Satya Das, MD, MSCI, assistant professor of Medicines devised the clinical score system, which designates points according to organ involvement, types of prior treatment, symptoms, and other factors.
Data from a four-year study, published in JAMA Network Open, indicate that the scoring system may be a clinical tool for patients being considered for PRRT.
PRRT is a molecular and radiation therapy, where a cell-targeting protein is combined with a small amount of radioactive material to create a radiopeptide. When injected into a patient’s bloodstream, this radiopeptide binds to neuroendocrine tumor cells and delivers radiation directly to the cancer cells.
The clinical score divided patients into groups greater than 4 points and less than or equal to 4 points.
The researchers found that among patients who received three to four doses of PRRT, those with a score of 4 or less experienced a median progression-free survival which was not reached (NR) compared to 16.92 months in patients with a score of greater than 4. Quite strikingly, this same trend was observed about overall survival.
Patients who received partial doses of one to two treatments had worse outcomes than those who received the full dose regimen or no PRRT treatment at all. Researchers hypothesized that a minimum of three doses are needed to achieve a meaningful threshold of DNA damage in neuroendocrine tumors to stop tumor growth.
The clinical score is the first validated clinical metric that can predict the anticipated benefit from PRRT for a given patient. We are already using it in the oncology clinic to guide patients about to start the therapy, said Das, the study corresponding author.
The findings suggest that treatment outcomes may be optimized when patients are less pretreated with other therapies and possess a lower degree of metastatic involvement.
However, other results from ongoing clinical trials are needed to confirm this suggestion.
The optimal sequencing of PRRT remains a great unknown in neuroendocrine tumors.
Our clinical score points toward the benefit of earlier utilization of PRRT with lutetium dotatate, which is consistent with preclinical data suggesting the DNA damaging ability of the drug is optimized with lower disease volume, said Das.