Grail just learned what happens when the most anticipated clinical trial in cancer diagnostics misses its mark. The stock lost nearly half its value on Friday.
The company’s Galleri blood test — designed to detect multiple types of cancer from a simple blood draw — was supposed to be the future of early screening. England’s National Health Service ran a three-year trial involving 142,000 participants to test whether adding Galleri to standard screening could shift cancer diagnoses to earlier, more treatable stages. The primary endpoint: a statistically significant reduction in Stage III and IV cancer diagnoses. It didn’t happen.
That single data point — “primary endpoint not met” — is the one that matters most. Insurers, regulators, and health systems all anchor their decisions on primary endpoints. Miss it, and the path to widespread adoption gets exponentially harder. GRAL dropped 49.8% to $51, hitting a session low of $45.51. The stock had nearly doubled over the past year on hopes for strong results.
But dig past the headline and there’s nuance worth noting. Grail says the data showed “a clinically meaningful reduction in Stage IV diagnoses” and higher early-stage detection for a pre-specified group of 12 deadly cancers. CEO Bob Ragusa called it “the strongest evidence to date” for multi-cancer screening’s potential. The company plans to extend follow-up by six to twelve months, betting that the statistical significance emerges once Stage III patients are treated and tracked longer.
The FDA angle adds another layer of complexity. Grail filed for U.S. approval last month based on data from a smaller domestic trial and first-year UK data — not the full three-year results. TD Cowen’s Dan Brennan says the regulatory risk is “smaller” because the FDA is expected to rely on clinical validity data from multiple studies rather than this one trial. Guggenheim’s Subbu Nambi agrees: the miss hurts UK adoption prospects more than U.S. chances.
Here’s the bull case for the patient: Grail closed Q4 with $904 million in cash against a now-$2.1 billion market cap. Revenue climbed 14% to $43.6 million. The company moved 185,000 Galleri tests in 2025. That cash cushion buys time to extend the trial and pursue the Medicare pathway. The next big catalyst is the ASCO Annual Meeting in late May, where detailed data presentations could reshape the narrative entirely.
The bear case is simpler: the test didn’t do what it was supposed to do, and no amount of “favorable trends” will change that until the numbers prove otherwise. This is now a show-me story, and the stock will trade like one.