VEGF Pathway Inhibitors Research Articles

Stigmast-4-en-3-one from Euonymus alatus (Thunb.) Siebold. improves diabetic retinopathy and angiogenesis mediated by glucocorticoids receptor

Ethnopharmacological relevanceEuonymus alatus (Thunb.) Siebold. (EA), a traditional Chinese medicine, is widely used in the treatment of diabetes. Our group has previously found that EA could treat diabetic retinopathy (DR) and stigmast-4-en-3-one (Numbered E6) is the active substance responsible for inhibiting angiogenesis in vitro by EA. However, the effects and mechanisms of E6 in the treatment of DR is still unknown. Aim of the studyThe aim of this study was to investigate the effects and mechanisms of E6 in EA on DR. Additionally, a comparison was made between the effects of E6 and triamcinolone acetonide (TA), as well as the side effects of E6 and dexamethasone. Materials and methodsOcular affinity assessment and pharmacokinetic parameter prediction were conducted to evaluate the potential of E6 to treat DR. Retinal endothelial cells were used to investigate the in vitro inhibitory effect of E6 on vascular proliferation. Additionally, chicken embryos, zebrafish, and mice were used to investigate the in vivo anti-vascular proliferation effect of E6. Finally, diabetic mice were used to investigate whether E6 improves diabetic retinopathy and to compare its efficacy with that of TA. We then used network pharmacology to study the targets of E6 and performed molecular docking; followed by immunofluorescence experiments, ELISA, Western blot, and tube formation experiments to further investigate its mechanism. Finally, we compared the side effects of E6 with those of dexamethasone. ResultsE6 was found to have an affinity for the eye and to inhibit vascular proliferation both in vivo and in vitro. Moreover, E6 was found to be more efficacious than TA in the treatment of DR. Molecular docking experiments predicted that the glucocorticoid receptor (GR) is a potential target of E6, and immunofluorescence analyses confirmed that E6 upregulated the expression of the GR in the retina of hyperglycemic mice. In addition, western blotting results and tube formation experiments showed that E6 also attenuated angiogenesis by inhibiting the Hippo and VEGF pathways. Finally, by comparing the effects of E6 and dexamethasone on glucose regulation and osteoporosis, E6 was found to have fewer side effects. ConclusionsE6 is a highly effective drug for the treatment of DR, superior to TA and with fewer side effects than dexamethasone. Its mechanism involves the activation of glucocorticoid receptor and inhibition of Hippo and VEGF pathways to alleviate angiogenesis and inflammation. This study is the first to investigate the role and mechanism of E6 in improving DR. The findings suggest that E6 has unique advantages in the treatment of DR.

Ileal perforation at the site of peritoneal metastasis with intestinal infiltration by dual EGFR-VEGF pathway inhibition in an EGFR-mutant non-small cell lung cancer patient.

Gastrointestinal (GI) perforation including ileal perforation is a rare complication of antivascular endothelial growth factor (anti-VEGF) therapy. Risk factors of GI perforation have not been fully understood. This report highlights the case of a patient who experienced GI perforation at the site of peritoneal metastasis with intestinal infiltration immediately after treatment with dual epidermal growth factor receptor (EGFR)-VEGF pathway inhibition agents for EGFR-mutant non-small cell lung cancer (NSCLC). The administration of dual EGFR-VEGF pathway inhibition agents in EGFR mutant NSCLC patients appears to elevate the risk of GI perforation. This report provides insights into the association between EGFR mutant NSCLC and the susceptibility to GI perforation following treatment with dual EGFR-VEGF pathway inhibition agents.

VEGF and EGFR signaling pathways are involved in the baicalein attenuation of OVA-induced airway inflammation and airway remodeling in mice

BackgroundAlthough Traditional Chinese Medicine (TCM) has been used for treating asthma for centuries, the understanding of its mechanism of action is still limited. Thus, the purpose of this study was to explore the possible therapeutic effects, and underlying mechanism of baicalein in the treatment of asthma.MethodsFreely availabled atabases (e.g. OMIM, TTD, Genecards, BATMAN-TCM, STITCH 5.0, SEA, SwissTargetPrediction) and software (e.g. Ligplot 2.2.5 and PyMoL) were used for disease drug target prediction and molecular docking by network pharmacology. The efficacy and mechanism of action of baicalein in the treatment of asthma were validated using an ovalbumin (OVA)-induced asthma mouse model and molecular biology techniques.ResultsA total of 1655 asthma-related genes and 161 baicalein-related targets were identified from public databases. Utilizing common databases and software for network pharmacology and molecular docking analysis, seven potential target proteins for the therapeutic effects of baicalein on asthma were selected, including v-akt murine thymoma viral oncogene homolog 1 (AKT1), vascular endothelial growth factor A (VEGFA), epidermal growth factor receptor (EGFR), proto-oncogene tyrosine-protein kinase Src (SRC), mitogen-activated protein kinase 3 (MAPK3), matrix metallopeptidase 9 (MMP9), and MAPK1. In vivo, baicalein treatment via intraperitoneal injection at a dose of 50 mg/kg significantly reduced airway inflammation, collagen deposition, smooth muscle thickness, lung interleukin (IL)-4 and IL-13 levels, peripheral blood immunoglobulin (Ig)E levels, as well as the count and ratio of eosinophils in bronchoalveolar lavage fluid (BALF) in an OVA-induced asthma mouse model. Further validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting analysis revealed that the VEGF and EGFR signaling pathways involving VEGFA, MAPK1, MAPK3, and EGFR were inhibited by baicalein in the asthma mouse model.ConclusionBaicalein attenuates airway inflammation and airway remodeling through inhibition of VEGF and EGFR signaling pathways in an OVA-induced asthma mouse model. This will provide a new basis for the development of baicalein as a treatment for asthma and highlights the potential of network pharmacology and molecular docking in drug discovery and development.

Antibiotic therapy and association with oncological outcomes from targeted and immune-based therapy in hepatocellular carcinoma (HCC).

4089 Background: Immune checkpoint inhibitors (ICI) alone or in combination with tyrosine kinase (TKI) or VEGF pathway inhibitors (VEGFi) are therapeutic options in unresectable HCC (uHCC). Whether exposure to antibiotics (ATB), a consolidated adverse prognostic factor in ICI recipients, affects outcome in HCC remains unclear. Methods: FDA analysed patient-level data of 4098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or combinations (n = 584), TKI (N = 1968), VEGFi (n = 480) or placebo (n = 808) as part of 9 international clinical trials submitted to the US Food and Drug Administration in support of marketing applications. Associations for ATB exposure within 30 days before or after initiation of anti-cancer treatment (ATB) with overall (OS) and progression-free survival (PFS) were examined across therapeutic modality. Estimates were weighted by propensity score (PSW) using clinically relevant covariates. Results: Out of 4098 patients with uHCC mostly secondary to Hepatitis B (39%) or C (21%) infection, the majority were males (83%) with a median age of 64 (range 18-88), ECOG performance status of 0 (60%) and Child-Pugh A class (98%). Most patients had metastases (68%) but did not have macrovascular invasion (71%). Overall, 620 patients (15%) were ATB+, with comparable rates across placebo (12%), TKI (16%), VEGFi (15%), and ICI (16%). In the overall population, ATB was associated with shorter PFS (2.8 vs 3.9 months [m], HR 1.29, 95%CI 1.22-1.36) and OS (6.4 vs. 8.8 m; HR 1.36, 95%CI 1.29-1.43). In PSW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52, 95%CI 1.34-1.73), TKI (HR 1.29, 95%CI 1.19-1.39) and placebo (HR 1.23, 95%CI 1.11-1.37). Similar results were observed in PSW analyses of OS in patients treated with ICI (HR 1.22, 95%CI 1.08-1.38), TKI HR 1.40, 95%CI 1.30-1.52), and placebo (HR 1.40, 95%CI 1.25-1.57). Consistent outcomes were observed for ATB+ patients within ICI treatment subgroups, including patients treated with anti-PD-1 monotherapy (PFS HR 1.49, 95%CI 1.22-1.80; OS HR 1.31 1.02-1.68) and ICI combinations (PFS HR 1.50, 95%CI 1.26-1.77; OS HR 1.14 0.99-1.32). Conclusions: Unlike other oncological indications where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with inferior outcomes across a broad range of anti-cancer therapies for HCC and placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut liver axis remains to be demonstrated in translational studies.

PIK3R5 genetic predictors of hypertension induced by VEGF-pathway inhibitors.

No biomarkers are available to predict patients at risk of developing hypertension induced by VEGF-pathway inhibitors. This study aimed to identify predictive biomarkers of hypertension induced by these drugs using a discovery-replication approach. The discovery set included 140 sorafenib-treated patients (TARGET study) genotyped for 973 SNPs in 56 genes. The most statistically significant SNPs associated with grade ≥2 hypertension were tested for association with grade ≥2 hypertension in the replication set of a GWAS of 1039 bevacizumab-treated patients from four clinical trials (CALGB/Alliance). In the discovery set, rs444904 (G > A) in PIK3R5 was associated with an increased risk of sorafenib-induced hypertension (p = 0.006, OR = 3.88 95% CI 1.54-9.81). In the replication set, rs427554 (G > A) in PIK3R5 (in complete linkage disequilibrium with rs444904) was associated with an increased risk of bevacizumab-induced hypertension (p = 0.008, OR = 1.39, 95% CI 1.09-1.78). This study identified a predictive marker of drug-induced hypertension that should be evaluated for other VEGF-pathway inhibitors.ClinicalTrials.gov Identifier:NCT00073307 (TARGET).

Impact of systemic anticancertherapy in pediatric optic pathway glioma on visual function: A systematic review.

Pediatric optic pathway glioma (OPG) can seriously decrease visual function in the case of progression. Systemic anticancer therapy (SAT) is considered the treatment of first choice for unresectable OPG. New SAT modalities for the treatment of progressive OPG have been introduced in the last decade, including VEGF and MAPK pathway inhibition. This systematic review evaluated the effect of SAT on change in visual acuity and visual field in OPG. A systematic review was performed on SAT for OPG (January 1990 to August 2020). MEDLINE and EMBASE (Ovid) were searched for studies reporting on change in visual acuity and visual field after treatment with SAT for OPG. Overall, 11 series, including 358 patients, fulfilled the eligibility criteria. After follow-up of median 3.7 years (range: cessation of SAT- 8.2 years), improvement in binocular VA was found in 0-45% of studies, stability in 18-77% and a decrease in 0-82%. Two studies reported on change in visual field (improvement in 19% and 71% of patients), although either the change was not defined or the testing strategy was lacking. Considerable heterogeneity was present among the included studies, such as variety in the combinations of SAT administered, status of neurofibromatosis type 1, definition regarding change in visual acuity, 1- or 2-eye analysis, diversity in anatomic location, and extent of follow-up, all of which made meta-analysis inappropriate. This systematic review suggests that the impact of SAT in OPG on visual function is still unclear. The wide ranges reported on the efficacy of SAT and the observed heterogeneity highlight the need for prospective studies with uniform definitions of outcome parameters.

Abstract 1652: Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models

Abstract Glioblastoma (GBM) is the most common primary tumor arising in the central nervous system (CNS). The currently approved standard of care has transient clinical benefit as GBM tends to be exceedingly aggressive. Despite pronounced efforts to identify novel therapies, curative options for GBM do not exist and the survival rate of diagnosed patients is very low. Therefore, there is an urgent need for new treatment strategies, and one approach would be to co-target and thereby disrupt distinct hallmarks of cancer, aiming to elicit sustained therapeutic responses. We have assessed this concept by combining a tricyclic antidepressant -imipramine - with drugs targeting VEGF-A ligand or VEGF-Receptor in mice bearing de novo GBM. All monotherapies were ineffective. In notable contradistinction, we found that combinatorial regimens significantly increased survival benefit and regressed established tumors. Investigation of the basis for the therapeutic efficacy revealed that combining the VEGF pathway inhibitor with imipramine hyperactivated autophagy to the level of eliciting cancer cell-intrinsic autophagy-associated cell death, whilst modifying the tumor vasculature to be more normal-like. In addition, imipramine downregulated an M2-like phenotype of tumor-associated macrophages and reprogramed them to express chemokines attracting otherwise rare CD8 T cells, which were demonstrably contributing to the observed efficacy. As such, these hallmark co-targeting combinations served to reprogram the GBM microenvironment from immunosuppressive to pro-inflammatory, thereby sensitizing the tumors to immune checkpoint blockade, as evidenced by enhanced responses when an anti-PD-L1 therapy was included in the mix. The results to be presented will elaborate a provocative new therapeutic approach for glioblastoma that has prospect to motivate clinical evaluation in this daunting form of human cancer. Citation Format: Agnieszka Chryplewicz, Douglas Hanahan. Co-targeting distinct hallmark capabilities for therapeutic benefit in pre-clinical GBM models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1652.

Immunomodulatory Roles of VEGF Pathway Inhibitors in Renal Cell Carcinoma.

Immune checkpoint inhibitors (ICIs) in combination with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) have become a new standard of care in treatment-naïve patients with advanced renal cell carcinoma (RCC). The rationale for these combinations relies on the interplay between the immune and angiogenic systems. The angiogenic factors and their receptors can promote an immunosuppressive tumor microenvironment by a direct effect on the innate immune cells and adaptive immune cells, and byan indirect effect through their influence on endothelial cells. Antiangiogenic therapies counteract these immunosuppressive effects by increasing tumor infiltration of mature dendritic cells and effector T cells, and decreasing tumor infiltration of immunosuppressive cells such as regulatory T cells and myeloid-derived suppressor cells. The immunomodulatory properties of antiangiogenic therapies combined with ICIs may provide enhanced activity through various mechanisms of action. Different associations with ICIs such as programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors and antiangiogenic therapies such as VEGFR-TKI or bevacizumab have been tested and led to the approval of pembrolizumab plus axitinib and avelumab plus axitinib in the first-line treatment of patients with advanced RCC. Other VEGFR axis inhibitors and ICI combinations are currently being tested with promising results. More combinations of immune agents, including cancer vaccines and immunostimulatory agents, are also being evaluated in association with VEGFR-TKI. Defining the best combination for each patient as well as the optimal therapeutic sequence will be essential to guide treatment decisions in clinical practice.

Association of pathogenic germline variant KDR Q472H with angiogenesis and resistance to treatment in melanoma.

10060 Background: Preclinical data suggest that melanoma angiogenesis promotes resistance to MAPK-pathway (MAPKi) and immune checkpoint inhibitors (ICIs). However, phase II clinical trials of anti-angiogenic therapy in melanoma were disappointing. We previously identified a pathogenic germline variant Q472H in the kinase insert domain receptor [KDR Q472H; vascular endothelial growth factor receptor-2 (VEGFR-2)] in 35% of primary melanoma patients. We hypothesize that KDR Q472H promotes resistance to MAPKi or ICIs, and that combined MAPKi or ICI and VEGF pathway inhibition may improve outcomes in patients harboring the variant. Methods: Metastatic melanoma (MM) patient clinical data and biospecimens enrolled in the NYU Langone Medical Center Melanoma program were studied. KDR status was determined by TaqMan assays. Tumor microvessel density (MVD) was assessed by CD34 immunohistochemistry. The impact of KDR Q472H on the tumor microenvironment was determined by RNA-seq and Nanostring. Synergy between BRAF (dabrafenib) and VEGFR-2 (lenvatinib) inhibitors in KDR-genotyped MM cell lines was assessed using cell proliferation assays and the Chou-Talalay method. Synergy between ICIs and anti-VEGFR-2 was evaluated in vivo using a B16 melanoma model. Results: We studied 221 MM patients (38% KDR Q472H variants). KDR Q472H variant was significantly associated with higher tumor MVD (P = 0.002). Among the MAPKi-treated patients, KDR Q472H homozygotes had shorter median progression-free survival (PFS, 3.3 vs 9.7 months, P = 0.009) than KDR wild type (WT). In patients treated with anti-PD-1-based therapies, response rates were lower in KDR Q472H variant patients compared to WT (P = 0.012), with shorter median PFS (8.4 months vs not reached, P = 0.0443). Transcriptomic analyses identified an immunosuppressive phenotype in KDR Q472H tumors, with reduced expression of genes associated with chemotaxis, inflammation, T cell activity, and antigen presentation. Consistent with this finding, VEGFR-2 blockade in a KDR Q472H B16 mouse melanoma model augmented the anti-melanoma immune response. KDR Q472H cell lines displayed synergistic cytotoxicity with dabrafenib and lenvatinib, compared to KDR WT cells. Conclusions: Our data demonstrate that melanoma patients with pathogenic germline variant KDR Q472H may be more resistant to both ICIs and MAPKi. Anti-angiogenic therapy should be reconsidered within this specific subset of patients in prospective clinical trials.

118P - PIK3R5 genetic predictors of hypertension induced by VEGF-pathway inhibitors

BackgroundHypertension is one of the major side effect of VEGF-pathway inhibitors. There are no validated biomarkers to predict which cancer patients will develop hypertension. This study aimed to identify genetic predictors of hypertension induced by VEGF-pathway inhibitors. MethodsA two-step, discovery-validation approach was used. The discovery set included 140 renal cell carcinoma patients from the TARGET study treated with sorafenib (400mg twice daily) (PMID 30385613) and genotyped for 1,040 germline variants in 56 genes. The most statistically significant variant from the discovery set (chi-squared test) was tested in a validation set (cause-specific Cox model) consisting of 1,041 cancer patients treated with bevacizumab (10-15mg/kg every two-three weeks) and genotyped using GWAS microarray platforms. For both studies, grade ≥2 hypertension (CTCAE v. 3.0) was used as the endpoint. Genetic associations were adjusted for age and sex. ResultsIn the discovery set, the most statistically significant variant associated with hypertension in sorafenib-treated patients was rs444904 (G>A, P=0.006). The A allele of rs444904 (minor allele frequency, MAF 0.14) increased the risk of hypertension. In the validation set, the A allele of rs427554 (G>A, in complete linkage disequilibrium with rs444904) increased the risk of hypertension in bevacizumab-treated patients (P=0.008, MAF 0.11). rs444904 and rs427554 are intronic variants in PIK3R5. PIK3R5 encodes the regulatory subunit of PI3Kγ, which, when activated by VEGF, leads to nitric oxide (NO) production and vasodilation. These variants have been associated with decreased expression of PIK3R5 in blood (PMID 25954001), consistent with their effect in increasing the risk of hypertension. ConclusionsCommon genetic variants that could reduce PIK3R5 activity increase the risk of sorafenib- and bevacizumab-induced hypertension. In patients treated with these drugs, reduced activity or expression of PIK3R5 may lead to a reduction in NO production, resulting in vasoconstriction and hypertension. This study, for the first time, provides evidence for new predictive genetic markers of drug-induced hypertension that should be further evaluated for other VEGF-pathway inhibitors. Clinical trial identificationTARGET CALGB 80303 NCT00088894 CALGB 40503 NCT00601900 CALGB 40502 NCT00785291 CALGB 90401 NCT00110214. Legal entity responsible for the studyFederico Innocenti. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

P3.13-12 A Lung Adenocarcinoma with Concomitant EGFR and de novo MET Amplification Response Well to Combination of TKI and Bevacizumab

Patients with NSCLC who are carrying concomitant de novo EGFR and MET amplification were commonly reported to have poor response to therapy. Here, we presented a case of a patient harboring concomitant de novo MET and EGFR, who obtained favorable response to combinatorial therapy of TKI and bevacizumab. We presented a lung adenocarcinoma patient harboring dual EGFR-MET alterations, and evaluated his response to combinatorial therapy of TKI and bevacizumab. In vitro experiments were performed in HCC827(EGFR-19del) and HCC827-GR (EGFR-19del+MET amplification) cells to validate the effect of bevacizumab on MET pathway. A 44-year-old male stage IV lung adenocarcinoma with left lung tumor was detected harboring of EGFR-19del and MET amplification using PCR and FISH. The patient was treated with erlotinib+bevacizumab and achieved partial response (PR) with a PFS with 13 months. After PD, NGS performed on both tissue and plasma biopsies revealed that the patients obtained first-generation resistant mutation EGFR-T790M, concomitant with EGFR-19del. The patient was treated with osimertinib+bevacizumab and achieved PR. He developed PD again with a PFS of 10.2 months, and repeated biopsies sequencing identified concomitant EGFR-19del and MET amplification. Then, the patient was treated with crizotinib+bevacizumab and the best curative effect was stable disease. Four months later, he developed PD and the third biopsy still revealed positive EGFR-19del and MET amplification. The patient received osimertinib+crizotinib+bevacizumab and he achieved PR one month after treatment initiation. He is still under the treatment and the PFS is more than eight months. In vitro data revealed that, under gefitinib treatment, cell viability was higher in HCC827(EGFR-19del) than HCC827-GR (EGFR-19del+METamp). However, the patient harboring dual EGFR-MET alterations in this study obtained a PFS of 13 months to erlotinib, similar with patients with EGFR-19del only (mPFS was 13 months to erlotinib as reported), suggesting the efficacious treatment of EGFR-TKI and bevacizumab than TKI alone. We observed that VEGFR-2 was expressed at relatively high levels in HCC827-GR than other cell line without METamp, and VEGF pathway inhibition by bevacizumab resulted in decreased phospho-c-Met in HCC827-GR cell lines. This result provided in vitro evidence that bevacizumab can reduce MET pathway activation. This study provided basic knowledge and evidence for patients harboring concomitant EGFR and de novo MET amplification who may obtain favorable response to combinatorial treatment of TKI and bevacizumab. Encouraging antitumor activity of TKI+bevacizumab support further development of this combination for patients with advanced NSCLC and other solid tumors.

EL24 - Managements of oncologic emergency occurred in patients with advanced cancer

Various oncologic emergencies, such as severe infection due to myelosuppression, renal failure, tumor lysis syndrome, electrolytic abnormalities, neurologic disturbances, and so on, sometimes occur in patients with advanced cancer. In addition, since an introduction of many new molecularly targeted drugs including VEGF-pathway inhibitors and immune checkpoint inhibitors, cardiovascular adverse events and immune-related adverse events have recently attracted a greater attention in an area of oncology. Here, I introduce current topics about the management of the various oncologic emergencies observed in patients with cancer who receive cancer drug therapy.

Targeting the vasculature of tumours: combining VEGF pathway inhibitors with radiotherapy.

The development of blood vessels by the process of angiogenesis underpins the growth and metastasis of many tumour types. Various angiogenesis inhibitors targeted against vascular endothelial growth factor A (VEGF-A) and its receptors have entered the clinic more than a decade ago. However, despite substantial clinical improvements, their overall efficacy proved to be significantly lower than many of the pre-clinical studies had predicted. Antiangiogenic agents have been combined with chemotherapy, radiotherapy and more recently immunotherapy in many pre-clinical and clinical studies in an effort to improve their efficacy. To date, only their use alongside chemotherapy is approved as part of standard treatment protocols. Most pre-clinical studies have reported improved tumour control from the addition of antiangiogenic therapies to radiotherapy and progress has been made in unravelling the complex mechanisms through which VEGF inhibition potentiates radiotherapy responses. However, the efficacy of this combination is variable, and many questions still remain as to how best to administer the two modalities to achieve optimal response and minimal toxicity. One important limiting factor is that, unlike some other targeted therapies, antiangiogenic agents are not administered to selected patient populations, since biomarkers for identifying responders have not yet been established. Here, we outline VEGF biology and review current approaches that aim to identify biomarkers for stratifying patients for treatment with angiogenesis inhibitors. We also discuss current progress in elucidating mechanisms of interaction between radiotherapy and VEGF inhibitors. Ongoing clinical trials will determine whether these combinations will ultimately improve treatment outcomes for cancer patients.

Tumor-Independent Host Secretomes Induced By Angiogenesis and Immune-Checkpoint Inhibitors.

The levels of various circulating blood proteins can change in response to cancer therapy. Monitoring therapy-induced secretomes (TIS) may have use as biomarkers for establishing optimal biological effect (such as dosing) or identifying sources of toxicity and drug resistance. Although TIS can derive from tumor cells directly, nontumor "host" treatment responses can also impact systemic secretory programs. For targeted inhibitors of the tumor microenvironment, including antiangiogenic and immune-checkpoint therapies, host TIS could explain unexpected collateral "side effects" of treatment. Here, we describe a comparative transcriptomic and proteomic analysis of host TIS in tissues and plasma from cancer-free mice treated with antibody and receptor tyrosine kinase inhibitors (RTKI) of the VEGF, cMet/ALK, and PD-1 pathways. We found that all cancer therapies elicit TIS independent of tumor growth, with systemic secretory gene change intensity higher in RTKIs compared with antibodies. Our results show that host TIS signatures differ between drug target, drug class, and dose. Notably, protein and gene host TIS signatures were not always predictive for each other, suggesting limitations to transcriptomic-only approaches to clinical biomarker development for circulating proteins. Together, these are the first studies to assess and compare "off-target" host secretory effects of VEGF and PD-1 pathway inhibition that occur independent of tumor stage or tumor response to therapy. Testing treatment impact on normal tissues to establish host-mediated TIS signatures (or "therasomes") may be important for identifying disease agnostic biomarkers to predict benefits (or limitations) of drug combinatory approaches. Mol Cancer Ther; 17(7); 1602-12. ©2018 AACR.

Effect of the monoclonal antibody TRC105 in combination with Sunitinib on renal tumor derived endothelial cells.

Anti-angiogenic therapy is an important strategy to limit growth, development and expansion of solid tumors. However, resistance to VEGF-targeting agents may develop, due to activation of alternative pro-angiogenic pathways, indicating the need of multiple target strategy. Here we obtained tumor endothelial cells (TEC) either from total renal carcinomas or from renal cancer stem cells (CSC-TEC) and we tested the effect of a CD105 targeting monoclonal antibody, TRC105, alone or in association with anti-VEGF drugs. We demonstrated that TRC105 impaired the ability of TEC and CSC-TEC to organize in tubular structures, whereas it did not limit proliferation or survival. The combination of TRC105 with different anti-angiogenic drugs showed a synergistic effect of TRC105 only in combination with the tyrosine kinase inhibitor Sunitinib. In particular, TRC105 plus Sunitinib reduced tubulogenesis, proliferation and survival of CSC-TEC and tumor-derived TEC in a similar manner. At a molecular level, we showed that the combination of TRC105 and Sunitinib induced the phosphorylation of Smad 2/3 to promote endothelial cell death. Moreover, TRC105 enhanced the inhibitory effect of Sunitinib on VEGF signaling and reduced VEGFR2-Akt-Creb activation, suggesting a molecular cooperation between the two drugs. Our results highlight that the combined inhibition of VEGF and TGF-β pathway may have a potential use in renal cell carcinoma therapy.

Preliminary results for avelumab plus axitinib as first-line therapy in patients with advanced clear-cell renal-cell carcinoma (JAVELIN Renal 100): an open-label, dose-finding and dose-expansion, phase 1b trial

The combination of an immune checkpoint inhibitor and a VEGF pathway inhibitor to treat patients with advanced renal-cell carcinoma might increase the clinical benefit of these drugs compared with their use alone. Here, we report preliminary results for the combination of avelumab, an IgG1 monoclonal antibody against the programmed cell death protein ligand PD-L1, and axitinib, a VEGF receptor inhibitor approved for second-line treatment of advanced renal-cell carcinoma, in treatment-naive patients with advanced renal-cell carcinoma. The JAVELIN Renal 100 study is an ongoing open-label, multicentre, dose-finding, and dose-expansion, phase 1b study, done in 14 centres in the USA, UK, and Japan. Eligible patients were aged 18 years or older (≥20 years in Japan) and had histologically or cytologically confirmed advanced renal-cell carcinoma with clear-cell component, life expectancy of at least 3 months, an Eastern Cooperative Oncology Group performance status of 1 or less, received no previous systemic treatment for advanced renal cell carcinoma, and had a resected primary tumour. Patients enrolled into the dose-finding phase received 5 mg axitinib orally twice daily for 7 days, followed by combination therapy with 10 mg/kg avelumab intravenously every 2 weeks and 5 mg axitinib orally twice daily. Based on the pharmacokinetic data from the dose-finding phase, ten additional patients were enrolled into the dose-expansion phase and assigned to this regimen. The other patients in the dose-expansion phase started taking combination therapy directly. The primary endpoint was dose-limiting toxicities in the first 4 weeks (two cycles) of treatment with avelumab plus axitinib. Safety and antitumour activity analyses were done in all patients who received at least one dose of avelumab or axitinib. This trial is registered with ClinicalTrials.gov, number NCT02493751. Between Oct 30, 2015, and Sept 30, 2016, we enrolled six patients into the dose-finding phase and 49 into the dose-expansion phase of the study. One dose-limiting toxicity of grade 3 proteinuria due to axitinib was reported among the six patients treated during the dose-finding phase. At the cutoff date (April 13, 2017), six (100%, 95% CI 54-100) of six patients in the dose-finding phase and 26 (53%, 38-68) of 49 patients in the dose-expansion phase had confirmed objective responses (32 [58%, 44-71] of all 55 patients). 32 (58%) of 55 patients had grade 3 or worse treatment-related adverse events, the most frequent being hypertension in 16 (29%) patients and increased concentrations of alanine aminotransferase, amylase, and lipase, and palmar-plantar erythrodysaesthesia syndrome in four (7%) patients each. Six (11%) of 55 patients died before data cutoff, five (9%) due to disease progression and one (2%) due to treatment-related autoimmune myocarditis. At the end of the dose-finding phase, the maximum tolerated dose established for the combination was avelumab 10 mg/kg every 2 weeks and axitinib 5 mg twice daily. The safety profile of the combination avelumab plus axitinib in treatment-naive patients with advanced renal-cell carcinoma seemed to be manageable and consistent with that of each drug alone, and the preliminary data on antitumour activity are encouraging. A phase 3 trial is assessing avelumab and axitinib compared with sunitinib monotherapy. Pfizer and Merck.

AB010. Promotion of BMP9/ALK1 quiescence signaling for the prevention of diabetic macular edema (DME)

Background: Sight-threatening diabetic macular edema (DME) is caused by increased microvascular permeability. While few direct vascular targeting strategies are available, VEGF pathway inhibition has shown to be effective in reducing retinal vascular leakage but is associated with non-negligible side effects. Thus, more options are needed. Vascular specific Activin-like kinase receptor type I (ALK1) pathway and its circulating ligand Bone morphogenetic protein-9 (BMP9) is known for its potent quiescent and stabilizing effect on the vasculature. However, little is known about this pathway in the context of microvascular permeability associated with diabetes. We hypothesize that BMP9/ALK1 pathway is inhibited in diabetic (DB) retinas leading to vascular destabilization and leakage and that its activation could re-establish proper vascular endothelial barrier functions (EBF).

Safety and efficacy of axitinib (axi) in combination with pembrolizumab (pembro) in patients (pts) with advanced renal cell cancer (aRCC).

579 Background: Prior studies combining programmed death-1 (PD-1) checkpoint inhibitors with tyrosine kinase inhibitors of the vascular endothelial growth factor (VEGF) pathway have been characterized by excess toxicity precluding further development. We hypothesized that a combination of axi, a more selective VEGF-pathway inhibitor, with pembro (anti-PD-1) would be well tolerated and yield antitumour activity in treatment-naïve pts with aRCC. Methods: This ongoing open-label phase Ib study of axi/pembro comprised a dose-finding phase to determine the maximum tolerated dose and dose expansion phase. Axi 5 mg was administered orally twice daily with pembro 2 mg/kg administered intravenously every 3 weeks. Tumors were assessed, using RECIST v1.1, at baseline, week 12, and every 6 weeks thereafter. The primary endpoint was dose-limiting toxicity (DLT) during the first 2 cycles (6 weeks), with secondary endpoints evaluating safety, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: Between 23 Sept 2014 and 13 Oct 2015, 52 treatment-naïve pts with aRCC were enrolled. No unexpected toxicities were observed. Three DLTs were reported among the 11 pts treated in the dose-finding phase: transient ischemic attack (n = 1) and < 75% of planned axi dosage administered due to treatment-related toxicity (n = 2). At cutoff date (March 30, 2017), 25 pts were receiving study treatment. Most common (≥10%) grade ≥3 all-causality AEs included hypertension (23%), diarrhoea (10%) and fatigue (10%). Most common ( > 10%) potentially immune-related AEs included diarrhoea (29%), increased alanine aminotransferase (17%), or aspartate aminotransferase (13%), hypothyroidism (13%), and fatigue (12%). ORR was 73.1% (95% confidence intervals [CIs], 59.0–84.4). Median (95% CI) PFS was 20.9 (15.4–not evaluable) months. OS data were not mature at minimum follow-up period of 17.6 months, with 6 treatment-unrelated deaths reported. Conclusions: The combination axi/pembro is tolerable and exhibits promising antitumour activity in treatment-naïve pts with aRCC. A randomized phase 3 trial comparing the combination to sunitinib monotherapy is underway. Clinical trial information: NCT02133742.

Axitinib in combination with pembrolizumab in patients with advanced renal cell cancer: a non-randomised, open-label, dose-finding, and dose-expansion phase 1b trial

Previous studies combining PD-1 checkpoint inhibitors with tyrosine kinase inhibitors of the VEGF pathway have been characterised by excess toxicity, precluding further development. We hypothesised that axitinib, a more selective VEGF inhibitor than others previously tested, could be combined safely with pembrolizumab (anti-PD-1) and yield antitumour activity in patients with treatment-naive advanced renal cell carcinoma. In this ongoing, open-label, phase 1b study, which was done at ten centres in the USA, we enrolled patients aged 18 years or older who had advanced renal cell carcinoma (predominantly clear cell subtype) with their primary tumour resected, and at least one measureable lesion, Eastern Cooperative Oncology Group performance status 0-1, controlled hypertension, and no previous systemic therapy for renal cell carcinoma. Eligible patients received axitinib plus pembrolizumab in a dose-finding phase to estimate the maximum tolerated dose, and additional patients were enrolled into a dose-expansion phase to further establish safety and determine preliminary efficacy. Axitinib 5 mg was administered orally twice per day with pembrolizumab 2 mg/kg given intravenously every 3 weeks. We assessed safety in all patients who received at least one dose of axitinib or pembrolizumab; antitumour activity was assessed in all patients who received study treatment and had an adequate baseline tumour assessment. The primary endpoint was investigator-assessed dose-limiting toxicity during the first two cycles (6 weeks) to estimate the maximum tolerated dose and recommended phase 2 dose. This study is registered with ClinicalTrials.gov, number NCT02133742. Between Sept 23, 2014, and March 25, 2015, we enrolled 11 patients with previously untreated advanced renal cell carcinoma to the dose-finding phase and between June 3, 2015, and Oct 13, 2015, we enrolled 41 patients to the dose-expansion phase. All 52 patients were analysed together. No unexpected toxicities were observed. Three dose-limiting toxicities were reported in the 11 patients treated during the 6-week observation period (dose-finding phase): one patient had a transient ischaemic attack and two patients were only able to complete less than 75% of the planned axitinib dose because of treatment-related toxicity. At the data cutoff date (March 31, 2017), 25 (48%) patients were still receiving study treatment. Grade 3 or worse treatment-related adverse events occurred in 34 (65%) patients; the most common included hypertension (n=12 [23%]), diarrhoea (n=5 [10%]), fatigue (n=5 [10%]), and increased alanine aminotransferase concentration (n=4 [8%]). The most common potentially immune-related adverse events (probably related to pembrolizumab) included diarrhoea (n=15 [29%]), increased alanine aminotransferase concentration (n=9 [17%]) or aspartate aminotransferase concentration (n=7 [13%]), hypothyroidism (n=7 [13%]), and fatigue (n=6 [12%]). 28 (54%) patients had treatment-related serious adverse events. At data cutoff, 38 (73%; 95% CI 59·0-84·4) patients achieved an objective response (complete or partial response). The treatment combination of axitinib plus pembrolizumab is tolerable and shows promising antitumour activity in patients with treatment-naive advanced renal cell carcinoma. Whether or not the combination works better than a sequence of VEGF pathway inhibition followed by an anti-PD-1 therapy awaits the completion of a phase 3 trial comparing axitinib plus pembrolizumab with sunitinib monotherapy (NCT02853331). Pfizer Inc.

Nintedanib treatment delays prostate dorsolateral lobe cancer progression in the TRAMP model: contribution to the epithelial‐stromal interaction balance

Prostate cancer (PCa) progression mechanism has been linked to epithelial proliferation, tumor invasion ability, and growth factors. Nintedanib (BIBF 1120) has been reported as being FGF and VEGF pathway inhibitors, exhibiting antitumor activity. Thus, the objective herein was to characterize the early Nintedanib treatment effects on the structure and molecules involved in the basal membrane, the extracellular matrix (ECM) maintenance, in addition to the angiogenesis and mitogenic processes at different grades of prostatic tumor development in TRAMP mice. Therefore, 45 male TRAMP mice were divided into control groups: 8-week-old mice (TC8), 12-week-old mice (TC12), and 16-week-old mice (TC16); and treated groups with 10 mg/kg/day Nintedanib dose for 4 weeks. The treated groups were euthanized at 12 (TN12) and 16 (TN16) weeks of age. Samples from the dorsolateral lobe were collected and processed for light microscopy, immunohistochemistry, Western blotting, and microvessel density analysis. The results showed that early Nintedanib treatment led to an increase of healthy epithelium frequency and a reduction of LGPIN and a maximum vascularization density in the TN12 group. Also, treatment led to a well-differentiated adenocarcinoma decrease and an α and β dystroglycan and also laminin 1 increase in the TN16 group. IGFR1 decreased in the TN16 group. To conclude, early Nintedanib treatment led to a reduction in cancer severity, interfering in both ECM compounds and angiogenesis process to then contribute to a balance, not only in the prostatic epithelium and stroma, but also in the epithelial-stromal interaction during PCa progression.