Preclinical Study of a Combination of Erlotinib and Bevacizumab in Early Stages of Unselected Non-Small Cell Lung Cancer Patient-Derived Xenografts

Comparing Efficacy of Erlotinib and Bevacizumab Combination with Erlotinib Monotherapy in Patients with Advanced Non-Small Cell Lung Cancer (NSCLC): A Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to assess and contrast the efficacy and safety of combining erlotinib and bevacizumab with erlotinib alone in the treatment of patients with advanced non-small cell lung cancer (NSCLC). The authors searched databases such as PubMed, Medline, Scopus, and Cochrane Central Register of Controlled Trials for randomized control trials (RCTs) comparing erlotinib plus bevacizumab with erlotinib in NSCLC patients. The overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs) were the outcomes of interest. The pooled hazard ratio (HR) and relative risk (RR) were estimated utilizing both fixed- and random-effect models. Methodological quality of the included studies was assessed using the Cochrane Risk of Bias tool. Nine studies comprising 1698 patients with NSCLC were included in this meta-analysis, of whom 850 were treated with erlotinib plus bevacizumab, and 848 with erlotinib. The erlotinib plus bevacizumab combination significantly prolonged PFS (HR, 0.62, 95% CI: 0.56, 0.70, p < 0.00001) but did not show any significant improvement in OS (HR, 0.95; 95% CI: 0.83, 1.07, p = 0.39) and ORR (HR, 1.10; 95% CI: 0.98, 1.24, p = 0.09). Increased risks of hypertension (RR, 5.15; 95% CI: 3.59, 7.39; p < 0.00001), proteinuria (RR, 10.54; 95% CI: 3.80, 29.20; p < 0.00001) and grade 3 and higher AEs (RR, 2.09; 95% CI: 1.47, 2.97; p < 0.00001) were observed with the erlotinib-plus-bevacizumab combination compared to erlotinib monotherapy. On subgroup analyses, the erlotinib plus bevacizumab combination improved PFS only. Combining erlotinib and bevacizumab has been shown to improve PFS in advanced NSCLC patients but did not show any significant OS and ORR benefits. Furthermore, risks of hypertension, proteinuria, and grade 3 or higher AEs were greater with the erlotinib-and-bevacizumab combination.

A Molecularly Characterized Preclinical Platform of Subcutaneous Renal Cell Carcinoma (RCC) Patient-Derived Xenograft Models to Evaluate Novel Treatment Strategies

Renal cell carcinoma (RCC) is a kidney cancer with an onset mainly during the sixth or seventh decade of the patient’s life. Patients with advanced, metastasized RCC have a poor prognosis. The majority of patients develop treatment resistance towards Standard of Care (SoC) drugs within months. Tyrosine kinase inhibitors (TKIs) are the backbone of first-line therapy and have been partnered with an immune checkpoint inhibitor (ICI) recently. Despite the most recent progress, the development of novel therapies targeting acquired TKI resistance mechanisms in advanced and metastatic RCC remains a high medical need. Preclinical models with high translational relevance can significantly support the development of novel personalized therapies. It has been demonstrated that patient-derived xenograft (PDX) models represent an essential tool for the preclinical evaluation of novel targeted therapies and their combinations. In the present project, we established and molecularly characterized a comprehensive panel of subcutaneous RCC PDX models with well-conserved molecular and pathological features over multiple passages. Drug screening towards four SoC drugs targeting the vascular endothelial growth factor (VEGF) and PI3K/mTOR pathway revealed individual and heterogeneous response profiles in those models, very similar to observations in patients. As unique features, our cohort includes PDX models from metastatic disease and multi-tumor regions from one patient, allowing extended studies on intra-tumor heterogeneity (ITH). The PDX models are further used as basis for developing corresponding in vitro cell culture models enabling advanced high-throughput drug screening in a personalized context. PDX models were subjected to next-generation sequencing (NGS). Characterization of cancer-relevant features including driver mutations or cellular processes was performed using mutational and gene expression data in order to identify potential biomarker or treatment targets in RCC. In summary, we report a newly established and molecularly characterized panel of RCC PDX models with high relevance for translational preclinical research.

Breaking the crosstalk of the Cellular Tumorigenic Network by low-dose combination therapy in lung cancer patient-derived xenografts

Non-small cell lung cancer (NSCLC) is commonly diagnosed at advanced stages limiting treatment options. Although, targeted therapy has become integral part of NSCLC treatment therapies often fail to improve patient's prognosis. Based on previously published criteria for selecting drug combinations for overcoming resistances, NSCLC patient-derived xenograft (PDX) tumors were treated with a low dose combination of cabozantinib, afatinib, plerixafor and etoricoxib. All PDX tumors treated, including highly therapy-resistant adeno- and squamous cell carcinomas without targetable oncogenic mutations, were completely suppressed by this drug regimen, leading to an ORR of 81% and a CBR of 100%. The application and safety profile of this low dose therapy regimen was well manageable in the pre-clinical settings. Overall, this study provides evidence of a relationship between active paracrine signaling pathways of the Cellular Tumorigenic Network, which can be effectively targeted by a low-dose multimodal therapy to overcome therapy resistance and improve prognosis of NSCLC.

A phase II study of carboplatin, pemetrexed, and bevacizumab followed by erlotinib and bevacizumab maintenance for non-squamous non-small cell lung cancer with wild-type EGFR (HOT1101)

BACKGROUND

This study evaluated the efficacy and safety of switch maintenance erlotinib and bevacizumab after induction therapy with carboplatin/pemetrexed/bevacizumab for non-squamous non-small cell lung cancer (NSCLC) with wild-type EGFR.

METHODS

Enrolled patients had treatment-naïve, advanced non-squamous NSCLC with wild-type EGFR. Carboplatin [area under the curve (AUC) 5.0], pemetrexed (500 mg/m2) and bevacizumab (15 mg/kg) were administered on day 1 every 3 weeks for 4-6 cycles. Maintenance therapy with erlotinib (150 mg/body) on day 1 through 21 plus bevacizumab on day 1 every 3 weeks was continued until disease progression or unacceptable toxicity. The primary endpoint was 6-month progression-free survival (PFS); secondary endpoints included overall survival (OS), overall response rate (ORR), toxicity, and quality of life (QOL).

RESULTS

Fifty-one patients were enrolled between September 2011 and June 2014. The median number of cycles for induction and maintenance therapy was 4 (range 1-6) and 4 (range 1-20). Twenty-nine patients (58%) received maintenance therapy. The 6-month PFS rate was 59.5% [95% confidence interval (CI) 45.0-72.6%]. The ORR was 48.0% (95% CI 34.8-61.5%), and disease control rate was 86.0% (95% CI 73.8-93.0%). The median PFS and OS were 6.5 months (95% CI 5.8-7.2 months) and 21.4 months (95% CI 15.9-26.9 months), respectively. Although grades ≥ 3 adverse events were observed in 33 patients (66.0%), most were hematologic; there was no febrile neutropenia. QOL was maintained throughout treatment.

CONCLUSIONS

Carboplatin/pemetrexed/bevacizumab followed by erlotinib and bevacizumab maintenance showed modest efficacy and was well tolerated in non-squamous NSCLC patients with wild-type EGFR.

TRIAL REGISTRATION

UMIN000005872.

VEGF as a potential target in lung cancer

Introduction The vascular endothelial growth factor A (VEGF) is the main mediator of angiogenesis. In addition, VEGF contributes to cancer growth and metastasis directly targeting tumor cells. VEGF overexpression and/or high VEGF serum levels have been reported in lung cancer. Areas covered We searched Pubmed for relevant preclinical studies with the terms 'lung cancer' 'VEGF' and 'in vivo'. We also searched the Clinicaltrials.gov database, the FDA and the EMA websites for the most recent updates on clinical development of anti-VEGF agents. Expert opinion VEGF plays an important role in sustaining the development and progression of lung cancer and it might represent an attractive target for therapeutic strategies. Nevertheless, clinical trials failed to attend the promising expectations deriving from preclinical studies with anti-VEGF agents. To improve the efficacy of anti-VEGF therapies in lung cancer, potential strategies might be the employment of combinatory therapies with immune checkpoint inhibitors or agents that inhibit signaling pathways and proangiogenic factors activated in response to VEGF blockade, and the identification of novel targets in the VEGF cascade. Finally, the identification of predictive markers might help to select patients who are more likely to respond to anti-angiogenic drugs.

Apatinib enhances antitumour activity of EGFR-TKIs in non-small cell lung cancer with EGFR-TKI resistance

BACKGROUND

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-rechallenged therapy for EGFR-mutant non-small cell lung cancer (NSCLC) patients who acquired resistance showed moderate efficacy. Considering the high interrelation between EGFR and vascular endothelial growth factor/vascular endothelial growth factor receptor (VEGF/VEGFR) pathways, we firstly evaluated EGFR-TKI combined with apatinib (a highly selective VEGFR2 inhibitor) in EGFR-TKI-resistant model and patients.

METHODS

Effects of apatinib, gefitinib and gefitinib plus apatinib were assessed on four NSCLC cell lines (A549 with wild-type EGFR, H1975 harbouring L858R and T790M, H1650 and HCC827 harbouring E746_A750 deletion) and xenograft model of acquired resistance that was established by injecting H1975 cells. Furthermore, we retrospectively evaluated EGFR-TKI rechallenge with apatinib in 16 patients.

RESULTS

Gefitinib plus apatinib strengthened the effect of gefitinib and apatinib alone on the four NSCLC cell lines, and H1975 was the most susceptible one. Co-administration delayed the tumour growth than mono-therapy in the xenograft model and had better effect on inhibiting the activation of EGFR and VEGFR2 and expression of CD31 (an angiogenesis marker) and vascular endothelial growth factor A (an important pro-angiogenesis factor in the tumour microenvironment). Changes in protein expression of protein kinase B/mammalian target of rapamycin and extracellular signal-regulated kinase pathways demonstrated the potent inhibitory effect on the pro-survival signalling pathways by combined therapy. EGFR-TKI rechallenge with apatinib achieved a median progression-free survival of 4.60 months (95% confidence interval, 2.23-12.52 months) in the patients.

CONCLUSIONS

Apatinib significantly potentiated the antitumour effect of gefitinib in NSCLC with T790M-related EGFR-TKI resistance both in vivo and vitro. EGFR-TKI rechallenge with apatinib might represent a new option for NSCLC with T790M or unknown resistance mechanism.

Novel patient-derived xenograft mouse model for pancreatic acinar cell carcinoma demonstrates single agent activity of oxaliplatin

BACKGROUND

Pancreatic acinar cell carcinoma (PACC) is a rare malignancy, accounting for <1 % of all pancreatic neoplasms. Very few retrospective studies are available to help guide management. We previously reported the case of a patient with metastatic PACC who achieved prolonged survival following doxorubicin treatment. Personalized treatment was based on molecular and in vitro data collected from primary cells developed from their liver metastasis. We now report the characterization of a patient derived tumor xenograft (PDTX) mouse model that originated from this patient's PACC liver metastasis.

METHODS

Fragments of biopsy tissue (5 mm(3)) from PACC liver metastasis were implanted into athymic nude mice. Tumors were grown and passaged from the host mice into new mice to be tested for therapeutic response. Immuno-histochemical (IHC) biomarkers were used to confirm that the PDTX model represents human PACC. The antitumor activities of multiple drugs (5-FU, irinotecan, oxaliplatin, gemcitabine, bevacizumab, erlotinib, doxorubicin and imatinib) were tested. Tumor size was measured over 74 days or until they reached an endpoint volume of ~800 mm(3). Tests to measure serum lipase levels and histological analyses of tumor tissues were also conducted to assess PACC progression and re-differentiation.

RESULTS

The model presented here expresses the same IHC markers found in human PACC. In the chemotherapy study, oxaliplatin produced a prolonged durable growth response associated with increased apoptosis, decreased serum lipase levels and increased healthy acinar cells. Bevacizumab also produced a significant growth response, but the effect was not prolonged as demonstrated by oxaliplatin treatment. The other chemotherapies had moderate to little effect, particularly after treatment ceased. Mutations in DNA repair genes are common in PACC and increase tumor susceptibility to oxaliplatin. To explore this we performed IHC and found no nuclear expression of BRCA2 in our model, indicating a mutation affecting nuclear localization. Gene sequencing confirms BRCA2 has a homozygous gene deletion on Exon 10, which frequently causes a protein truncation.

CONCLUSIONS

In summary, we report the development and characterization of the first and only preclinical PACC PDTX model. Here we show sustained anti-tumor activity of single agent oxaliplatin, a compound that is more effective in tumors that harbor mutations in DNA repair genes. Our data shows that BRCA2 is mutated in our PACC model, which could contribute to the oxaliplatin sensitivity observed. Further studies on this rare PACC model can serve to elucidate other novel therapies, biomarkers, and molecular mechanisms of signaling and drug resistance.