Poly (ADP-ribose) polymerase (PARP) inhibitors as maintenance therapy are superior to other maintenance therapies on outcomes in advanced ovarian cancer, according to a systematic review of the literature.
In extracting data from 50 full-text journal articles covering 18 clinical trials, and examining efficacy outcomes, investigators led by Holly Guy, MSC, a health economist from FIECON, Ltd, St. Albans, UK, found improvements in progression-free survival (PFS) “across the board” with PARP inhibitor maintenance compared with other types of maintenance. In addition, “only PARP inhibitor-containing therapies reported significant overall survival [OS] hazard ratios [HRs] below 1 across all trial populations,” they wrote in their abstract presented during the European Society of Gynecological Oncology Virtual Congress 2020.
The 18 clinical trials assessed clinical outcomes with first-line maintenance therapies and maintenance therapies initiated alongside first-line chemotherapy followed by a maintenance phase for advanced ovarian cancer. Only 2 of the 18 did not report PFS as an efficacy end point.
Of those that assessed first-line maintenance with a PARP inhibitor with PFS reported, HRs were 0.766 for pazopanib versus placebo in the AGO-OVAR16 trial, 0.30 for olaparib versus placebo in SOLO-1, 1.114 for pazopanib versus placebo in an East Asian substudy of AGO-OVAR16, 0.98 for pazopanib versus placebo in NCT01227928, 0.59 for olaparib plus bevacizumab versus placebo plus bevacizumab in PAOLA-1, 0.62 for niraparib versus in PRIMA, and 0.68 for veliparib versus placebo in VELIA/GOG-3005.
“No pattern was identified in relation to PFS amongst patients who were treated with a maintenance therapy following first-line platinum-based chemotherapy versus those who received a maintenance drug concurrently with first-line platinum-based chemotherapy and then continued with the maintenance treatment,” the authors noted.
Of those that reported OS as a secondary end point, HRs for OS in the PARP inhibitor studies were 0.96 (AGO-OVAR16), 0.95 (SOLO-1), and 0.7 (PRIMA).
“Therapies that included PARP inhibitors reported better PFS HR than other ovarian cancer maintenance therapies,” the investigators concluded. “In study populations including both BRCA mutation-positive and wild type, clinical benefit is conferred by both olaparib plus bevacizumab and niraparib, as indicated by PFS.”