Primary and Secondary Efficacy End Points
At data cutoff of June 7, 2024, median follow-up was 25.3 months for the Nubeqa group and 25 months for the placebo group. The median rPFS for Nubeqa plus ADT was not reached, meaning less than half of patients did not show disease progression, compared with 25 months for placebo plus ADT. At 24 months, the rate of rPFS was 70.3% for the Nubeqa group versus 52.1% for the placebo group.
The rPFS benefit with Nubeqa was consistent across all analyzed subgroups. For patients with low disease volume, the hazard ratio (HR; a statistical measure comparing the risk of an event between two groups) was 0.3 compared with an HR of 0.6 for those with high-volume disease. Those with prior local therapy had an HR of 0.34 whereas those with no prior local therapy had an HR of 0.59.
Although OS was not mature and was not reached in both groups, the stratified HR was 0.81 favoring Nubeqa. Adding Nubeqa also showed a benefit across other secondary focuses including time to metastatic castration-resistant prostate cancer, time to PSA progression, time to initiation of subsequent systemic therapy and time to pain progression. It also led to 62.6% of patients with PSA less than 0.2 nanograms/milliliter at any time during treatment, compared with only 18.5% in the placebo group.
Safety of Adding Nubeqa
The median treatment duration was 24.2 months in the Nubeqa group compared with 17.3 months for the placebo group. Incidence of treatment-emergent adverse events (TEAEs; treatment induced side effects) was similar between the groups, with 91% any-grade and 30.8% grade 3 (severe) or 4 (life threatening) TEAEs with Nubeqa plus ADT and 90% any-grade and 30.3% grade 3 or 4 with ADT plus placebo. There was a rate of 4.7% grade 5 (fatal) TEAEs in the Nubeqa group versus 5.4% for the placebo group. Serious TEAEs occurred at a rate of 23.6% in the Nubeqa group versus 23.5% in the placebo group and 6.1% discontinued treatment due to TEAEs in the Nubeqa group, a lower rate than the 9% in the placebo group.
When looking at TEAEs associated with ARPIs in particular, they were similar across the groups. Fatigue, mental impairment disorder, hypertension, cardiac arrythmias, coronary artery disorders, heart failure, falls, bone fracture, vasodilation (the widening of blood vessels) and flushing, diabetes and hyperglycemia, and rash all occurred in fewer than 10% of patients in either group and exposure-adjusted incidence rate per 100 patient years was also similar in the Nubeqa and placebo groups.
“[Nubeqa] and ADT significantly improved rPFS in patients with mHSPC, showed a benefit across all secondary endpoints, [and] had a favorable safety profile, confirming previous studies using [Nubeqa],” said Saad. “We believe that Nubeqa and ADT, without the need of docetaxel, could become an additional standard of care for mHSPC.”
For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.