How many compound names list a chemical class of depsipeptide and a clinical trials β value of 1/7?
create table table_12715053_1 (compound_name varchar, chemical_class varchar, clinical_trials_β varchar, PRIMARY KEY (compound_name))
select count(compound_name) from table_12715053_1 where chemical_class = "depsipeptide" and clinical_trials_β = "1/7"