The rise of genomic copilots in drug development

The companion diagnostic was once a niche sidekick in oncology, a modest tool for identifying the right patients for a small set of targeted therapies. Today, it is evolving into something more ambitious: a complex, central player in the drug development process. What began with single-gene assays has expanded into broad genomic profiling and liquid biopsy, with regulators, payers, and industry all adjusting to this new reality.

The contours of “companion 2.0” are beginning to emerge, and they suggest a world where tests function less like gatekeepers and more like copilots guiding the therapeutic journey.

The shift has been swift. In the 1990s, HER2 testing was the quintessential CDx, matching patients to Herceptin (trastuzumab) in breast cancer. Two decades later, the field is crowded with next-generation sequencing platforms that can detect hundreds of alterations in a single test. Foundation Medicine’s FoundationOne CDx, Guardant Health’s Guardant360 CDx (Nasdaq: GH), and Thermo Fisher’s Oncomine Dx (NYSE: TMO) are no longer niche instruments but staples in oncology drug labeling.