than 90% pS6 inhibition up to 24 h at a dose of 200 mg/kg po.

Discovery of Small-Molecule Selective mTORC1 Inhibitors via Direct Inhibition of Glucose Transporters.

The mechanistic target of rapamycin (mTOR) is a central regulator of cellular metabolic processes. Dysregulation of this kinase complex can result in a variety of human diseases. Rapamycin and its analogs target mTORC1 directly; however, chronic treatment in certain cell types and in vivo results in the inhibition of both mTORC1 and mTORC2. We have developed a high-throughput cell-based screen for the detection of phosphorylated forms of the mTORC1 (4E-BP1, S6K1) and mTORC2 (Akt) substrates and have identified and characterized a chemical scaffold that demonstrates a profile consistent with the selective inhibition of mTORC1. Stable isotope labeling of amino acids in cell culture-based proteomic target identification revealed that class I glucose transporters were the primary target for these compounds yielding potent inhibition of glucose uptake and, as a result, selective inhibition of mTORC1. The link between the glucose uptake and selective mTORC1 inhibition are discussed in the context of a yet-to-be discovered glucose sensor.

M2698 is a potent dual-inhibitor of p70S6K and Akt that affects tumor growth in mouse models of cancer and crosses the blood-brain barrier.

Dysregulated PI3K/Akt/mTOR (PAM) pathway signaling occurs in ~30% of human cancers, making it a rational target for new therapies; however, the effectiveness of some PAM pathway inhibitors, such as mTORC rapalogs, may be compromised by a compensatory feedback loop leading to Akt activation. In this study, the p70S6K/Akt dual inhibitor, M2698 (previously MSC2363318A), was characterized as a potential anti-cancer agent through examination of its pharmacokinetic, pharmacodynamic and metabolic properties, and anti-tumor activity. M2698 was highly potent in vitro (IC50 1 nM for p70S6K, Akt1 and Akt3 inhibition; IC50 17 nM for pGSK3ß indirect inhibition) and in vivo (IC50 15 nM for pS6 indirect inhibition), and relatively selective (only 6/264 kinases had an IC50 within 10-fold of p70S6K). Orally administered M2698 crossed the blood-brain barrier in rats and mice, with brain tumor exposure 4-fold higher than non-disease brain. Dose-dependent inhibition of target substrate phosphorylation was observed in vitro and in vivo, indicating that M2698 blocked p70S6K to provide potent PAM pathway inhibition while simultaneously targeting Akt to overcome the compensatory feedback loop. M2698 demonstrated dose-dependent tumor growth inhibition in mouse xenograft models derived from PAM pathway-dysregulated human triple-negative (MDA-MB-468) and Her2-expressing breast cancer cell lines (MDA-MB-453 and JIMT-1), and reduced brain tumor burden and prolonged survival in mice with orthotopically implanted U251 glioblastoma. These findings highlight M2698 as a promising PAM pathway inhibitor whose unique mechanism of action and capacity to pass the blood-brain barrier warrant clinical investigation in cancers with PAM pathway dysregulation, and those with central nervous system involvement.

Improving DNA array data quality by minimising 'neighbourhood' effects.

Gene expression studies using cDNA arrays require robust and sensitive detection methods. Being extremely sensitive, radioactive detection suffers from the influence of signals positioned in each other's vicinity, the 'neighbourhood' effect. This limits the gene density of arrays and the quality of the results obtained. We have investigated the quantitative influence of different parameters on the 'neighbourhood' effect. By using a model experimental system, we could show that the effect is linear and depends only on the intensity of the hybridisation signal. We identified a common factor that can describe the influence of the neighbour spots based on their intensities. This factor is <1%, but it has to be taken into account if a high dynamic range of gene expression is to be detected. We could also derive the factor, although with less precision, from comparison of duplicate spots on arrays of 4565 different clones and replication of the hybridisation experiments. The calculated coefficient applied to our actual experimental results not only revealed previously undetected tissue or cell-specific expression differences, but also increased the dynamic range of detection. It thus provides a relatively simple way of improving DNA array data quality with few experimental modifications.