Lutetium Lu 177 vipivotide tetraxetan was effective in patients with oligometastatic hormone-sensitive prostate cancer.
Lutetium Lu 177 vipivotide tetraxetan (Pluvicto) displayed promising efficacy and a mild adverse effect (AE) profile for the treatment of patients with oligometastatic hormone-sensitive prostate cancer (HSPC), according to data from the phase 2 BULLSEYE trial (NCT04443062).1
Findings from BULLSEYE presented in a poster during the
“[Lutetium Lu 177 vipivotide tetraxetan] resulted in a greater than 90% reduction in PSA [level] in greater than 50% of patients and 25% [of patients] had a complete biochemical response,” Bastiaan Privé, MD, PhD, a doctorate student in the Department of Radiology and Nuclear Medicine at Radboud University Medical Center in Nijmegen, Netherlands, and his coauthors wrote in the poster. “[Lutetium Lu 177 vipivotide tetraxetan] postpones castration for 25 months in 50% of patients.”
BULLSEYE was an open-label trial that enrolled patients with metachronous prostate-specific membrane antigen (PSMA)–expressing oligometastatic HSPC who were not amenable for radiotherapy or surgery.1,2 Patients were required to have experienced biochemical recurrence (PSA > 1.0 µg/L), have a PSA doubling time of less than 6 months, have at least 1 and no more than 5 fluorine-18 (18F)–PSMA-PET-CT positive metastases in the bones and/or lymph nodes, and have no prior exposure to hormonal therapy.2
Patients were randomly assigned 1:1 to receive lutetium Lu 177 vipivotide tetraxetan at 7.4 GBq for a total of 4 cycles with 6 weeks in between each cycle or SOC deferred ADT.1,2 Notably, patients in the control arm were permitted to crossover to receive lutetium Lu 177 vipivotide tetraxetan upon achieving the primary end point of the study.1
The primary outcomes were the proportion of patients with, and time to, disease progression, defined as the initiation of ADT, a 100% increase in PSA level since random assignment, and radiographic or clinical progression. Secondary outcomes included the change in PSA level after lutetium Lu 177 vipivotide and the proportion of patients who achieved at least a 50% decrease in PSA level from baseline, the changes in uptake of 18F-PSMA-PET-CT before and after 6 months of lutetium Lu 177 vipivotide tetraxetan, the size of soft tissue metastases per 18F-PSMA-PET-CT and whole body MRI after lutetium Lu 177 vipivotide tetraxetan, clinical progression, ADT-free survival, safety and tolerability, and quality of life.
At baseline, the median ages in the investigational and control arms were 69 years (IQR, 64-74) and 72 years (IQR, 67-76), respectively. Most patients in both arms had undergone prior prostatectomy (75.9% vs 79.3%) or radiotherapy (75.9% vs 65.5%). The median baseline PSA levels were 5.4 µg/L (IQR, 2.7-11) and 3.8 µg/L (IQR, 2.2-6.9), respectively. The median PSA doubling times were 3.4 months (IQR, 1.3) and 3.8 months (IQR, 1.4).
Most patients in the control arm went on to receive lutetium Lu 177 vipivotide tetraxetan (93%). Reasons for crossover consisted of no disease progression (52%), PSA progression (33%), and the initiation of a new systemic therapy (15%).
In terms of safety, the most common grade 1 adverse effects (AEs) among all patients who received lutetium Lu 177 vipivotide tetraxetan (n = 56) included dry mouth (59%), fatigue (46%), nausea (41%), and decreased lymphocyte count (34%). Grade 2 AEs included decreased lymphocyte count (28%) and dry mouth (7%). Decreased lymphocyte count (7%) and dry eye (2%) were the only grade 3 AEs; no grade 4 AEs were reported.
“[AEs] were mild and patients retained good quality of life,” Privé and his coauthors wrote in their conclusion. “[Lutetium Lu 177 vipivotide tetraxetan] is a promising new treatment in metachronous oligometastatic HSPC.”
Disclosures: The study authors noted that their trial was supported by The Dutch Prostate Cancer Foundation and Novartis.
