1108P - Outcomes of patients with unresectable or metastatic melanoma after cessation of immunotherapy following complete response or toxicities

Background

Checkpoint inhibitors (CPI) have changed the treatment paradigm for patients (pts) with advanced melanoma with significant improvements in overall survival. This study evaluated the outcomes of patients with advanced melanoma who were treated with CPI and had cessation of treatment due to either complete response (CR) or toxicities (tox).

Methods

From January 2015 to December 2021, 699 pts with unresectable stage III or stage IV melanoma were treated by a single prescriber across two centres in Brisbane, Queensland. In this retrospective study, we analysed 237 pts who had ceased CPI either due to CR, defined trial protocol or tox. We performed descriptive analyses of outcomes following cessation of CPI and subsequent treatment received after documented disease recurrence.

Results

Of the 237 pts who had ceased CPI, 176 pts had CR, 53 pts had treatment related tox and 8 pts had completed trial protocol. The average age of pts treated with CPI was 63 years old and the mean duration of treatment was 448 days. In this study, 71.3% of pts were BRAF wild-type, 27.4% of pts had a BRAF mutation and 1.3% of pts with uveal melanoma. 59.5% of pts had monotherapy CPI while 40.5% of pts had combination CPI. 182 pts (76.8%) had ongoing CR whilst 55 pts (23.2%) relapsed following cessation of therapy. In the cohort that relapsed, 36 pts had stopped CPI due to CR or defined trial protocol and 19 pts stopped following treatment related tox. The relapse rate was higher in pts stopped CPI due to tox (35.8%) compared to the cohort of pts who ceased due to CR or defined trial protocol (19.6%). Of those 55 pts who had relapsed, 22 were rechallenged with response, 12 were rechallenged with no response, 2 were rechallenged but ceased due to tox, 1 was rechallenged and is awaiting restaging, 7 had local therapy with either radiation therapy or surgery, 3 had different systemic therapy. 8 pts received best supportive cares.

Conclusions

Patients who had ceased CPI following CR had durable responses and a lower rate of relapse compared to pts with treatment related tox. On recurrence, retreatment with immunotherapy demonstrated response and could be considered a viable treatment option.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

V.G. Atkinson: Financial Interests, Personal, Advisory Board: BMS, MSD, Nektar, Novartis, Pierre Fabre, QBiotics; Financial Interests, Personal, Invited Speaker: BMS, MSD, Novartis, Pierre Fabre, Limbic; Financial Interests, Personal, Other, Travel Support: BMS. All other authors have declared no conflicts of interest.