1466P - Efficacy of immune checkpoint inhibitors (ICI) in renal cell carcinoma (RCC) venous tumor thrombus (VTT) shrinkage

Background

ICI, either in combination with other ICI or with VEGF tyrosine kinase inhibitors (TKI), is now the standard of care treatment for first line metastatic RCC patients (pts). The presence of renal cell carcinoma with a VTT is associated with a pejorative survival prognosis. Several ICI based neoadjuvant trials are ongoing. However, data regarding the efficacy of ICI in VTT shrinkage are scarce.

Methods

We performed a French multicenter retrospective study of pts with metastatic RCC with a VTT and treated in first line or beyond with ICI. The main objective was to assess the objective response rate (ORR) of ICI on VTT. Radiological assessment was performed by treating physician according to iRECIST criteria.

Results

Twenty-five pts were included, between January 2015 and December 2021, at the participating institutions. Median age at diagnosis was 65 years (range 37-88). IMDC risk group was intermediate (14/25; 56%) and poor for 11 pts (44%). Most frequent metastatic sites were lung (88%; 22/25), lymph nodes (56%; 14/25), bone (40%; 10/25) and liver (36%; 9/25). Seventeen pts (68%) were treated with ICI in first line, 7/25 (28%) in 2^ndline and 1 pt (4%) in 3^rd line. Fourteen pts were treated with anti-PD-L1 in combination with antiCTLA-4 therapy, 10 pts with ICI monotherapy and 1 with ICI in combination with antiangiogenic TKI. At baseline, median VTT diameter was 20 mm (range 7-85) and VTT extension according to Novick’s classification was I for 9pts, II for 7pts, III for 4pts, IV for 2 and unknown for 3 pts. After a median duration of treatment of 3 months (range 3-89), ORR was 36% including 3 complete responses (CR) and 6 partial responses (PR). Eleven pts presented a stable disease (SD) and 5 progression disease (PD) as best response on VTT. Three patients presented a reduction on VTT extension according to Novick’s classification.

Conclusions

These data highlight the efficacy of ICI to shrink VTT even if it seems to have little impact on VTT level of extension. Further studies are needed to assess the role of ICI in neoadjuvant setting.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

P. Bigot: Financial Interests, Personal, Advisory Role: BMS; Financial Interests, Personal, Advisory Role, and Hospitality: MSD, Ipsen; Financial Interests, Personal, Other, Hospitality: Pfizer, Astellas, Pierre Fabre. N. Martinez Chanza: Financial Interests, Personal, Advisory Board: Ipsen, Merck, Merck, Astellas; Financial Interests, Personal, Invited Speaker: Janssen. P. Barthelemy: Financial Interests, Personal, Advisory Board: BMS, MSD, Merck, Pfizer, Ipsen, Bayer, Janssen Cilag, Astellas, Novartis, Amgen; Financial Interests, Personal, Invited Speaker: AstraZeneca, Seagen. All other authors have declared no conflicts of interest.