medwireNews: Maintenance treatment with avelumab improves the long-term outcomes of advanced urothelial cancer patients regardless of their response to first-line chemotherapy and receipt of second-line therapy, suggest exploratory analyses of the JAVELIN Bladder 100 trial.
The findings were presented in posters at the 2022 ASCO Annual Meeting in Chicago, Illinois, USA, and follow the primary analysis showing a significant overall survival (OS) and progression-free survival (PFS) advantage with the addition of maintenance avelumab to best supportive care (BSC) in patients who had not progressed after four to six cycles of platinum-based chemotherapy.
The first of the exploratory analyses – conducted at a median follow-up of at least 38 months – showed that maintenance avelumab benefited patients irrespective of whether they had a complete response, partial response, or stable disease after first-line chemotherapy.
Specifically, among the 179 participants with a complete response, median OS was 39.8 months with avelumab plus BSC and 26.8 months with BSC alone, while among the 326 patients with a partial response and the 195 with stable disease, the median OS times were 19.2 versus 12.8 months and 22.3 versus 14.0 months, respectively.
Investigator-assessed PFS was similarly prolonged for patients who received the PD-L1 inhibitor plus BSC relative to those given BSC alone irrespective of chemotherapy response, at median durations of 9.5 versus 5.1 months in the complete response subgroup, 3.8 versus 1.9 months in the partial response subgroup, and 5.6 versus 2.0 months in the stable disease subgroup.
Begoña Pérez-Valderrama (Hospital Universitario Virgen del Rocío, Seville, Spain) and co-researchers highlighted that the long-term safety profile of maintenance avelumab “was consistent” across chemotherapy response subgroups, with a similar incidence of treatment-related adverse events (TRAEs) of at least grade 3, serious TRAEs, and AEs leading to avelumab interruptions.
But a higher proportion of patients in the complete response subgroup discontinued avelumab due to AEs than those in the partial response or stable disease subgroups, at 23.3% versus 10.0% and 12.8%, respectively.
The second poster focused on the outcomes of patients who received second-line treatment after discontinuing maintenance avelumab. Joaquim Bellmunt (Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA) and co-investigators explained that data on such patients “are limited.”
Of the 307 patients in the avelumab plus BSC arm who had discontinued the PD-L1 inhibitor at data cutoff, 185 had received second-line treatment that included rechallenge with platinum-based chemotherapy or other anticancer therapy, while 122 had not.
Bellmunt and colleagues reported that “[l]ong-term OS (in the context of historical data) was observed in patients who received avelumab” irrespective of whether they did or did not receive second-line treatment after discontinuing the PD-L1 inhibitor, at a median of 19.9 and 18.2 months, respectively.
But they noted that “[t]he subgroup of patients who discontinued avelumab with no [second-line] treatment reported is likely to be heterogeneous and may include patients who discontinued avelumab following early disease progression or toxicity in addition to patients who discontinued after experiencing long-term disease control.”
OS was also prolonged regardless of the nature of the second-line treatment, at a median of 22.5 months for those who were rechallenged with chemotherapy and 19.1 months for those who received other anticancer treatment, including a PD-1 or PD-L1 inhibitor.
“These findings further support avelumab [first-line] maintenance as standard of care in this treatment setting,” conclude Bellmunt et al.
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This independent news story was supported by an educational grant from Pfizer and Merck Healthcare KGaA, Darmstadt, Germany