Antiangiogenic tyrosine kinase inhibitors in colorectal cancer: is there a path to making them more effective?

A study protocol for an open-label, single-arm, single-center phase I clinical study on tolerability, safety, and efficacy of dalpiciclib combined with apatinib in the treatment of patients with advanced or metastatic sarcoma

INTRODUCTION

The prognosis of patients with advanced or metastatic sarcoma is very poor, and a new strategy for patients who fail systemic treatment is urgently required. Apatinib is a small molecule tyrosine kinase inhibitor of VEGFR-2, which can exert an antitumor effect by blocking downstream PI3K/AKT and VEGFR2/STAT3 signaling pathways of sarcoma. Dysregulation of the cyclin D (CCND)-cyclin-dependent kinase 4/6 (CDK4/6)-retinoblastoma 1 (Rb) pathway is highly prevalent in sarcoma. Thus, blocking VEGFR2 and CDK4/6 may exert a synergistic effect. We hypothesize that a combination of apatinib and dalpiciclib, an oral, highly effective, and selective small molecule CDK4/6 inhibitor, may result in higher antitumor efficacy in patients with refractory sarcoma.

METHODS

In this open-label, single-arm, single-center phase I trial, participants diagnosed with sarcoma who failed standard systemic treatment will be enrolled. Dose escalation will be conducted into three groups according to traditional 3 + 3 principle: dose 1, dalpiciclib 100 mg once daily oral d1-21+ apatinib 250 mg once daily oral d1-28, every 28 days as one cycle; dose 2, dalpiciclib 100 mg d1-21+ apatinib 500 mg d1-28; dose 3, dalpiciclib 150 mg d-21+ apatinib 500 mg d1-28. The primary endpoint is the safety and tolerability of combined treatment. The secondary endpoint is to evaluate the initial efficacy, including objective response rate (ORR), disease control rate (DCR), duration of response (DoR), and progression-free survival (PFS).

DISCUSSION

This trial will provide evidence of the tolerability, safety, and efficacy of dalpiciclib in combination with apatinib in metastatic sarcoma patients who have failed first-line systemic treatment.

OUP accepted manuscript

BACKGROUND

The antiangiogenic tyrosine kinase inhibitor regorafenib provides a survival benefit in patients with previously treated metastatic colorectal cancer (CRC). Antiangiogenic therapy causes hypoxic stress within tumor cells, which activates autophagy as a survival mechanism. The histone deacetylase inhibitor (HDAC) entinostat increases dependence on autophagy through epigenetic mechanisms. Hydroxychloroquine (HCQ) blocks autophagy by blunting lysosomal acidification. We hypothesized that HCQ and entinostat would be tolerable with regorafenib and potentiate the antitumor response.

METHODS

This was a 3+3 phase I trial of HCQ and entinostat with regorafenib in patients with metastatic CRC. The primary objective was safety, and the secondary objective was clinical efficacy.

RESULTS

Twenty patients received study therapy. Six evaluable patients were enrolled at each of the three planned dose levels, one patient at an intermediate dose level, and one additional patient withdrew consent after 4 days to receive treatment closer to home. One dose-limiting toxicity was noted in the study at dose level 2 (grade 3 fatigue). Seven patients discontinued therapy due to related toxicities; rapid weight loss was near universal, with a median weight loss of 4.4 kg (range 1.5-12.2 kg) in the first 2 weeks of treatment. No objective responses were observed.

CONCLUSION

The combination of regorafenib, HCQ, and entinostat was poorly tolerated without evident activity in metastatic CRC.

CLINICALTRIALS.GOV IDENTIFIER

NCT03215264.

Angiogenesis-Related Functions of Wnt Signaling in Colorectal Carcinogenesis

Simple Summary

Angiogenesis belongs to the most clinical characteristics of colorectal cancer (CRC) and is strongly linked to the activation of Wnt/β-catenin signaling. The most prominent factors stimulating constitutive activation of this pathway, and in consequence angiogenesis, are genetic alterations (mainly mutations) concerning APC and the β-catenin encoding gene (CTNNB1), detected in a large majority of CRC patients. Wnt/β-catenin signaling is involved in the basic types of vascularization (sprouting and nonsprouting angiogenesis), vasculogenic mimicry as well as the formation of mosaic vessels. The number of known Wnt/β-catenin signaling components and other pathways interacting with Wnt signaling, regulating angiogenesis, and enabling CRC progression continuously increases. This review summarizes the current knowledge about the role of the Wnt/Fzd/β-catenin signaling pathway in the process of CRC angiogenesis, aiming to improve the understanding of the mechanisms of metastasis as well as improvements in the management of this cancer.

Abstract

Aberrant activation of the Wnt/Fzd/β-catenin signaling pathway is one of the major molecular mechanisms of colorectal cancer (CRC) development and progression. On the other hand, one of the most common clinical CRC characteristics include high levels of angiogenesis, which is a key event in cancer cell dissemination and distant metastasis. The canonical Wnt/β-catenin downstream signaling regulates the most important pro-angiogenic molecules including vascular endothelial growth factor (VEGF) family members, matrix metalloproteinases (MMPs), and chemokines. Furthermore, mutations of the β-catenin gene associated with nuclear localization of the protein have been mainly detected in microsatellite unstable CRC. Elevated nuclear β-catenin increases the expression of many genes involved in tumor angiogenesis. Factors regulating angiogenesis with the participation of Wnt/β-catenin signaling include different groups of biologically active molecules including Wnt pathway components (e.g., Wnt2, DKK, BCL9 proteins), and non-Wnt pathway factors (e.g., chemoattractant cytokines, enzymatic proteins, and bioactive compounds of plants). Several lines of evidence argue for the use of angiogenesis inhibition in the treatment of CRC. In the context of this paper, components of the Wnt pathway are among the most promising targets for CRC therapy. This review summarizes the current knowledge about the role of the Wnt/Fzd/β-catenin signaling pathway in the process of CRC angiogenesis, aiming to improve the understanding of the mechanisms of metastasis as well as improvements in the management of this cancer.

Apatinib: A Review in Advanced Gastric Cancer and Other Advanced Cancers

Apatinib [Aitan^® (brand name in China)], also known as rivoceranib, is a novel, small molecule, selective vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitor and is the second anti-angiogenic drug to be approved in China for the treatment of advanced or metastatic gastric cancer. This article summarizes the pharmacological properties of apatinib and reviews its clinical use in chemotherapy-experienced patients with advanced gastric adenocarcinoma, including gastroesophageal adenocarcinoma (GEA), or with other advanced cancers such as non-small cell lung cancer (NSCLC), breast cancer, gynaecological cancers, hepatocellular carcinoma (HCC), thyroid cancer and sarcomas. As third- or subsequent-line therapy, oral apatinib significantly prolonged median progression-free survival (PFS) and overall survival (OS) compared with placebo and had a manageable safety profile in Chinese patients with advanced or metastatic gastric cancer or GEA participating in randomized, double-blind, multicentre, phase 2 and 3 trials. More limited evidence also supports it use as subsequent-line treatment in Chinese patients with other advanced or metastatic solid tumours, including NSCLC, breast cancer and HCC. Further clinical experience and long-term pharmacovigilance data are required to more definitively establish the efficacy and safety profile of apatinib, including its use in combination with other chemotherapy agents and its role in the management of other types of advanced or metastatic solid tumours. In the meantime, given its convenient administration regimen and the limited treatment options and poor prognosis for patients with advanced or metastatic solid tumours, apatinib is an important, emerging treatment option for adult patients with advanced gastric adenocarcinoma or GEA who have progressed or relapsed after chemotherapy.

The molecular mechanism of ovarian granulosa cell tumors

Over these years, more and more sex cord-stromal tumors have been reported. Granulosa cell tumor (GCT) is a rare tumor in ovaries, accounts for 2% to 5% of ovarian cancers. The main different feature of GCTs from other ovarian cancers is that GCTs can lead to abnormally secreted hormones (estrogen, inhibin and Müllerian inhibiting substance). The GCT is divided into two categories according to the age of patients, namely AGCT (adult granulosa cell tumor) and JGCT (Juvenile granulosa cell tumor). AGCT patients accounts for 95%. Although the pathogenesis is not clear, FOXL2 (Forkhead box L2) mutation was considered as the most critical factor in AGCT development. The current treatment is dominated by surgery. Target therapy remains in the adjuvant therapy stage, such as hormone therapy. During these years, other pathogenic factors were also explored, such as PI3K/AKT (phosphatidylinositol-3-kinase; serine/threonine kinase), TGF-β (Transforming growth factor beta) signaling pathway, Notch signaling pathway, GATA4 and VEGF (vascular endothelial growth factor). These factors and signaling pathway play important roles in GCT cell proliferation, apoptosis, or angiogenesis. The purpose of this review is to summarize the possible pathogenic factors and signaling pathways, which may shed lights on developing potential therapeutic targets for GCT.