Immunotherapy versus targeted therapy in the adjuvant setting for resected stage III melanoma: A single institution study.

Abstract

e21578 Background: Both immunotherapy (IO) and targeted therapy (TT) are approved as adjuvant (Adj) treatment for stage III melanoma, as they have proven to significantly decrease disease recurrence. While there is evidence to suggest overall survival (OS) benefit with TT, data demonstrating OS advantage with Adj IO is lacking. There are no prospective head-to-head trials to date comparing these two treatment modalities. Our aim is to determine whether Adj IO equally improves outcomes compared to Adj TT. Methods: We retrospectively analyzed 104 patients (pts) with resected stage III melanoma who received Adj IO or TT from 1/2016 - 12/2021. Relapse free survival (RFS), distant metastasis free survival (DMFS) and OS rates were assessed between the 2 groups. Results: Of 104 pts, 78 received IO (91% nivolumab, 7% pembrolizumab, 2% other) and 26 pts TT (100% dabrafenib/trametinib). Median follow up was 21 months. At data cutoff, among the 26 pts who received TT, 50% completed 1 year of planned therapy, whereas 50% discontinued TT prematurely (42% due to adverse events [AEs], 8% due to disease relapse). Among the 78 pts who received IO, 70% completed 1 year of planned treatment or continued to receive IO at the end of the study, whereas 30% discontinued IO prematurely (18% due to disease relapse, 12% due to AEs). Relapsed disease was noted in 6/26 (23%) and 27/78 (34.6%) pts of the TT and IO groups, respectively. With regards to location of recurrence, in the TT group 2/6 pts relapsed locally and 4/6 distally, whereas in the IO group 14/27 pts relapsed locally and 13/27 distally. The estimated median RFS of the TT vs IO groups was not reached (NA) (95% Cl: 17 months, NA) vs. 30 months (95% CI: 17 months, NA) respectively, which was not statistically significant (p = 0.49). Comparison of DMFS rate was found not to be statistically significant between the 2 groups (p = 0.86). Finally, median OS was NA in either group. At the end of the study 91% and 90.5% of the pts in the TT and IO arms, respectively, were still alive. The most common AEs in the TT group were fatigue (23%), fever (23%), nausea/vomiting (19%), whereas in the IO group were fatigue (22%), hypothyroidism (14%), diarrhea/colitis (10%), pruritic rash (9%). Conclusions: Both TT and IO appear to equally decrease disease recurrence, locally or distally, when given as Adj therapy for stage III melanoma. Prospective, randomized control trials with longer follow up and larger sample size are warranted to determine any difference in potential OS benefit.[Table: see text]