Are CXCR4 Antagonists Making a Comeback in Cancer Chemotherapy?
Reporter: Stephen J. Williams, Ph.D.
Biospace News reported that Massachusetts based X4 Pharmaceuticals is using $34B to launch two clinical trials on its CXCR4 inhibitor X4P-001 in refractory clear cell renal cell carcinoma and refractory epithelial ovarian cancer.
The full report is below:
X4 Pharma Uses $37.5 Million to Push Cancer Therapies into Human Trials
December 14, 2015
By Alex Keown, BioSpace.com Breaking News Staff
CAMBRIDGE, Mass. – Massachusetts based X4 Pharmaceuticals is beginning human trials for its oncology program using CXCR4 inhibitors, the Boston Business Journal reported this morning.
After spending years in stealth mode, the company, helmed by former Genzyme executives, is launching two clinical two clinical studies initiating in 2016 in refractory clear cell renal cell carcinoma and refractory epithelial ovarian cancer with its lead drug candidate, X4P-001.
The company’s pipeline is based on drug compounds that originate from a portfolio of oral CXCR4 inhibitors exclusively licensed from Sanofi (SNY), X4 said in a statement. Inhibition of CXCR4, a receptor over-expressed in many cancers, is designed to block non-cancerous immuno-suppressive and pro-angiogenic cells from populating the tumor, thereby disrupting the cancer microenvironment and restoring normal immune surveillance functions. The novel mechanism of CXCR4 inhibition increases the ability of T-Cells to track and destroy cancer. X4 is leveraging its CXCR4 research against past experience working with Genzyme’s plerixafor, which is also a CXCR4 blocker.
In an interview with the Journal, Paula Ragan, X4’s chief executive officer, said the CXCR4 protein “acts as a beacon to attract cells to surround a tumor, effectively hiding the tumor from the body’s T cells that would otherwise destroy them.” Developing a therapy to block the protein will prevent the tumors from hiding and allow it to be treated.
Ragan said the Phase Ia trial for X4P-001 will test safety and dosage in a small trial of about 20 people, the Journal reported. If all goes well the company would start a Phase 2a trial by the end of 2016 in around 50 or 60 patients, the Journal said.
In September, Ragan said a CXCR4 antagonist could potentially be paired with promising oncology drugs like Merck & Co. (MRK)’s Keytruda, or Bristol-Myers Squibb (BMY)’s Opdivo. Keytruda has been shown to be effective in treating patients with three types of cancer, melanoma, lung cancer and mesothelioma. Opdivo is a treatment of patients with metastatic squamous non-small cell lung cancer (NSCLC) with progression on or after platinum-based chemotherapy.
The cytokines and cytokine receptors have been investigated before for their utility as a chemotherapeutic target as they are highly expressed on tumors and promote metastasis. The general idea was that tumor cells secrete cytokines which promote their growth and metastases and attract immune cells which also secrete growth-promoting cytokines. Many tumor types have shown increased expression of these cytokines and cytokine receptors. However only some development efforts have shown promise, there have been no approved drugs in this class. As written in a previous post (Tumor Associated Macrophages: The Double-Edged Sword Resolved?), there could be many biological reasons for this, as well as difficulties in interpreting preclinical results in immunocompromised mice.
CXCR4: from the review by Ori Wald, Oz M. Shapira, Uzi Izha
Source: Wald O, Shapira OM, Izhar U. CXCR4/CXCL12 Axis in Non Small Cell Lung Cancer (NSCLC) Pathologic Roles and Therapeutic Potential. Theranostics 2013; 3(1):26-33. doi:10.7150/thno.4922. Available from http://www.thno.org/v03p0026.htm
Chemokines, a family of 48 chemotactic cytokines interact with their 7 transmembrane G-protein-coupled receptors to guide immune cell trafficking in the body under both physiologic and pathologic conditions (20, 21). Tumor cells, which express a relatively restricted repertoire of chemokine and chemokine receptors, utilize and manipulate the chemokine system in a manner that benefits both local tumor growth and distant dissemination (20, 22, 23). In the tumor microenvironment autocrine and paracrine chamokine/chemokine receptor loops interact to promote tumor cell survival and growth, and also to enhance tumor neo-angiogenesis (20, 22, 23). At distant sites, it is the tissue-produced chemokine which guide/attracts the metastasis of chemokine receptor expressing tumor cells (20).
Among the 19 chemokine receptors, CXCR4 is the receptor most widely expressed by malignant tumors and whose role in tumor biology is most thoroughly studied (20). The chemokine CXCL12 is the sole ligand of CXCR4 and the majority of research that focus on the role of CXCR4 in cancer relates to this chemokine/chemokine receptor pair (24, 25). Nevertheless, in 2006 another receptor for CXCL12 was identified and named CXCR7 (26). CXCR7 is expressed during embriogenesis, angiogenesis and in various malignant tissues including NSCLC. CXCR7 is thought to act in part as a scavenger of CXCL12 however additional functions for this receptor have also been reported (26–28). In distinct form CXCR4, CXCR7 binds not only CXCL12 but also the chemokine CXCL11 (26, 27). Moreover, the signaling cascades that are generated upon binding of CXCL12 to CXCR4 or CXCR7 vary at least partly, depending on which of the receptors is engaged (26, 27). This review focuses mainly on data collected regarding the expression and function of CXCR4 in NSCLC, nevertheless it is important to keep in mind that whenever CXCL12 is mentioned the effects related to its expression may be attributed in part to CXCR7 expression and function.
Relative to normal cells in the tumor’s tissue of origin, malignant cells often over express CXCR4, this phenotype can be induced by multiple oncogenic alternations and appears to promote tumor cell survival, proliferation, invasion and metastasis (20, 29–35).
Potential roles for CXCR4/CXCL12 in NSCLC. NSCLC tumor cells express CXCR4 and produce CXCL12. Tumor expressed CXCR4 guides metastatic spread to sights such as the brain, bone marrow and liver that express high levels of CXCL12. In addition, CXCR4/CXCL12 interactions act locally in autocrine and paracrine manners to enhance primary tumor growth and to alter its inflammatory milieu. Tumor and tumor microenvironment secreted CXCL12 enhance tumor cell survival and growth and may also guide trafficking of immune and bone marrow derived cells into the tumor microenvironment. Furthermore, alternations in the tumor microenvironment result from the stimulation of tumor cells with CXCL12 that in turn enhance the production of additional chemokines such as the pro-inflammatory and pro-proliferative chemokine CCL20) pro-angiogenic and pro-proliferative chemokine (CXCL1 – IL-8). Figure from Wald O, Shapira OM, Izhar U. CXCR4/CXCL12 Axis in Non Small Cell Lung Cancer (NSCLC) Pathologic Roles and Therapeutic Potential. Theranostics 2013; 3(1):26-33. doi:10.7150/thno.4922. Available from http://www.thno.org/v03p0026.htm
For further reference on CXCR4 and development of CXCR4 inhibitors please see the following references:
- Peled A, Wald O, Burger J. Development of novel CXCR4-based therapeutics. Expert Opin Investig Drugs. 2012Mar;21(3):341-53
- Balkwill FR. The chemokine system and cancer. J Pathol. 2012Jan;226(2):148-57
- Burger JA, Kipps TJ. CXCR4: a key receptor in the crosstalk between tumor cells and their microenvironment. Blood. 2006Mar1;107(5):1761-7
- Burger JA, Peled A. CXCR4 antagonists: targeting the microenvironment in leukemia and other cancers. Leukemia. 2009Jan;23(1):43-52
- Otsuka S, Bebb G. The CXCR4/SDF-1 chemokine receptor axis: a new target therapeutic for non-small cell lung cancer. J Thorac Oncol. 2008Dec;3(12):1379-83
Current CXCR4 inhibitors in development
Figure. Structures of Representative Small Molecule CXCR4 Antagonists and CXCL12 Inhibitors. From JJ Zariek et al. Fragment-Based Optimization of Small Molecule CXCL12 Inhibitors for Antagonizing the CXCL12/CXCR4 Interaction. Curr Top Med Chem. 2012; 12(24): 2727–2740.
A Phase 1 Trial of LY2510924, a CXCR4 Peptide Antagonist, in Patients with Advanced Cancer
This manuscript reports the results of a phase I study designed to evaluate the safety and tolerability of the C-X-C motif receptor 4 (CXCR4) inhibitor LY2510924 in patients with advanced cancer. LY2510924 is a peptide antagonist, which blocks stromal cell-derived factor-1 (SDF-1) from CXCR4 binding. CXCR4 is often overexpressed in many cancers and involved in the metastasis of solid tumors. LY2510924 was tolerated with mostly Grade 1/2 adverse events, revealed favorable pharmacokinetics, and demonstrated evidence of target engagement as indicated by dose dependent increases in CD34+ cells.
The purpose of this study is to determine 1) the safety and tolerability of multiple intravenous doses of anti-CXCR4 (BMS-936564) as monotherapy and as combination, and 2) the maximum tolerated dose (MTD) of BMS-936564 in combination with Lenalidomide/Dexamethasone or Bortezomib/Dexamethasone in subjects with relapsed or refractory multiple myeloma.
Novel CXCR4 Antagonist BL-8040 Enters Clinical Testing for CML – See more at: http://www.cancernetwork.com/chronic-myeloid-leukemia/novel-cxcr4-antagonist-enters-clinical-testing-cml#sthash.RoXCC5W6.dpuf
Other posts on this Open Access Journal on CXCR4 and Chemokines in Cancer Include
Assessing effects of antimetastatic treatment
Understanding the Stem Cell Niche: A Webinar by The Scientist
Protein regulator of HIV replication
Immunotherapy in Cancer: A Series of Twelve Articles in the Frontier of Oncology by Larry H Bernstein, MD, FCAP
Humanized Mice May Revolutionize Cancer Drug Discovery
Tumor Associated Macrophages: The Double-Edged Sword Resolved?
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