Dr. Gonzalez-Martin on the PRIMA Trial Design in Ovarian Cancer

Antonio González-Martín, MD, co-director, Department of Medical Oncology, Clinica Universidad de Navarra, discusses the design of the phase III PRIMA trial (ENGOT-OV26/GOG-3012) in ovarian cancer.

The PRIMA study examined patients with high-grade serous or intermediate-grade stage III or IV cancer with microscopic residual disease after primary debulking surgery, or those who received neoadjuvant chemotherapy, regardless of their residual disease after interval debulking surgery, explains González-Martín. All patients were platinum-sensitive, meaning they achieved a complete response or partial response to chemotherapy.

Tissue was also collected for biomarker analysis and screening using the Myriad myChoice CDx assay to evaluate the homologous recombination deficiency (HRD) status of the tumor.

Patients were randomized 2:1 to receive either niraparib (Zejula) or placebo. Patients were randomized within 12 weeks of finishing the last cycle of chemotherapy. Niraparib was administered once daily for the duration of 36 months or until disease progression. At the initiation of the study, niraparib was administered at a fixed dose of 300 mg once daily, but the protocol was amended to allow patients to receive a lower dose of 200 mg, depending on their baseline body weight and platelet count. This was because data showed that individualized dosing may have a beneficial effect on niraparib-induced myelosuppression, explains González-Martín.

The primary end point of the study is progression-free survival, according to radiological RECIST criteria by blinded independent central review, says González-Martín. A hierarchal analysis of patients with HRD was also performed, concludes González-Martín.