That study was from 2022. Avenge Bio the company that was founded to run trials for their drug (AVB-001) has been shut down. They did start a phase1/2 trial in January 2023 and the drug was fast tracked by the FDA but that trial was terminated. The drug AVB-001 induces a high level of IL-2 (downregulated by leronlimab) production in a localized environment.

I can see two possible reasons for it's failure. IL-2 promotes a high inflammatory environment which might have led to serious adverse events. AVB-001 could have also failed to be effective. IL-2 would increase tumor fighting T-cell counts but it would also greatly increase Treg (T regulatory) cell counts. Those Tregs would keep the tumor fighting T-cells from killing the tumor. Downregulating IL-2 has been shown to reduce tumor growth. So it's a bit counter-intuitive to increase IL-2 unless you also downregulate Tregs. Leronlimab increases tumor fighting T-cells while also downregulating Tregs taking care of both problems.