This study highlights the use of an oral medication with an improved formulation, with data suggesting no difference in health-related quality of life vs placebo.

— Eloise Chapman-Davis, MD

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Eloise Chapman-Davis, MD, a gynecologic oncologist at New York-Presbyterian and Weill Cornell Medicine, commented on the SOLO2 trial results for The ASCO Post.

“SOLO2 is the third randomized trial to evaluate the use of maintenance therapy in a selected subgroup of ovarian cancer patients with germline BRCA mutations. These results are exciting in that it is the second study to report an extension in progression-free survival early in the treatment course for patients with recurrent cancer—from around 6 months to 3 to 4 times longer,” Dr. Chapman-Davis said. “This was accomplished without requiring infusions or multiple hospital visits, which can be the most important thing to patients.”

Investigator vs Blinded Central Review

She commented on the large difference in progression-free survival between the investigator assessment and the blinded central review. “This may not reflect the true clinical benefit that would be seen in the general population,” suggested Dr. Chapman-Davis. The outcomes and reported hazard ratios (HR) for the two assessments (19.1 vs 5.5 months, HR = 0.30; and 30.2 vs 5.5 months, HR = 0.25) appear to fall within the range of recently reported data from the NOVA trial of niraparib.¹ In that study, the progression-free survival advantage was similar to that seen in the SOLO2 cohort of BRCA-mutated patients: 21.0 vs 5.5 months (HR = 0.27), she pointed out.

“This would suggest that the overall benefit probably exists somewhere in between 19 and 30 months,” she figured. “Regardless of the exact benefit, the SOLO2 trial clearly has added to the evidence promoting the use of poly (ADP-ribose) polymerase (PARP) inhibitors as possibly the standard of care as maintenance therapy for patients with relapsed platinum-sensitive ­BRCA-mutated ovarian cancer.”

Quality of Life

Dr. Chapman-Davis added that quality of life for patients undergoing maintenance therapy should remain the most important factor to both patients and providers. “This study highlights the use of an oral medication with an improved formulation, with data suggesting no difference in health-related quality of life vs placebo,” she noted. “The amount of nausea and vomiting reported with this drug appears to be equivalent across all reported PARP-inhibitor trials. This suggests the importance of selecting appropriate patients and being proactive with the management of side effects. The findings of anemia as the primary grade 3 toxicity is also worth noting, as it can lead to worsening fatigue. This is something that needs to be addressed during the course of treatment, with the goal being to provide early interventions.”

Clinical Implications

Although olaparib (Lynparza) has not yet received U.S. Food and Drug Administration approval for this indication, based on the benefits shown in two large phase III trials, she would be ready to use olaparib maintenance in her practice. This treatment, she said, provides an answer to a frequent question: What can patients do to prevent their cancer returning again? “This is something I can offer that may make patients feel proactive while providing an actual progression-free survival benefit,” offered Dr. Chapman-Davis.

She added that it is important to await the mature overall survival data and information on the tolerability of subsequent treatments. “This is what makes the data on time to subsequent therapy important,” she said, “and it appears to be longer in the olaparib arm.”

Future data regarding the effect of subsequent use of PARP inhibition after treatment with a PARP inhibitor may also be interesting and requires further study, she indicated. “As we re-use platinum in platinum-sensitive patients now with success, what would be the role of re-utilization of PARP inhibitors? ■

Disclosure: Dr. Chapman-Davis reported no potential conflicts of interest.

Reference

1. Mirza MR, Bonk BJ, Herrstedt J, et al: Niraparib maintenance therapy in platinum-sensitive, recurrent ovarian cancer. N Engl J Med 375:2154-2164, 2016.