medwireNews: The NIBIT-MESO-1 trial suggests that retreatment with tremelimumab plus durvalumab could be a viable option for patients with unresectable mesothelioma who progress after initially benefiting from the combination.
The phase 2 study previously showed the efficacy and tolerability of the combination in 40 patients who had progressed on or refused prior platinum-based chemotherapy for inoperable pleural or peritoneal mesothelioma.
The current report focuses on 17 participants who derived a clinical benefit (partial response or stable disease) from the combination before progressing, and were therefore eligible for retreatment with up to four cycles of tremelimumab 1 mg/kg plus durvalumab 20 mg/kg every 4 weeks followed by nine cycles of maintenance durvalumab.
No patient had an objective response to retreatment as per immune-related RECIST criteria, but 41% achieved stable disease. Median progression-free survival from the start of retreatment was 3.5 months and median overall survival (OS) was 12.5 months.
A post-hoc analysis showed that median OS from the start of the trial was significantly longer for the retreated patients than for 15 patients who did not meet the criteria for retreatment and instead received chemotherapy after progression, at 25.6 versus 11.0 months.
Retreatment appeared to be well tolerated, with no immune-related adverse events of grade 3–4, while events of grade 1 or 2 were observed in 35% of participants, report Michele Maio (University Hospital of Siena, Italy) and co-researchers in The Lancet Respiratory Medicine.
And they conclude: “Despite the limitations of the study, including the small number of patients who received ICI [immune checkpoint inhibitor] retreatment and the nonrandomised study design, which prevent drawing firm conclusions, the clinical results support the efficacy and safety of ICI retreatment in patients who become refractory to initial ICI treatment, and further investigation is warranted for potential application of retreatment in the clinical practice.”
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