Abstract 898P
Background
Immune checkpoint inhibitors (ICIs) are active in patients (pts) with R/M HNSCC. However, patient selection remains a challenge as the majority fail to respond. The effect of site of relapse on immunotherapy outcome has not been previously studied in R/M HNSCC. We therefore sought to assess the efficacy of immunotherapy according to site of relapse at baseline treatment.
Methods
A retrospective study was conducted at the Institut Universitaire du Cancer de Toulouse. All pts with R/M HNSCC who received immunotherapy as part of a clinical trial or as an EMA-approved indication from 2013 to 2019 were reviewed. Inclusion criteria were pts who received at least one dose of single or a combination of ICIs and for whom efficacy data were available. Pts were divided into three groups according to the site of relapse at baseline immunotherapy: loco-regional (LR), distant (D) or both (B). For pts treated with LR radiotherapy before ICI, radiation fields were reviewed and LR recurrences classified as infield, marginal or outfield.
Results
Of 87 pts treated with ICI, 57 met inclusion criteria: 18 in the LR group (31.6%), 14 in the D group (24.6%), 25 in the B group (43.9%). The median number of lines before immunotherapy was 1 in all groups. ICI was given as monotherapy in 63.6% of pts or as combination in 36.4%, with a balanced distribution between groups. There was no significant difference in terms of age, performance status, albumin and LDH levels. The median OS (95%CI) from the initiation of ICI was longer in the D group: 18.7 mo (6.4;33.8) vs. 7.6 mo (3.4;16.3) and 5.0 mo (4.1;12.4) in the LR and B groups, respectively. Objective response rate (ORR) and PFS between groups showed no significant difference. Radiation field data was available for 34 patients: outfield recurrences showed a higher ORR of 40% (2/5) compared to 12.5% (1/8) and 23.8% (5/21) for marginal and infield recurrences, respectively.
Conclusions
Our results show that pts with distant-only relapse treated with immunotherapy doubled OS benefit compared to pts with local relapse. We suggest that site of relapse should be stratified as loco-regional and distant-only in future clinical trials of immunotherapy for HNSCC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
C.A. Gomez-Roca.
Funding
Has not received any funding.
Disclosure
J. Delord: Financial Interests, Personal, Other, Consulting: Novartis; Financial Interests, Institutional, Other, Consulting: Roche/Genentech; Financial Interests, Institutional, Other, Consulting: BMS; Financial Interests, Institutional, Other, Consulting: MSD Oncology; Financial Interests, Institutional, Research Grant: Genentech; Financial Interests, Institutional, Research Grant: BMS; Financial Interests, Institutional, Research Grant: MSD Oncology; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Transgene. C.A. Gomez-Roca: Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Personal, Invited Speaker: Pierre Fabre; Financial Interests, Personal, Invited Speaker: Eisai; Financial Interests, Personal, Invited Speaker: Roche/Genentech; Financial Interests, Institutional, Other, Coordinating PI: BMS; Non-Financial Interests, Personal, Other, Steering committee member: BMS; Financial Interests, Personal, Other, Local PI: Foundation Medicine; Non-Financial Interests, Personal, Other, Steering committee member: Genentech; Financial Interests, Institutional, Research Grant: Roche/Genentec. All other authors have declared no conflicts of interest.