Randomized Phase II trial of nintedanib, afatinib and sequential combination in castration-resistant prostate cancer

New Therapeutic Perspectives in Prostate Cancer: Patient-Derived Organoids and Patient-Derived Xenograft Models in Precision Medicine

One of the major goals in the advancement of basic cancer research focuses on the development of new anticancer therapies. To understand the molecular mechanisms of cancer progression, acquired drug resistance, and the metastatic process, the use of preclinical in vitro models that faithfully summarize the properties of the tumor in patients is still a necessity. The tumor is represented by a diverse group of cell clones, and in recent years, to reproduce in vitro preclinical tumor models, monolayer cell cultures have been supplanted by patient-derived xenograft (PDX) models and cultured organoids derived from the patient (PDO). These models have proved indispensable for the study of the tumor microenvironment (TME) and its interaction with tumor cells. Prostate cancer (PCa) is the most common neoplasia in men in the world. It is characterized by genomic instability and resistance to conventional therapies. Despite recent advances in diagnosis and treatment, PCa remains a leading cause of cancer death. Here, we review the studies of the last 10 years as the number of papers is growing very fast in the field. We also discuss the discovered limitations and the new challenges in using the organoid culture system and in using PDXs in studying the prostate cancer phenotype, performing drug testing, and developing anticancer molecular therapies.

Nintedanib in an elderly non-small-cell lung cancer patient with severe steroid-refractory checkpoint inhibitor-related pneumonitis: A case report and literature review

Immune checkpoint inhibitors tremendously improve cancer prognosis; however, severe-grade immune-related adverse events may cause premature death. Current recommendations for checkpoint inhibitor-related pneumonitis (CIP) treatment are mainly about immunosuppressive therapy, and anti-fibrotic agents are also needed, especially for patients with poor response to corticosteroids and a longer pneumonitis course. This is because fibrotic changes play an important role in the pathological evolution of CIP. Here, we report a case demonstrating that nintedanib is a promising candidate drug for CIP management or prevention, as it has potent anti-fibrotic efficacy and a safety profile. Moreover, nintedanib could partially inhibit tumor growth in patients with non-small-cell lung cancer, and its efficacy can be improved in combination with other anti-tumor therapies.

Identification of a lncRNA based signature for pancreatic cancer survival to predict immune landscape and potential therapeutic drugs

Pancreatic cancer is one major digestive malignancy with a poor prognosis. Given the clinical importance of lncRNAs, developing a novel molecular panel with lncRNAs for pancreatic cancer has great potential. As a result, an 8-lncRNA-based robust prognostic signature was constructed using a random survival forest model after examing the expression profile and prognostic significance of lncRNAs in the PAAD cohort from TCGA. The efficacy and effectiveness of the lncRNA-based signature were thoroughly assessed. Patients with high- and low-risk defined by the signature underwent significantly distinct OS expectancy. Most crucially the training group’s AUCs of ROC approached 0.90 and the testing group similarly had the AUCs above 0.86. The lncRNA-based signature was shown to behave as a prognostic indicator of pancreatic cancer, either alone or simultaneously with other factors, after combined analysis with other clinical-pathological factors in Cox regression and nomogram. Additionally, using GSEA and CIBERSORT scoring methods, the immune landscape and variations in biological processes between high- and low-risk subgroups were investigated. Last but not least, drug databases were searched for prospective therapeutic molecules targeting high-risk patients. The most promising compound were Afatinib, LY-303511, and RO-90-7501 as a result. In conclusion, we developed a novel lncRNA based prognostic signature with high efficacy to stratify high-risk pancreatic cancer patients and screened prospective responsive drugs for targeting strategy.

Evaluation of the therapeutic potential of masitinib and expression of its specific targets c-Kit, PDGFR-α, PDGFR-β, and Lyn in canine prostate cancer cell lines

Canine prostate cancer is classified into adenocarcinoma, transitional cell carcinoma with prostatic involvement, and mixed forms. Early metastatic spread leads to poor prognosis and limited treatment options. Masitinib is approved for the treatment of canine mast cell tumours and inhibits tyrosine kinase c-Kit, tyrosine-protein kinase Lyn (Lyn), and platelet-derived growth factor receptors alpha and beta (PDGFR-α, PDGFR-β), which are known to be expressed in canine prostate cancer. The aim of this study was to evaluate masitinib in an in vitro model consisting of cell lines from primary prostate adenocarcinoma, the associated lymph node metastasis of the same patient, and transitional cell carcinoma. To assess the suitability of the model system, the targets of masitinib were investigated by immunocytochemistry in the cell lines and by immunohistochemistry in the respective formalin-fixed, paraffin-embedded (FFPE) original neoplastic tissue. After exposure to masitinib, cell viability, cell count, apoptosis induction, and protein expression of c-Kit, Lyn, PDGFR-α, and PDGFR-β were assessed. To hedge the efficacy, two application protocols of masitinib (single application or 12-h double-dose regimen) were compared. Immunocytochemical and immunohistochemical analysis revealed increased Lyn, PDGFR-α, and PDGFR-β expression in cell lines and FFPE original neoplastic tissue compared to healthy prostate tissue. Masitinib exposure increased apoptosis, while the cell counts and cell viability decreased in a dose- and application interval-dependent manner, with increased impact in the 12-h double-dose regimen. These in vitro effects of masitinib in canine prostate cancer and associated metastasis support further in vivo research and modifications of the clinical treatment protocol in future studies.

Targeting the PDGF/PDGFR signaling pathway for cancer therapy: A review

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are expressed in a variety of tumors. Activation of the PDGF/PDGFR signaling pathway is associated with cancer proliferation, metastasis, invasion, and angiogenesis through modulating multiple downstream pathways, including phosphatidylinositol 3 kinase/protein kinase B pathway and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Therefore, targeting PDGF/PDGFR signaling pathway has been demonstrated to be an effective strategy for cancer therapy, and accordingly, some great progress has been made in this field in the past few decades. This review will focus on the PDGF isoforms and their binding with the related PDGFRs, the PDGF/PDGFR signaling and regulation, and especially present strategies and inhibitors developed for cancer therapy, and the related clinical benefits and side effects.

HER3 Is an Actionable Target in Advanced Prostate Cancer

It has been recognized for decades that ERBB signaling is important in prostate cancer, but targeting ERBB receptors as a therapeutic strategy for prostate cancer has been ineffective clinically. However, we show here that membranous HER3 protein is commonly highly expressed in lethal prostate cancer, associating with reduced time to castration resistance (CR) and survival. Multiplex immunofluorescence indicated that the HER3 ligand NRG1 is detectable primarily in tumor-infiltrating myelomonocytic cells in human prostate cancer; this observation was confirmed using single-cell RNA sequencing of human prostate cancer biopsies and murine transgenic prostate cancer models. In castration-resistant prostate cancer (CRPC) patient-derived xenograft organoids with high HER3 expression as well as mouse prostate cancer organoids, recombinant NRG1 enhanced proliferation and survival. Supernatant from murine bone marrow-derived macrophages and myeloid-derived suppressor cells promoted murine prostate cancer organoid growth in vitro, which could be reversed by a neutralizing anti-NRG1 antibody and ERBB inhibition. Targeting HER3, especially with the HER3-directed antibody-drug conjugate U3-1402, exhibited antitumor activity against HER3-expressing prostate cancer. Overall, these data indicate that HER3 is commonly overexpressed in lethal prostate cancer and can be activated by NRG1 secreted by myelomonocytic cells in the tumor microenvironment, supporting HER3-targeted therapeutic strategies for treating HER3-expressing advanced CRPC. SIGNIFICANCE: HER3 is an actionable target in prostate cancer, especially with anti-HER3 immunoconjugates, and targeting HER3 warrants clinical evaluation in prospective trials.

Signaling Pathways That Control Apoptosis in Prostate Cancer

Prostate cancer is the second most common malignancy and the fifth leading cancer-caused death in men worldwide. Therapies that target the androgen receptor axis induce apoptosis in normal prostates and provide temporary relief for advanced disease, yet prostate cancer that acquired androgen independence (so called castration-resistant prostate cancer, CRPC) invariably progresses to lethal disease. There is accumulating evidence that androgen receptor signaling do not regulate apoptosis and proliferation in prostate epithelial cells in a cell-autonomous fashion. Instead, androgen receptor activation in stroma compartments induces expression of unknown paracrine factors that maintain homeostasis of the prostate epithelium. This paradigm calls for new studies to identify paracrine factors and signaling pathways that control the survival of normal epithelial cells and to determine which apoptosis regulatory molecules are targeted by these pathways. This review summarizes the recent progress in understanding the mechanism of apoptosis induced by androgen ablation in prostate epithelial cells with emphasis on the roles of BCL-2 family proteins and "druggable" signaling pathways that control these proteins. A summary of the clinical trials of inhibitors of anti-apoptotic signaling pathways is also provided. Evidently, better knowledge of the apoptosis regulation in prostate epithelial cells is needed to understand mechanisms of androgen-independence and implement life-extending therapies for CRPC.

EGFR/FOXO3A/LXR-α Axis Promotes Prostate Cancer Proliferation and Metastasis and Dual-Targeting LXR-α/EGFR Shows Synthetic Lethality

Prostate cancer is the second leading cause of cancer-related death in men. Early prostate cancer has a high 5-year survival rate. However, the five-year survival rate is low in progressive prostate cancer, which manifests as bone metastasis. The EGF receptor overexpression increases during disease progression and in the development of castration-resistant disease, and may be a potential therapeutic target. Liver X receptors (LXRs) are ligand-dependent nuclear receptor transcription factors and consist of two subtypes, LXR-α and LXR-β, which can inhibit tumor growth in various cancer cells. We revealed that LXR-α, but not LXR-β, was reduced in prostate cancer tissues compared with adjacent normal tissues. LXRs' agonist GW3965 enhanced the inhibitory action of LXR-α on the proliferation and metastasis of prostate cancer cells. Furthermore, our results support the notion that LXR-α is regulated by the EGFR/AKT/FOXO3A pathway. As an EGFR inhibitor, Afatinib could weaken AKT activation and increase the expression level of FOXO3A in prostate cancer. In addition, we indicated that the combination of Afatinib and GW3965 simultaneously increased and activated LXR-α, which led to an increase of tumor suppressors, and eventually inhibited tumor progression. Therefore, the combination of EGFR inhibitor and LXRs agonist may become a potential treatment strategy for prostate cancer, especially metastatic prostate cancer.

Deciphering role of FGFR signalling pathway in pancreatic cancer

Recently, fibroblast growth factors are identified to play a vital role in the development and progression of human pancreatic cancer. FGF pathway is critical involved in numerous cellular processes through regulation of its downstream targets, including proliferation, apoptosis, migration, invasion, angiogenesis and metastasis. In this review article, we describe recent advances of FGFR signalling pathway in pancreatic carcinogenesis and progression. Moreover, we highlight the available chemical inhibitors of FGFR pathway for potential treatment of pancreatic cancer. Furthermore, we discuss whether targeting FGFR pathway is a novel therapeutic strategy for pancreatic cancer clinical management.

ErbB-2 signaling in advanced prostate cancer progression and potential therapy

Currently, prostate cancer (PCa) remains the most commonly diagnosed solid tumor and the second leading cause of cancer-related deaths in US men. Most of these deaths are attributed to the development of castration-resistant (CR) PCa. ErbB-2 and ErbB family members have been demonstrated to contribute to the progression of this lethal disease. In this review, we focus on updating the role of ErbB-2 in advanced PCa progression and its regulation, including its regulation via ligand activation, miRNAs and protein phosphorylation. We also discuss its downstream signaling pathways, including AKT, ERK1/2 and STATs, involved in advanced PCa progression. Additionally, we evaluate the potential of ErbB-2, focusing on its protein hyper-phosphorylation status, as a biomarker for aggressive PCa as well as the effectiveness of ErbB-2 as a target for the treatment of CR PCa via a multitude of approaches, including orally available inhibitors, intratumoral expression of cPAcP, vaccination and immunotherapy.

Induction of entosis in prostate cancer cells by nintedanib and its therapeutic implications

Entosis is a homogeneous cell-in-cell phenomenon and a non-apoptotic cell death process. Tyrosine kinase inhibitors have been used in the treatment of prostate cancer and have already demonstrated efficacy in a clinical setting. The present study investigated the role of entosis in prostate cancer treated with the tyrosine kinase inhibitor nintedanib. Prostate cancer cells were treated with nintedanib in vitro and entosis was observed. Mice xenografts were created to evaluate whether nintedanib is able to induce entosis in vivo. The reverse transcription-quantitative polymerase chain reaction, western blotting and immunofluorescence were performed to investigate whether the entosis pathway is induced by nintedanib. It was also investigated whether entosis can contribute to cell survival and progression under nintedanib stress, and nintedanib was revealed to enhance prostate cancer cell entosis. Nintedanib-induced entosis in prostate cancer cells occurred through phosphoinositide 3-kinase/cell division cycle 42 (CDC42) inhibition, followed by the upregulation of epithelial (E-)cadherin and components of the Rho kinase (ROCK) signaling pathway. In addition, nintedanib-resistant cells exhibiting entosis had a higher invasive ability. In addition, in vivo treatment of mice xenografts with nintedanib also increased the expression of E-cadherin and components of the ROCK signaling pathway. Nintedanib can promote entosis during prostate cancer treatment by modulating the CDC42 pathway. Furthermore, prostate cancer cells acquired nintedanib resistance and survived by activating entosis.

Afatinib

Afatinib (BIBW 2992, US: Gilotrif^TM, other countries: Giotrif©) is an irreversible blocker of the ErbB family, acting at the tyrosine kinases of these proteins. In 2013, it was approved by the FDA and the EMA for the treatment of adults with advanced, EGFR mutation-positive non-small-cell lung cancer. Further investigations for the treatment of many other tumors with afatinib, e.g., HNSCC and breast cancer, are ongoing.

Discovering drugs to overcome chemoresistance in ovarian cancers based on the cancer genome atlas tumor transcriptome profile

Ovarian cancer accounts for the highest mortality among gynecologic cancers, mainly due to intrinsic or acquired chemoresistance. While mechanistic-based methods have been used to identify compounds that can overcome chemoresistance, an effective comprehensive drug screening has yet to be developed. We applied a transcriptome based drug sensitivity prediction method, to the Cancer Genome Atlas (TCGA) ovarian cancer dataset to impute patient tumor response to over 100 different drugs. By stratifying patients based on their predicted response to standard of care (SOC) chemotherapy, we identified drugs that are likely more sensitive in SOC resistant ovarian tumors. Five drugs (ABT-888, BIBW2992, gefitinib, AZD6244 and lenalidomide) exhibit higher efficacy in SOC resistant ovarian tumors when multi-platform of transcriptome profiling methods were employed. Additional in vitro and clinical sample validations were carried out and verified the effectiveness of these agents. Our candidate drugs hold great potential to improve clinical outcome of chemoresistant ovarian cancer.

Nintedanib antiangiogenic inhibitor effectiveness in delaying adenocarcinoma progression in Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP)

Background

In recent times, anti-cancer treatments have focused on Fibroblast Growth Factor (FGF) and Vascular-Endothelial Growth Factor (VEGF) pathway inhibitors so as to target tumor angiogenesis and cellular proliferation. One such drug is Nintedanib; the present study evaluated the effectiveness of Nintedanib treatment against in vitro proliferation of human prostate cancer (PCa) cell lines, and growth and progression of different grades of PCa lesions in pre-clinical PCa transgenic adenocarcinoma for the mouse prostate (TRAMP) model.

Methods

Both androgen-independent (LNCaP) and androgen-dependent (PC3) PCa cell lines were treated with a range of Nintedanib doses for 72 h, and effect on cell growth and expression of angiogenesis associated VEGF receptors was analyzed. In pre-clinical efficacy evaluation, male TRAMP mice starting at 8 and 12 weeks of age were orally-fed with vehicle control (10% Tween 20) or Nintedanib (10 mg/Kg/day in vehicle control) for 4 weeks, and sacrificed immediately after 4 weeks of drug treatment or sacrificed 6–10 weeks after stopping drug treatments. At the end of treatment schedule, mice were sacrificed and ventral lobe of prostate was excised along with essential metabolic organ liver, and subjected to histopathological and extensive molecular evaluations.

Results

The total cell number decreased by 56–80% in LNCaP and 45–93% in PC3 cells after 72 h of Nintedanib treatment at 2.5–25 μM concentrations. In pre-clinical TRAMP studies, Nintedanib led to a delay in tumor progression in all treatment groups; the effect was more pronounced when treatment was given at the beginning of the glandular lesion development and continued till study end. A decreased microvessel density and VEGF immunolocalization was observed, besides decreased expression of Androgen Receptor (AR), VEGFR-1 and FGFR-3 in some of the treated groups. No changes were observed in the histological liver analysis.

Conclusions

Nintedanib treatment was able to significantly decrease the growth of PCa cell lines and also delay growth and progression of PCa lesions to higher grades of malignancy (without inducing any hepatotoxic effects) in TRAMP mice. Furthermore, it was observed that Nintedanib intervention is more effective when administered during the early stages of neoplastic development, although the drug is capable of reducing cell proliferation even after treatment interruption.

GABABR-Induced EGFR Transactivation Promotes Migration of Human Prostate Cancer Cells

G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs) act in concert to regulate cell growth, proliferation, survival, and migration. Metabotropic GABA_B receptor (GABA_BR) is the GPCR for the main inhibitory neurotransmitter GABA in the central nervous system. Increased expression of GABA_BR has been detected in human cancer tissues and cancer cell lines, but the role of GABA_BR in these cells is controversial and the underlying mechanism remains poorly understood. Here, we investigated whether GABA_BR hijacks RTK signaling to modulate the fates of human prostate cancer cells. RTK array analysis revealed that the GABA_BR-specific agonist baclofen selectively induced the transactivation of EGFR in PC-3 cells. EGFR transactivation resulted in the activation of ERK1/2 by a mechanism that is dependent on G_i/o protein and that requires matrix metalloproteinase-mediated proligand shedding. Positive allosteric modulators (PAMs) of GABA_BR, such as CGP7930, rac-BHFF, and GS39783, can function as PAM agonists to induce EGFR transactivation and subsequent ERK1/2 activation. Moreover, both baclofen and CGP7930 promoted cell migration and invasion through EGFR signaling. In summary, our observations demonstrated that GABA_BR transactivated EGFR in a ligand-dependent mechanism to promote prostate cancer cell migration and invasion, thus providing new insights into developing a novel strategy for prostate cancer treatment by targeting neurotransmitter signaling.

Benefits of Multifaceted Chemopreventives in the Suppression of the Oral Squamous Cell Carcinoma (OSCC) Tumorigenic Phenotype

Over one third of patients who have undergone oral squamous cell carcinoma (OSCC) surgical resections develop life-threatening and often untreatable recurrences. A variety of drugs, intended for management of recurrent or disseminated cancers, were designed to exploit cancer cells' reliance upon overexpressed receptors and gratuitous signaling. Despite their conceptual promise, clinical trials showed these agents lacked efficacy and were often toxic. These findings are consistent with evasion of pathway-targeted treatments via extensive signaling redundancies and compensatory mechanisms common to cancers. Optimal secondary OSCC chemoprevention requires long-term efficacy with multifaceted, nontoxic agents. Accordingly, this study evaluated the abilities of three complementary chemopreventives, that is, the vitamin A derivative fenretinide (4-HPR, induces apoptosis and differentiation, inhibits signaling proteins, and invasion), the estrogen metabolite 2-methoxyestradiol (2-ME, apoptosis-inducing, antiangiogenic), and the humanized mAb to the IL6R receptor tocilizumab (TOC, reduces IL6 signaling) to suppress OSCC gratuitous signaling and tumorigenesis. Modeling studies demonstrated 4-HPR's high-affinity binding at STAT3's dimerization site and c-Abl and c-Src ATP-binding kinase sites. Although individual agents suppressed cancer-promoting pathways including STAT3 phosphorylation, STAT3-DNA binding, and production of the trans-signaling enabling sIL6R, maximal chemopreventive effects were observed with agent combinations. OSCC tumor xenograft studies showed that locally delivered TOC, TOC+4-HPR, and TOC+4-HPR+2-ME treatments all prevented significant tumor growth. Notably, the TOC+4-HPR+2-ME treatment resulted in the smallest overall increase in tumor volume. The selected agents use diverse mechanisms to disrupt tumorigenesis at multiple venues, that is, intracellular, tumor cell-ECM, and tumor microenvironment; beneficial qualities for secondary chemopreventives. Cancer Prev Res; 10(1); 76-88. ©2016 AACR.

Risk of selected gastrointestinal and hepatic toxicities in cancer patients treated with nintedanib: a meta-analysis

Background: A meta-analysis of the risk of selected gastrointestinal and hepatic toxicities associated with nintedanib has been conducted. Methods: Randomized Phase II/III trials of cancer patients on nintedanib; describing events of diarrhea, vomiting, elevated ALT and elevated AST constituted the eligible studies. Results: The odds ratio for high-grade diarrhea was 3.76 (95% CI: 1.42–9.96; p = 0.008); high-grade vomiting: 1.38 (95% CI: 0.76–2.51; p = 0.28); high-grade elevated ALT: 4.36 (95% CI: 2.14–8.85; p < 0.0001); high-grade elevated AST: 6.96 (95% CI: 4.09–11.85; p < 0.00001). Conclusion: Nintedanib-based regimens are associated with a higher risk of high-grade diarrhea, elevated ALT and elevated AST. Moreover, there is a proportional relationship between nintedanib dose and the risk of elevated transaminases.

Afatinib reverses multidrug resistance in ovarian cancer via dually inhibiting ATP binding cassette subfamily B member 1

ABCB1-mediated multidrug resistance (MDR) remains a major obstacle to successful chemotherapy in ovarian cancer. Herein, afatinib at nontoxic concentrations significantly reversed ABCB1-mediated MDR in ovarian cancer cells in vitro (p < 0.05). Combining paclitaxel and afatinib caused tumor regressions and tumor necrosis in A2780T xenografts in vivo. More interestingly, unlike reversible TKIs, afatinib had a distinctive dual-mode action. Afatinib not only inhibited the efflux function of ABCB1, but also attenuated its expression transcriptionally via down-regulation of PI3K/AKT and MAPK/p38-dependent activation of NF-κB. Furthermore, apart from a substrate binding domain, afatinib could also bind to an ATP binding domain of ABCB1 through forming hydrogen bonds with Gly533, Gly534, Lys536 and Ala560 sites. Importantly, mutations in these four binding sites of ABCB1 and the tyrosine kinase domain of EGFR were not correlated with the reversal activity of afatinib on MDR. Given that afatinib is a clinically approved drug, our results suggest combining afatinib with chemotherapeutic drugs in ovarian cancer. This study can facilitate the rediscovery of superior MDR reversal agents from molecular targeted drugs to provide a more effective and safer way of resensitizing MDR.

A Phase I dose-escalation study of afatinib combined with nintedanib in patients with advanced solid tumors

AIMS

To evaluate the safety and maximum tolerated dose (MTD) of afatinib combined with nintedanib.

MATERIALS & METHODS

Patients received afatinib 10-20 mg daily plus nintedanib 150-200 mg twice daily (28-day cycle). Dose escalation followed a 3+3 design.

RESULTS

Patients received afatinib/nintedanib: 10/150 mg (n = 11); 10/200 mg (n = 13; MTD); 20/200 mg (n = 4). Four patients had dose-limiting toxicities (all grade 3): increased alanine aminotransferase (afatinib/nintedanib: 10/150 mg), diarrhea (10/200 mg), dehydration (20/200 mg), diarrhea with elevated liver enzymes (20/200 mg). Frequent treatment-related adverse events were diarrhea, nausea, anorexia, fatigue and vomiting. In total, 14 patients (46.2%) had objective responses at the MTD.

CONCLUSION

The MTD, afatinib 10 mg daily plus nintedanib 200 mg twice daily, had a manageable safety profile, but was considered subtherapeutic for Phase II evaluation.

Profile of nintedanib in the treatment of solid tumors: the evidence to date

Angiogenesis is an essential process for tumor growth and metastasis, and remains a promising therapeutic target process in cancer treatment for several cancer types. Bevacizumab, a monoclonal antibody that targets vascular endothelial growth factor (VEGF), was the first antiangiogenic agent approved for cancer therapy. Novel antiangiogenic agents, such as sunitinib, sorafenib, pazopanib, or vandetanib that target additional proangiogenic signaling pathways beyond VEGF, have also been approved for the treatment of various malignant diseases. While most of these agents are approved in combination with cytotoxic chemotherapy for indications including metastatic colorectal cancer, non-small-cell lung cancer, breast cancer, renal cell carcinoma (RCC), and gastric cancer, some are used as approved monotherapy for advanced RCC, hepatocellular carcinoma and medullary thyroid cancer. Major challenges to the success of antiangiogenic therapy include associated toxicity risks, limitation of efficacy through the possible development of resistance and induction or promotion of metastatic progression. Nintedanib (formally known as BIBF 1120) is a triple angiokinase inhibitor of VEGF, fibroblast growth factor, platelet-derived growth factor signaling with lesser activity against RET, Flt-3, and Src. Through this unique targeting profile nintedanib has demonstrated significant antitumor activity in several tumor types in preclinical studies. Nintedanib has also shown promising clinical efficacy in combination with docetaxel and has been approved for treating patients with locally advanced and metastatic non-small-cell lung cancer in Europe. Nintedanib has also been found to be clinically promising in terms of efficacy and safety in several other solid tumors including ovarian cancer (Phase III), RCC (Phase II), and prostate cancer (Phase II). This review article provides a comprehensive summary of the preclinical and clinical efficacy of nintedanib in the treatment of solid tumors.

Persistent androgen receptor addiction in castration-resistant prostate cancer

It is now understood that persistent activation of the androgen receptor (AR) signaling pathway often underlies the development of castration-resistant prostate cancer (CRPC). This realization led to renewed interest in targeting the AR and ultimately to the development of the potent next-generation AR-directed agents abiraterone and enzalutamide. While these drugs prolong survival in men with CRPC, they are unfortunately not curative. Perhaps not surprisingly, evidence points to persistent AR signaling as one of the key drivers by which resistances to these agents develops. In this context, activation of the AR signaling program can occur through a number of molecular adaptations, including alterations leading to persistent canonical AR signaling (e.g., AR amplification/overexpression, elucidations/concentration of intratumoral androgens), activation of the AR program via feedback pathways (e.g., AKT/mTOR/Pi3K, HER2/Neu), and activation of the AR program via mutation or substitution (e.g., AR ligand binding domain mutation; AR splice variants; glucocorticoid receptor signaling). This review will provide an overview of the more clinical relevant (i.e., druggable) pathways that have been implicated in the emergence of drug resistance in men with CRPC and highlight some of the ongoing efforts towards developing therapeutics to impair these mechanisms.

Phase I study of afatinib combined with nintedanib in patients with advanced solid tumours

Background:

This Phase I study evaluated continuous- and intermittent-dosing (every other week) of afatinib plus nintedanib in patients with advanced solid tumours.

Methods:

In the dose-escalation phase (n=45), maximum tolerated doses (MTDs) were determined for continuous/intermittent afatinib 10, 20, 30 or 40 mg once daily plus continuous nintedanib 150 or 200 mg twice daily. Secondary objectives included safety and efficacy. Clinical activity of continuous afatinib plus nintedanib at the MTD was further evaluated in an expansion phase (n=25).

Results:

The most frequent dose-limiting toxicities were diarrhoea (11%) and transaminase elevations (7%). Maximum tolerated doses were afatinib 30 mg continuously plus nintedanib 150 mg, and afatinib 40 mg intermittently plus nintedanib 150 mg. Treatment-related adverse events (mostly Grade ⩽3) included diarrhoea (98%), asthenia (64%), nausea (62%) and vomiting (60%). In the dose-escalation phase, two patients had partial responses (PRs) and 27 (60%) had stable disease (SD). In the expansion phase, one complete response and three PRs were observed (all non-small cell lung cancer), with SD in 13 (52%) patients. No pharmacokinetic interactions were observed.

Conclusions:

MTDs of continuous or intermittent afatinib plus nintedanib demonstrated a manageable safety profile with proactive management of diarrhoea. Antitumour activity was observed in patients with solid tumours.

Afatinib: An overview of its clinical development in non-small-cell lung cancer and other tumors

Afatinib is an oral, irreversible, tyrosine kinase inhibitor (TKI) of EGFR, HER2 and HER4. According to phase I studies, the recommended dose of afatinib was 50mg daily. Rash, acne, diarrhea and stomatitis were the most common adverse events. Afatinib failed to demonstrate an improvement in overall survival in unselected heavily pretreated NSCLC patients (Lux-Lung-1). On the contrary, the Lux-Lung-3 and -6 trials met the primary end point, demonstrating a significant increase in terms of PFS with afatinib compared with chemotherapy in the first line treatment of EGFR mutant patients. Moreover, in both studies, afatinib improved overall survival in patients with exon 19 EGFR deletion (31.7 vs 20.7 months; HR: 0.59, p=0.0001). The results of ongoing randomized trials should further clarify the efficacy of afatinib compared with first-generation TKIs in advanced NSCLC, its activity in the adjuvant and neoadjuvant settings, as well as its efficacy in other tumors.

Regulation of vascular endothelial growth factor in prostate cancer

Prostate cancer (PCa) is the most common malignancy affecting men in the western world. Although radical prostatectomy and radiation therapy can successfully treat PCa in the majority of patients, up to ~30% will experience local recurrence or metastatic disease. Prostate carcinogenesis and progression is typically an androgen-dependent process. For this reason, therapies for recurrent PCa target androgen biosynthesis and androgen receptor function. Such androgen deprivation therapies (ADT) are effective initially, but the duration of response is typically ≤24 months. Although ADT and taxane-based chemotherapy have delivered survival benefits, metastatic PCa remains incurable. Therefore, it is essential to establish the cellular and molecular mechanisms that enable localized PCas to invade and disseminate. It has long been accepted that metastases require angiogenesis. In the present review, we examine the essential role for angiogenesis in PCa metastases, and we focus in particular on the current understanding of the regulation of vascular endothelial growth factor (VEGF) in localized and metastatic PCa. We highlight recent advances in understanding the role of VEGF in regulating the interaction of cancer cells with tumor-associated immune cells during the metastatic process of PCa. We summarize the established mechanisms of transcriptional and post-transcriptional regulation of VEGF in PCa cells and outline the molecular insights obtained from preclinical animal models of PCa. Finally, we summarize the current state of anti-angiogenesis therapies for PCa and consider how existing therapies impact VEGF signaling.