By admin 
Leanna Stokes had gotten into the habit of asking her oncologist what might be next for her treatment, and for good reason. Stokes, a 36-year-old gymnastics manager from New Rochelle, New York, had received one of the most difficult diagnoses in oncology: metastatic pancreatic cancer. Her oncologist kept mentioning two syllables, KAY-ras, referring to her cancer’s mutation on the KRAS gene. Mutations in this gene can make cancers more aggressive. But for Stokes, it was a possible key to extending her life. She always mentioned this—KRAS, KRAS, KRAS, Stokes said of her oncologist. As Stokes proceeded to receive line after line of chemotherapy, she would remind herself, it’s there. It’s there. It’s there. Then finally, it was my turn.
Just a few years ago, such a refrain might have sounded odd to pancreatic cancer experts. For most of the nearly 50 years since KRAS was first discovered, scientists struggled to effectively drug the cancer protein. The KRAS gene, part of the RAS family of oncogenes, acts as a molecular switch that regulates cell growth and survival. When mutated, this switch becomes stuck in the "on" position, sending continuous signals that drive the rapid, uncontrolled proliferation of cancer cells. Because the KRAS protein is relatively smooth and lacks deep binding pockets where small-molecule drugs can latch on, it earned the daunting reputation of being "undruggable."
When Kevan Shokat, a chemist and professor at the University of California, San Francisco, finally discovered a hidden pocket on a rare subset of KRAS mutant cancers (KRAS G12C) in 2013, it was hailed as a monumental breakthrough. However, the first-generation drugs that followed, such as Amgen’s sotorasib (Lumakras) and Mirati Therapeutics’ adagrasib (Krazati), were a clinical disappointment for many. While they proved effective in certain lung cancer patients, for the roughly 1% of pancreatic cancer patients who could receive them, the drugs improved outcomes only marginally, with resistance forming rapidly. The biology of pancreatic cancer is uniquely hostile, characterized by a dense, fibrotic stroma that shields the tumor from both the immune system and traditional therapies.
We did not have a home run on the first effort, said Channing Der, a prominent pancreatic cancer researcher at the University of North Carolina, Chapel Hill. It’s fair to say we’ve been disappointed by the durability of the responses. Der, who has spent decades studying the RAS pathway, noted that the initial wave of inhibitors targeted the "off" or inactive state of the KRAS protein. The problem was that many tumors, particularly in the pancreas, found ways to quickly toggle the protein back into the "on" state, rendering the drugs useless within months.
But once Shokat had shown it could be done at all, the floodgates opened. The pharmaceutical industry shifted from skepticism to a gold rush, with more and more companies jumping into developing drugs for KRAS. New agents are now regularly moving into clinical trials, shifting the focus from specific mutations like G12C to broader "pan-KRAS" or "multi-RAS" inhibitors. The company leading this second wave has been Revolution Medicines, a Redwood City-based biotech focusing on the drug daraxonrasib (formerly known as RMC-6236). Unlike the first-generation inhibitors, daraxonrasib is a RAS-ON multi-selective inhibitor. It targets the active form of the KRAS protein, which is the state that actually drives the cancer’s growth.
This was the drug that Stokes got on her clinical trial. It transformed her life, she said, enabling her to live far longer than most patients with her diagnosis. For a patient with metastatic pancreatic ductal adenocarcinoma (PDAC), the five-year survival rate is a sobering 3%. Standard treatments usually involve aggressive chemotherapy regimens like FOLFIRINOX or gemcitabine plus nab-paclitaxel, which offer limited survival benefits and come with debilitating side effects. For Stokes, daraxonrasib represented a departure from the "scorched earth" approach of chemotherapy, offering a targeted strike against the driver of her specific disease.
The excitement surrounding Revolution Medicines’ candidate is not just anecdotal; it is grounded in compelling clinical data. In early-phase trials, daraxonrasib has shown the ability to shrink tumors across a variety of KRAS mutations, including G12D, G12V, and G12R, which collectively account for the vast majority of pancreatic cancer cases. This is a significant leap forward. While the G12C mutation is common in non-small cell lung cancer, it is rare in the pancreas. By developing a drug that can hit multiple versions of the KRAS mutation, Revolution Medicines is opening the door for nearly 90% of pancreatic cancer patients who carry some form of a KRAS mutation.
The impact of this research extends far beyond the pancreas. The KRAS mutation is the most frequent oncogenic driver in human cancers, appearing in approximately 25% of all solid tumors. Consequently, the success of daraxonrasib and similar agents could herald a new era for oncology, bringing new treatments for lung, colorectal, endometrial, and biliary tract cancers. Beyond Revolution Medicines, dozens of other companies are also testing promising KRAS inhibitors in the clinic. Firms like BridgeBio Pharma, Frontier Medicines, and Deciphera Pharmaceuticals are all racing to refine the next generation of inhibitors, exploring different molecular "hooks" and combination strategies to overcome the inevitable challenge of drug resistance.
One of the primary hurdles in treating KRAS-driven cancers is the ability of the cancer cell to bypass the inhibited protein. Cancer is an evolutionary machine; when one pathway is blocked, it often finds a detour. To combat this, researchers are looking into "vertical inhibition," where multiple points in the same signaling pathway are targeted simultaneously. Others are investigating "horizontal inhibition," combining KRAS inhibitors with immunotherapy or other targeted agents like SHP2 or SOS1 inhibitors. The goal is to create a "pincer maneuver" that prevents the tumor from adapting.
However, the path to a cure remains long. Even with the promising results seen in patients like Leanna Stokes, oncologists remain cautious. The durability of the response is the "holy grail" of KRAS research. If the cancer returns after a year, the drug is a bridge, not a solution. The challenge for Revolution Medicines and its competitors is to prove that these inhibitors can provide long-term remission. This requires not only potent drugs but also a deep understanding of why some patients respond and others do not. Biomarker research is currently underway to identify which specific genetic profiles are most susceptible to these new inhibitors.
For patients, the shift in the landscape is palpable. For decades, a diagnosis of pancreatic cancer was often met with a sense of hopelessness. The lack of progress in the field was so pronounced that it was frequently referred to as a "graveyard for drug development." Now, the conversation has shifted toward precision medicine. Stokes’ experience of repeating "KRAS, KRAS, KRAS" reflects a new reality where patients are increasingly aware of their tumor’s genomic profile. Genomic sequencing, once a luxury or a research tool, is becoming a standard of care, allowing oncologists to match patients with clinical trials that offer the best chance of success.
The financial stakes are also enormous. The market for KRAS inhibitors is projected to be worth billions of dollars, attracting massive investment from venture capital and big pharma alike. Bristol Myers Squibb’s $4.8 billion acquisition of Mirati Therapeutics in late 2023 underscored the industry’s belief in the long-term value of RAS-targeting therapies. As more data emerges from Phase 2 and Phase 3 trials, the competition will only intensify, potentially leading to a suite of approved drugs that can be tailored to the individual patient’s mutation.
Despite the corporate maneuvering and the complex biochemistry, the heart of the story remains the patients. For Leanna Stokes, the "turn" she waited for has meant more time—time that was never guaranteed given the statistics of her disease. Her story is a testament to the perseverance of researchers like Kevan Shokat and Channing Der, who refused to accept the "undruggable" label. It also highlights the courage of clinical trial participants who step into the unknown, providing the data necessary to save the lives of those who come after them.
As the oncology community looks toward the future, the focus is on refinement and expansion. Can these drugs be moved into earlier lines of therapy? Can they be used in the adjuvant setting to prevent recurrence after surgery? The answers to these questions will define the next decade of cancer care. While the "home run" that Channing Der spoke of may still be in the future, the current progress suggests that we are at least finally on the scoreboard. The "KAY-ras" mutation, once a harbinger of a quick and aggressive decline, is slowly being transformed into a target—a vulnerability that, when exploited, offers a glimmer of hope in one of medicine’s darkest corners. For Leanna Stokes and thousands like her, that hope is everything.