Tuesday, May 23, 2017

Landmark FDA Approval Based on Tumor Gene, Not Tissue Type (Mismatch Repair, Keytruda)

In a landmark FDA approval, Keytruda has been approved based on expression of a mismatch repair gene, rather than on a tissue type such as colon cancer or lung cancer.    For additional coverage, see MedCityNews, here.  FDA press release here.  Reuters here, MedPageToday here.   Forbes here.  Genomeweb here.

Four weeks ago, this blog emphasized the growing buzz around total mutational burden, or TMB, which is often triggered by defective DNA repair in cancers (here).

In February 2017, Genomeweb reported that Personal Genome Diagnostics (PGDx) in Baltimore had landed an NIH grant to develop a TMB test on circulating tumor DNA.

An excerpt from MedCity News below:

   Colon, pancreatic, stomach, or ovarian cancer; it increasingly shouldn’t matter. In an era of precision medicine, the treatment approach should reflect the genetic makeup of the person’s tumor and the presence or absence of key biomarkers.
   That ethos was set in stone on Tuesday, with the landmark FDA approval of Merck’s checkpoint inhibitor, Keytruda (pembrolizumab), for patients with solid tumors that express so-called mismatched repair genes.
   In a statement, FDA noted the historic nature of its decision. “This is the first time the agency has approved a cancer treatment based on a common biomarker rather than the location in the body where the tumor originated.”
The approval is an accelerated approval, meaning that it can be subject to eventual re-review on the basis of required additional studies.