Picture of patient receiving a dancer drug to represent precision cancer therapies
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The precision cancer therapy pralsetinib, designed to target cancers with fusion mutations in the RET gene, has achieved good results in a phase I/II trial led by researchers at the University of Texas MD Anderson Cancer Center targeting different solid tumors with these types of mutations.

Published in the journal Nature Medicine, the study showed that pralsetinib achieved a disease control rate of 83% and an overall response rate of 57% across 23 patients enrolled in the trial.

“The RET proto-oncogene (RET) encodes a transmembrane receptor tyrosine kinase (proto-oncogene tyrosine protein kinase receptor RET) that has a physiological role in the embryonic development of the nervous system and the kidneys,” explain the authors.

Mutations in this gene, particularly abnormal fusions with other genes, can cause cancer. For example, they are found in up to 2% of non-small-cell lung cancer (NSCLC) tumors, 20% of papillary thyroid cancers and a small percentage of a number of other tumor types including ovarian, pancreatic and colorectal cancers.

Pralsetinib is one of a growing number of precision cancer therapies designed to be effective in a specific group of patients whose tumors carry certain mutations.

“We’ve had an explosion in clinical next-generation sequencing that allows us to understand shared biomarkers across multiple tumor types, and this study was important to determine if RET fusions are actionable across cancer types,” said corresponding author Vivek Subbiah, associate professor of investigational cancer therapeutics at the MD Anderson Cancer Center, in a press statement.

“We observed responses regardless of tumor type, prior therapy or gene fusion partner. These data validate RET as a tissue-agnostic target with sensitivity to RET inhibition.”

Overall, 29 patients with 12 different RET fusion–positive solid tumor types who were not candidates for or who had already received standard therapies were enrolled in the study. They were selected as part of a larger cancer treatment study. Fusions with the genes CCDC6 (26%), KIF5B (26%) and NCOA4 (13%) were most common.

A total of 23 patients had data that could be evaluated at the end of the study and the overall response rate was 57% over a median period of 12 months. Progression-free survival and overall survival were 7 and 14 months, respectively. Neutropenia and anemia were the most common adverse events at 31% and 14%, respectively.

“Although RET fusions are extremely rare beyond lung and thyroid cancers, these patients need effective therapies,” Subbiah said. “These findings demonstrate the potential for RET inhibitors to benefit patients across tumor types and show the power of precision medicine to match patients to the right targeted therapy based on the unique features of their cancer.”

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