Personal Genome Diagnostics (PGDx) highlighted its patent-pending microsatellite instability (MSI) testing technology following the U.S. Food and Drug Administration's (FDA) accelerated approval of Merck's immuno-oncology agent Keytruda (pembrolizumab) for children and adults whose advanced solid tumors are marked by MSI. This is the first approval of a cancer drug based on the genetic make-up of the tumor rather than its location in the body. Patients will likely be tested for MSI status before receiving Keytruda under the expanded indication.
Tumors that display MSI have lost the ability to repair errors in their DNA as a result of a condition known as mismatch repair deficiency (MMR). Researchers from The Johns Hopkins University, PGDx and other institutions have shown that tumors displaying MMR deficiency and MSI are more susceptible to successful treatment with Keytruda and other immuno-oncology drugs. MSI tumors have been identified in colorectal, endometrial, gastric and other types of cancer.
"This landmark FDA approval codifies the need to determine whether cancer patients potentially eligible for immuno-oncology therapy have microsatellite instability present in their tumors," Doug Ward, CEO of PGDx said. "It is particularly fitting that the approval involves MSI, a genomic condition whose relevance to cancer therapy was first uncovered by researchers at Johns Hopkins, with assistance from researchers at PGDx. We were thrilled to license rights to the patent-pending MSI measurement technology for immuno-oncology applications developed at Johns Hopkins, and are proud to be the first to offer it in both tissue and liquid biopsy formats. PGDx is also planning to submit a tissue-based MSI assay for FDA review later this year."
PGDx's MSI testing is incorporated in the company's tissue-based CancerSELECT 125 pan cancer genomic profiling assay and its non-invasive PlasmaSELECT 64 pan cancer assay that analyzes circulating tumor DNA in patient plasma. The company also recently received grant funding from the National Cancer Institute to advance liquid biopsy tests for determining a related biomarker known as tumor mutational burden.