'Huge Step Forward' in Advanced Ovarian Cancer

Liam Davenport

June 03, 2023

UPDATED June 4, 2023 // Editor's note: This story has been updated with additional comments from Dr Christina Fotopoulou.

CHICAGO — New results in the treatment of advanced ovarian cancer have been welcomed by an expert not involved in the trial, even though the study showed an improvement in progression-free survival (PFS), and not yet overall survival.

The results come from the DUO-O trial, in which the PARP inhibitor olaparib (Lynparza) and immunotherapy with the anti-PD-L1 antibody durvalumab (Imfinzi) were added on to standard of care with paclitaxel/carboplatin chemotherapy and bevacizumab (Avastin) in patients with newly diagnosed with non-BRCA mutated advanced ovarian cancer.

A preplanned interim analysis revealed that the addition of durvalumab and olaparib was associated with a 37% improvement of PFS compared with the standard of care of chemotherapy plus bevacizumab alone.

This improvement increased to 51% in patients who had tumors positive for homologous recombination deficiency (HRD), which indicates the inability to effectively repair double-strand DNA breaks, a defect that is present in approximately 70% of ovarian cancers.

Co-principal investigator Carol Aghajanian, MD, chief of the Gynecologic Medical Oncology Service at Memorial Sloan Kettering Cancer Center in New York City, described the benefit seen with the novel combination therapy as both "statistically significant and clinically meaningful."

She was speaking at a press briefing held ahead of the American Society of Clinical Oncology annual meeting, where the results will be presented (abstract LBA5506) today.

Commenting for ASCO, Merry Jennifer Markham, MD, professor of medicine and chief of the division of hematology and oncology at University of Florida Health, Gainesville, said the results represents a "huge step forward."

She added the rate of progress it represents may not be "quick enough for our patients with advanced ovarian cancer but every little integral improvement that we can find in studies that are important, like this one, really means so much to that individual patient in that exam room."

Markham underlined that around 80% of women with epithelial ovarian cancer are diagnosed at an advanced stage, and "they know what they are facing," which is that "the vast majority" of them will have a recurrence "at some point."

"So while progression-free survival may not necessarily mean their overall survival, there will be hope it does. And I'm very excited to see where this study heads in that direction." Markham added that PFS is "very important to our patients," and the study does represent progress. "We are chipping away at improving outcomes for advanced ovarian cancer."

Moreover, "women are often disappointed when their tumor doesn't have a BRCA mutation because they know that that may limit some of their treatment options," and so the current study suggests that there are "options for all-comers" and "there is still hope."

Access to Treatment and Testing

Asked by Medscape Medical News whether there could be any access issues for patients clinically eligible for the novel combination, Aghajanian said that all of the drugs have been approved by the US Food and Drug Administration for indications that cover this usage.

They are also covered by medical insurance and, for those patients with financial toxicity, "there is access to co-pay assistance programs and the like."

She said that patients can then "be counseled on their expected benefit," based on their BRCA and HRD testing.

Markham, on the other hand, said she is "a little less optimistic" about access, explaining that she practices in the southern US, and "our populations [and] insurance coverages are a bit different."

She noted that, at her Florida institution, a "fair number of patients are underinsured," and they "ran into a lot of issues with people not being able to afford their co-pays," which can be "prohibitive."

"A large portion of my counseling has been and will continue to be around the benefit, but also the financial toxicity, that that individual patient may experience and the need for co-pay assistance programs or other support mechanisms," Markham said.

Aghajanian added that "financial toxicity and the access issue comes even prior to the treatment, in getting those BRCA1/2 tests and the HRD testing done, so patients have the information they need to make informed decisions."

"We do have disparities with genetic testing and genomic testing that need to be solved," she said.

Study Details

Previous studies, including SOLO1 and PAOLA-1, have shown that maintenance therapy with olaparib and bevacizumab improves outcomes in the first-line treatment of advanced ovarian cancer.

"However, there still remains unmet need, especially in some patient subgroups without a BRCA mutation," Aghajanian said.

While the addition of immunotherapy to standard of care has yet to show a clinical benefit in this setting in phase 3 trials, the phase 2 MEDIOLA study indicated that the combination of durvalumab, bevacizumab, and olaparib was active in non-germline BRCA-mutated, platinum-sensitive relapsed cancer.

The phase 3 DUO-O study therefore set out to determine whether this combination would be beneficial as a maintenance therapy in 1130 patients with newly diagnosed stage III or IV high-grade ovarian cancer without a tumor BRCA1/2 mutation.

Patients were required to have had no prior systemic therapy for ovarian cancer, and be naive to both PARP inhibition and immunotherapy. They also had to have completed upfront primary debulking surgery, or be scheduled to undergo the procedure.

After an initial cycle of paclitaxel/carboplatin chemotherapy, the patients were randomly assigned to one of three regimens:

  • Standard of care treatment, comprising chemotherapy plus bevacizumab and durvalumab-placebo, followed by maintenance therapy with bevacizumab, durvalumab-placebo, and olaparib-placebo (arm 1)

  • Chemotherapy plus bevacizumab and durvalumab, followed by maintenance therapy with bevacizumab, durvalumab, and olaparib-placebo (arm 2)

  • Chemotherapy plus bevacizumab and durvalumab, followed by maintenance therapy with bevacizumab, durvalumab, and olaparib (arm 3)

In the maintenance phase, bevacizumab was to be given for a total of 15 months, while durvalumab and olaparib, or their equivalent placebos, were prescribed for 24 months. Treatment was continued until disease progression, study completion, or another discontinuation criteria was met.

Aghajanian presented results from a preplanned interim analysis, with a date cutoff of December 5, 2022.

Among HRD-positive patients, those in arm 3 had a significantly longer PFS than those in arm 1, at a median of 37.3 months vs 23 months, or a hazard ratio of 0.49 (P < .0001).

In the intention-to-treat analysis, arm 3 was also associated with a significant improvement in median PFS over arm 1, at 24.2 months vs 19.3 months, or a hazard ratio of 0.63 (P < .0001), indicating that the trial met both of its primary endpoints.

While there was a numerical difference in median PFS between arm 2 and arm 1, at a median of 20.6 months versus 19.3 months, this was not significant. This means that relative contribution of adding durvalumab alone is not clear, Aghajanian commented, and said that this comparison "will be reassessed at the time of the final PFS analysis."

She added that a "PFS effect was observed across all subgroups for the arm 3 vs arm 1 comparison," including in the HRD negative subgroup, at a median of 20.9 months vs 17.4 months, or a hazard ratio of 0.68.

The safety and tolerability of the regimens were generally consistent with what is known for the individual agents, she commented.

Serious adverse events were reported in 34%, 43%, and 39% of patients in arms 1, 2, and 3, respectively.

The most common grade 3 or higher adverse events were neutropenia (in 26% of arm 1 patients, 28% of those in arm 2, and 31% of those in arm 3) followed by anemia (in 8%, 8%, and 24%, respectively).

Dose modifications were required in 72% of arm 1 patients, 80% of those in arm 2, and 85% of arm 3 patients. Treatment discontinuation was recorded in 20%, 26%, and 35%, respectively.

Tackling Underserved Patient Populations

Discussing the results, Christina Fotopoulou, MD, PhD, professor of gynecological cancer surgery in the Department of Surgery and Cancer, Imperial College London, UK, said that, while the regimen may seem new, the treatments involved are "veterans," and that they are nevertheless tackling previously underserved patient populations.

Fotopoulou, who was not involved in the study, noted that the results were highlyanticipated, and the study has delivered a "breakthrough in ovarian cancer." She nevertheless questioned the choice of the control arm, and pointed out that thehazard ratio in favor of the combination therapy is "relatively modest" considering that it involves three drugs.

Fotopoulou highlighted, however, that one of the most important results was in the HRD negative patients, which she characterized as the equivalent of the clinicians going to "the dark side of the moon." She said that "for the first time, we have a positive study in this patient population," although she underlined that the results are from an interim analysis.

The key question that remains, Fotopoulou said, is: "Why? What is making thedifference?" She noted that, unfortunately, the trial design does not allow the identificationof the relative contribution of olaparib and durvalumab.

The study was sponsored by AstraZeneca, and conducted in collaboration with the European Network of Gynaecological Oncological Trial Groups (ENGOT), GOG Foundation, Inc., and Myriad Genetic Laboratories, Inc.

Harter declares relationships with AstraZeneca, Clovis Oncology, Eisai, GlaxoSmithKline, Lilly, MSD Oncology, Roche, Sotio, Stryker, Zai Lab, Immunogen, Merck, Roche, Tesaro, and Genmab (Inst). Aghajanian declares relationships with AstraZeneca, Merck, Eisai, Repare Therapeutics, AbbVie (Inst), Clovis Oncology (Inst), and Genentech/Roche (Inst). Markham declares relationships with Pfizer, GlaxoSmithKline, Aduro Biotech (Inst), Lilly (Inst), Tesaro (Inst), Novartis (Inst), VBL Therapeutics (Inst), AstraZeneca (Inst), and Merck (Inst).

American Society of Clinical Oncology 2023 Annual Meeting: Abstract LBA5506. To be presented June 3, 2023.

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