Daraxonrasib Drug Resistance in Advanced Pancreatic Cancer Treatment
Advanced pancreatic cancer treatment faces a significant hurdle as tumors develop resistance to the targeted drug daraxonrasib after a median period of about seven months. Approved in August, the medication initially doubles the average survival time for patients with advanced pancreatic cancer by blocking the KRAS protein that cancer cells need to survive. Specialists from Dana-Farber Cancer Institute and Revolution Medicines are currently investigating how tumors evade this targeted therapy to find ways of prolonging patient survival. Andrew Aguirre, a pancreatic cancer specialist at the Dana-Farber Cancer Institute in Boston, noted that cancer specialists were not surprised when late last month former Nebraska Senator Ben Sasse announced that his stage 4 pancreatic cancer had developed resistance to a cutting-edge treatment, as nearly all pancreatic cancer patients taking the drug eventually develop resistance. Looking to the future, Sasse expressed confidence that the work—conducting science in patients, as he calls it—will someday
lead to cures.
Clinical Biopsies Reveal Cellular Changes After Daraxonrasib Treatment
To understand how resistance develops, researchers recruited 66 patients with advanced pancreatic cancer who were already enrolled in an early-stage clinical trial for daraxonrasib. Participating organizations included Break Through Cancer, the Lustgarten Foundation, and drug manufacturer Revolution Medicines. Patients underwent three separate tumor biopsies: one before treatment started, a second two weeks after initiation, and a final biopsy when the medication stopped working.
The initial biopsies showed that daraxonrasib successfully reduced tumor cell counts by half within two weeks. However, the remaining cancer cells changed significantly in appearance. Before treatment, the cells looked aggressive, malformed, and extremely abnormal. Two weeks later, the surviving cells appeared similar to cells that typically respond to chemotherapy. According to Mark Goldsmith, president and chief executive officer of Revolution Medicines, this shift suggests that combining daraxonrasib with chemotherapy might improve patient outcomes.
Blood Samples Point to KRAS Protein Overproduction
In addition to tumor biopsies, researchers examined blood samples from 44 advanced pancreatic cancer patients taken before treatment and after their tumors became resistant to daraxonrasib. These blood samples contained fragments of tumor cell DNA that provided further clues about how the cancer adapts. Researchers examined samples obtained before treatment with daraxonrasib and after the tumors developed resistance to the drug, noting that the blood can contain DNA fragments released by cancer cells. More than half of the resistant tumors flooded their cellular environments with abundant quantities of the KRAS protein, effectively bypassing the drug’s blocking mechanism.
Researchers are now exploring whether patients should receive two or more KRAS inhibitors simultaneously, given that more than 90 different KRAS inhibitors are currently in clinical trials. Tyler Jacks, president of Break Through Cancer and founding director of the Koch Institute for Integrative Cancer Research at MIT, confirmed that the research collaborative secured a new round of funding. This financing will support studies examining how tumors respond to daraxonrasib when paired with other therapeutic approaches. While the exact resistance mechanisms for a subset of patients remain unknown, scientists continue to analyze non-genetic changes in both cancer cells and the surrounding tumor microenvironment.
Frequently Asked Questions About Daraxonrasib Resistance
How long does daraxonrasib typically work before patients develop resistance?
The targeted medication generally remains effective for about seven months before tumors develop resistance and the treatment stops working.
Which organizations funded the clinical study on daraxonrasib resistance?
The research effort was supported by three groups: Break Through Cancer, the Lustgarten Foundation, and Revolution Medicines.
How many patients provided blood samples for the DNA fragment analysis?
Researchers examined blood samples obtained from 44 advanced pancreatic cancer patients both before treatment and after their tumors developed drug resistance.
Worth a look