The Undruggable Protein Gets Its Drug
The Trial That Worked
Five hundred people with metastatic pancreatic cancer, all of whom had already failed a first round of chemotherapy, enrolled across North America, Europe and Asia in a phase 3 trial called RASolute 302, led by Dr. Brian Wolpin at the Hale Family Center for Pancreatic Cancer Research at Dana-Farber. Standard second-line chemotherapy for pancreatic cancer that has progressed past a first round buys a median of well under a year, and the trial's own chemo arm confirmed it: 6.7 months. Half the trial got a pill called daraxonrasib, a RAS-targeted therapy from Revolution Medicines; half got standard chemotherapy. The results, published in the New England Journal of Medicine, are the kind that make a data monitoring committee call an early stop. Median survival was 13.2 months on daraxonrasib versus 6.7 months on chemotherapy, a 60 percent reduction in the risk of death (hazard ratio 0.40, the odds this is noise are close enough to zero to ignore). At 12 months, 53.3 percent of the daraxonrasib group was still alive, versus 18.7 percent on chemo. On August 26, the FDA approved the drug as Rasonque, more than six months ahead of its scheduled decision date. Regulators do not usually move early because a drug worked a little. They move early when a drug worked like this.
Thirty Years Undruggable
RAS is a small protein that acts as a molecular switch inside almost every cell, flipping to 'on' when it binds a molecule called GTP and telling the cell to grow and divide, then flipping back 'off' once that job is done. Mutations found in roughly 30 percent of all human cancers, including this one, jam the switch in the 'on' position, so the growth signal never stops. Drug companies spent nearly four decades trying to block it and mostly failed, because the RAS protein's surface is almost perfectly smooth, without the pocket or groove most drugs need to grip onto. Daraxonrasib takes a different route: it binds mutant RAS together with a chaperone protein called cyclophilin A, forming a three-part complex that only exists while RAS is locked in its active, GTP-bound state, and that complex physically blocks RAS from reaching the downstream proteins it needs to relay the growth signal. The molecule does not have to out-wrestle a smooth surface. It waits for the mutation to create a new one, then plugs it. That is why Revolution Medicines calls the platform RAS(ON): the drugs are built to grip only when the switch is stuck on, which happens to be exactly the shape a RAS-driven tumor cannot hide.
The Price Of Proof
Revolution Medicines set Rasonque's wholesale price at $39,800 a month, about $477,000 a year, more than double Keytruda's list price, for a drug now approved in one indication on data from roughly 500 trial patients. That price is a wager on the pipeline behind it: the company already has daraxonrasib running in three more global phase 3 pancreatic cancer trials plus one in non-small-cell lung cancer, and a second RAS drug, zoldonrasib, holds FDA Breakthrough Therapy Designation in lung cancer. Pancreatic cancer is rare enough that the real commercial prize sits in lung and colorectal disease, both far more common and both driven by the same class of mutation in a large share of cases; analysts have projected blockbuster, multibillion-dollar peak sales for the RAS(ON) franchise if those trials read out. The population this platform is ultimately built to reach includes Japan and Korea, which carry the region's highest pancreatic cancer incidence, 8.5 and 6.7 cases per 100,000 people, inside a region where five-year survival for the disease sits at 9.7 percent overall. None of that changes what RASolute 302 actually proved, which is survival in one specific, previously treated population. It does explain why a single pancreatic cancer trial just moved a company's entire valuation.
Rasonque is approved and priced as of this week, built on a survival number real enough to stop a monitoring committee early. What it has not yet done is show earlier-stage efficacy: a non-small-cell lung cancer trial pairing daraxonrasib with chemotherapy is still running, and a frontline pancreatic cancer trial is still enrolling. It has also not yet done the work of convincing an insurer that $477,000 a year is a price rather than a test. Those readouts are where that argument gets made next.
Sources
- FDA approves first-in-class targeted therapy for metastatic pancreatic cancer (fda.gov)
- RASolute 302 phase 3 results, NEJM (nejm.org)
- Dana-Farber: FDA approves daraxonrasib following landmark trial (dana-farber.org)
- Yahoo Finance: what will daraxonrasib cost (finance.yahoo.com)
- BioPharma Dive: Rasonque price and launch sales projections (biopharmadive.com)
- Revolution Medicines: first patient dosed in phase 3 trial (ir.revmed.com)