1131P - Management of metastatic uveal melanoma (MUM) patients on tebentafusp in a real-world setting

Background

Tebentafusp (TEBE), a bispecific T-cell engager targeting HLA-presented gp100 peptide, was approved for treatment-naïve (TN) MUM HLA-A*02:01+ pts. In its pivotal trial, pts attended weekly outpatient (OP) visits and the duration of premedication was not defined. Additional data on drug administration, safety, and efficacy of a tertiary center may provide insight into optimal premedication and an ideal follow-up schedule in the real-world setting.

Methods

We assessed MUM pts treated with TEBE at our center from Jun/2021-Nov/2022. Data on adverse events (AE), OP visits and discontinuation of premedication were analyzed. Efficacy outcomes included OS, PFS, time-to-TEBE discontinuation (TTD), and best response (BOR - clinician’s assessment). Survival was estimated using Kaplan-Meier; categorical variables were analyzed using logistic regression, Chi-square/Fisher’s exact tests.

Results

We identified 36 pts. Median age was 64 (30-90); 21 (58.4%) were male. At TEBE initiation, 22 (61%) pts had M1a disease. 20 pts (55.6%) had only 1 metastatic site, and 19 (53%) presented with liver-only disease. Extrahepatic involvement occurred in 17 (47%) pts. 25 pts (69.4%) were TN. Tumor reduction (TR) occured in 5 (14%) and disease control (DC) in 23 (64%) pts. The 1y OS was 68% (median: NR). Median PFS and TTD were, respectively, 6 (95%CI 3.8-8.1) and 9 mo (95%CI 4.6-13.3), with 1y PFS and TTD of 14% and 35.4%. Pts whose BOR was TR or SD had longer TTD when compared with those experiencing PD (12 vs 4 mo, p<0.01). All pts developed AE, most frequently rash (n=33), fever (n=23), and pruritus (n=14); 30.5% had G3/4 AE, with rash and hypoxemia occurring in 45% and 27%, respectively. M1a stage was associated with higher DC rate (p=0.03) and lower incidence of fever (p<0.01); rash was the only factor associated with DC in the multivariate analysis (p<0.01). The median number of inpatient doses was 4 (3-18). In the OP setting, 19 pts (53%) were switched to q3 week visits after a median of 6 doses (6-39). For 19 pts (53%), premedications were successfully stopped after a median of 7 doses (4-27).

Conclusions

Our data supports the reduction of OP visits and holding premedication after the resolution of AE. The promising activity of TEBE was confirmed in this cohort mostly comprised of TN pts.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M.F. Ribeiro: Financial Interests, Invited Speaker: Bristol Myers Squibb. S. Saibil: Financial Interests, Advisory Board: Janssen, Novartis, Sanofi, Immunocore; Financial Interests, Funding: Iovance Biotherapeutics. A. Spreafico: Financial Interests, Advisory Board: Merck, Bristol Myers Squibb, Oncorus, Janssen, Medison, Immunocore; Financial Interests, Research Grant: Novartis, Symphogen, Bristol Myers Squibb, AstraZeneca/MedImmune, Merck, Bayer, Surface Oncology, Northern Biologics, Janssen Oncology/Johnson and Johnson, Roche, Regeneron, Alkermes, Array Biopharma/Pfizer, GSK, NuBiyota, Oncorus, Treadwell, Amgen, ALX Oncology, Genentech, Seagen, Servier. M.O. Butler: Financial Interests, Research Grant: Merck, Takara Bio, Novartis; Financial Interests, Advisory Board: Merck, Bristol Myers Squibb, Novartis, Adaptimmune, InstilBio, Iovance, Sun Pharma, GSK, Sanofi, LaRoche Posay, Pfizer, Medison, IDEAYA, Regeneron; Financial Interests, Invited Speaker: Bristol Myers Squibb, Novartis, Sanofi, Pfizer, Merck. All other authors have declared no conflicts of interest.