Five-year follow-up data from the phase 3 SOLO-1 trial demonstrates a nearly five-year delay in disease progression with Lynparza compared with a delay of just over a year with placebo in women with newly diagnosed, advanced ovarian cancer harboring a BRCA gene mutation.
Women with newly diagnosed, advanced ovarian cancer harboring a BRCA gene mutation went three-and-a-half years longer without disease progression when they took the targeted drug Lynparza (olaparib) following their primary treatment compared with a placebo.
The results came from five-year follow-up data in the phase 3 SOLO-1 trial, reported Sept. 18 during the 2020 European Society of Medical Oncology virtual congress.
The drug was approved for this use in 2018, and the five-year results provide longer-term confirmation of its benefit.
Lynparza is a poly (ADP-ribose) polymerase, or PARP inhibitor, which works by interfering with the activity of an enzyme that repairs damaged DNA in cancer cells. Cancers that harbor BRCA gene mutations already have DNA-repair problems, and PARP inhibitors can make it even more difficult for these cells to survive.
Approximately 22% of patients with ovarian cancer have a mutation to the BRCA1 or BRCA2 gene, according to a press release issued by AstraZeneca, which is developing Lynparza along with MSD.
“Once a patient’s ovarian cancer recurs, it historically has been incurable. Even at an advanced stage, we have shown that maintenance treatment with Lynparza can help patients achieve sustained remission. Today’s results further underline the critical importance of identifying a patient’s biomarker status at the time of diagnosis to offer a treatment that may help delay disease progression,” José Baselga, executive vice president of oncology research and development for AstraZeneca, said in the release.
The trial tested the use of Lynparza tablets (300 mg twice daily) as a maintenance treatment, meaning that the drug was given after the completion of therapy for the disease as a means of helping to preserve health gains. It was the first maintenance treatment received by the patients.
The five years of data collected in the trial represented the longest follow-up analysis for any PARP inhibitor in the initial maintenance setting, according to the press release.
The trial included 391 patients with a BRCA1 or BRCA2 mutation who were in clinical complete or partial response following platinum-based chemotherapy.
Patients were divided into groups to receive Lynparza or placebo for up to two years or until their disease progressed. Twice as many patients took Lynparza as placebo. Patients who had a partial response at two years were permitted to stay on therapy at the investigator’s discretion.
The trial’s main goal was to measure progression-free survival (PFS), meaning the time from the start of treatment until disease worsening. Secondary goals included time until disease recurrence; time until a next treatment for the disease was needed; and length of life while on the study drug.
Data from the trial showed that patients who took Lynparza maintenance had a median PFS of 56 months compared with 13.8 months for those who took placebo. At five years, 48.3% of patients treated with Lynparza remained free from disease progression versus 20.5% on placebo. The median duration of treatment with Lynparza was 24.6 months versus 13.9 months with placebo.
The safety profile of Lynparza was consistent with previous observations. The most common side effects experienced by 20% of study participants or more were nausea (77%), fatigue/weakness (63%), vomiting (40%), anemia (39%) and diarrhea (34%). The most common serious side effects were anemia (22%) and neutropenia (9%), a blood count deficiency. A total of 12% of patients taking Lynparza discontinued treatment because of a side effect.
“For patients with newly-diagnosed BRCA-mutated advanced ovarian cancer, the benefit derived from two years of maintenance treatment with Lynparza continued long after treatment ended,” Dr. Susana Banerjee, a SOLO-1 trial investigator, consultant medical oncologist at The Royal Marsden NHS Foundation Trust and reader at The Institute of Cancer Research in London, said in the release. “After five years, almost half of women were free of cancer progression. These results represent a significant step forward in the treatment of BRCA-mutated advanced ovarian cancer.”