This study involves taking a study drug called Lutetium Lu 177 Edotreotide. The overall goal of this study is to see if the study drug is safe in adolescent subjects with a SomatoSTatin Receptor positive (SSTR-positive) solid tumor or lymphoma that is recurrent or that has progressed under one or more previous treatments, and which cannot be completely removed by surgery.

This study enrolls patients with refractory, progressive, or relapsed solid tumors. The purpose of this study is to find out whether a drug called PEEL-224 ("the study drug") is safe and effective when given as monotherapy (a drug given by itself) and as part of a combination therapy together with other chemotherapy drugs.