A plain language summary of publication of the efficacy and safety of individualized niraparib dosing based on baseline body weight and platelet count in the PRIMA/ENGOT-OV26/GOG-3012 trial.

WHAT IS THIS SUMMARY ABOUT?: This document provides a summary of results from the article that evaluated the safety and efficacy of the fixed and individualized starting doses of niraparib in the PRIMA study. The original article was published in the journal Cancer in March 2023. The PRIMA study included adult patients with newly diagnosed advanced ovarian cancer who had finished treatment with chemotherapy and surgery. Once patients entered the study, they were treated with an oral (by mouth) medication called niraparib or placebo (substance with no effects that a doctor gives to a patient instead of a drug). The amount of drug (dose) prescribed for patients to take at the start of treatment was determined by the study plan (a document that describes in detail how the study will be performed). Some patients were treated with a fixed starting dose (300 milligrams [mg] once daily), while others were treated with an individualized dose (200 or 300 mg once daily) based on how much they weighed and the results of their blood test. The individualized dose was tested to see if it improved patient safety without changing its efficacy (how well the drug worked).

WHAT WERE THE RESULTS?: The individualized starting dose of niraparib improved patient safety, with a lower proportion of patients experiencing side effects than the fixed starting dose. The individualized starting dose of niraparib also delayed the cancer from coming back (recurring) or getting worse (progressing) compared with placebo. The delay in the cancer coming back or getting worse with niraparib treatment was generally similar in patients who received the individualized starting dose and those who received the fixed starting dose of niraparib.

WHAT DO THE RESULTS MEAN?: The results support the use of the individualized starting dose of niraparib, which uses a patient's body weight and blood test results to determine how much drug they should receive at the start of treatment. The study found that the individualized starting dose improved safety compared with the fixed starting dose while still delaying the cancer from coming back or getting worse. Clinical Trial Registration: NCT02655016 (PRIMA study) (ClinicalTrials.gov).