This study is for subjects that have relapsed or refractory follicular lymphoma, which means your lymphoma has worsened after treatment or has not responded to treatment. This study is testing an "investigational" (not yet FDA approved drug) study drug called loncastuximab tesirine (ADCT-402). Treatment will be administered intravenously or via tablet depending on the subject's assigned treatment. The primary purpose of this study is to test whether the investigational drug called loncastuximab tesirine may be more effective treatment for relapsed or refractory follicular lymphoma than treatment with the drug idelalisib. The subject will be seen approximately once every three weeks, and may remain in the study for up to 3 years.

This study is for subjects that have been diagnosed with peripheral T-cell lymphoma (PTCL) and have received at least one prior systemic therapy for their disease. This study is testing an "investigational" (not yet FDA approved drug) study drug called Lacutamab (IPH4102). The primary purpose of this study is to evaluate the safety and effectiveness of lacutamab. The subject may remain in the study until their disease progresses or they have developed unacceptable toxicity secondary to lacutamab and can expect to be in follow-up for 1 year if they discontinue treatment in the first year.