therapies for metastatic melanoma, the lead target of VMT01 –
Coralville, IA, April 13, 2021 – Viewpoint Molecular Targeting, Inc. (“Viewpoint” or the “Company”), a radiopharmaceutical company developing precision lead-212-based α-particle oncology therapeutics and complementary diagnostic imaging agents, today announced positive preclinical results from a study investigating the potential of the melanocortin 1 receptor (MC1R) for targeted drug delivery for the treatment of metastatic melanoma. Results were presented at the American Association for Cancer Research (AACR) Annual Meeting, being held virtually from April 10 – 15, 2021.
MC1R, a G protein-coupled receptor, has been investigated as a potential target for drug delivery (e.g., peptide receptor radionuclide therapies, peptide-drug conjugates, etc.) to metastatic melanoma cells, as it is overexpressed in melanomas but largely absent in normal tissues. The results from this study indicate that MC1R-targeted therapies, such as peptide receptor radionuclide therapies (PRRT), are a promising alternative to current therapies for metastatic melanoma.
Michael K. Schultz, PhD, Chief Science Officer of Viewpoint commented, “We are very pleased with the results of this preclinical study which demonstrated the viability of leveraging MC1R to specifically target metastatic melanoma, the target for our VMT01 program. Its overexpression on metastatic melanoma cells and absence from normal cells may provide a unique opportunity to deliver radioactive payloads to the tumor while reducing off-target toxicity. Additionally, these results give us confidence in our specialized MC1R targeting peptide as we prepare to launch our Phase 1 imaging study of VMT01. The upcoming study being conducted at the Mayo Clinic will evaluate the ability of VMT01 to identify MC1R positive metastatic melanoma tumors and prepare us for a Phase 1 therapy study for the treatment of metastatic melanoma.”
The abstract titled, Assessing Melanocortin 1 receptor as a target for metastatic melanoma drug delivery, was presented by Viewpoint Biomedical Engineer, Brenna Marks in the Experimental and Molecular Therapeutics session on Saturday, April 10.
Bmax and MC1Rs per cell in five human melanoma cell lines (TXM13, TXM40, Sk-Mel-28, A375, and A2058) were calculated from saturation binding assays using synthetic MC1R ligand [125I]Nle-D-Phe-α-MSH (125I-NDP-α-MSH). An immunohistochemistry (IHC) staining protocol was developed using paraffin-embedded xenografts of TXM13, TXM40, Sk-Mel-28, A375, and A2058 human melanoma cells. IHC staining of MC1R was performed using human melanoma biopsy samples of stage III and IV metastatic melanoma. MC1R-IHC was also performed on Caucasian North American normal tissue specimens including skin, muscle, pituitary gland, adrenal gland, cerebellum, and testis.
125I-NDP-α-MSH binding assay results revealed positive staining in all melanoma cell lines, with the densities up to approximately 3000 receptors/cell in TXM13. The IHC staining also demonstrated positive immunoreactivity against MC1R in stage III and IV human metastatic melanoma biopsy samples. Heterogenous expression of MC1R was found within the biopsy samples and among tumor biopsy samples, and the staining intensity fell within the range of the melanoma cancer cell line xenografts. Conversely, negative IHC staining of MC1R was found in normal tissue specimens, indicating that the expression of MC1R in normal tissues is largely absent. This study establishes an MC1R-IHC staining protocol optimized for clinical applications, and these data demonstrate high expression of MC1R in human melanoma biopsy samples as well as in melanoma cancer cell lines.
VMT01 is specialized peptide designed to target the melanocortin 1 receptor (MC1R) on tumor cells. VMT01 is currently being evaluated in a Phase 1 imaging study being conducted at the Mayo Clinic. Provisional results for the VMT01 imaging study are targeted for Q4 2021. Following the results of the imaging trial, the Company plans to initiate a Phase 1/2a therapy study of VMT01 for the treatment of metastatic melanoma.
About the American Association for Cancer Research (AACR) Annual Meeting
The AACR Annual Meeting program covers the latest discoveries across the spectrum of cancer research—from population science and prevention; to cancer biology, translational, and clinical studies; to survivorship and advocacy—and highlights the work of the best minds in research and medicine from institutions all over the world.
Viewpoint Molecular Targeting is a radiopharmaceutical company developing precision oncology therapeutics and complementary diagnostic imaging agents. The Company’s leading alpha-particle radiotherapies are designed to deliver powerful alpha radiation specifically to cancer cells utilizing specialized targeting peptides. Viewpoint is also developing complementary imaging diagnostics that utilize the same targeting peptide which provide the opportunity to personalize treatment and optimize patient outcomes. This “theranostic” approach enables the ability to see the specific tumor and then treat it to potentially improve efficacy and minimize toxicity associated with many other types of cancer treatments.br />
The Company’s melanoma (VMT01) and neuroendocrine tumor (VMT-𝛼-NET) programs are entering Phase 1 imaging studies, to be followed by Phase 1/2a therapy trials for the treatment of metastatic melanoma and neuroendocrine tumors at two leading academic institutions. For more information, please visit the Company’s website viewpointmt.com.
Chief Executive Officer
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