MORNINGLYTE: international, multicenter phase III study to evaluate the efficacy and tolerability of mosunetuzumab in combination with lenalidomide compared to standard treatment in patients with previously untreated follicular lymphoma.

In this study, we intend to evaluate the efficacy and tolerability of the combination of mosunetuzumab-lenalidomide (experimental treatment) compared to a standard immunochemotherapeutic treatment (standard treatment). Allocation of treatment between the experimental and standard treatment will be done by randomization. Prior to randomization, the investigator will inform the patient which standard treatment he/she considers most appropriate (i.e. the regimen he/she would suggest outside the trial). Each group will receive a different treatment: - Experimental treatment: These patients will receive the mosunetuzumab-lenalidomide combination. - Standard treatment: these patients will receive a treatment chosen by the doctor from four standard immunochemotherapy regimens, depending on what he considers most appropriate. After completion of treatment, patients will continue to come for visits and additional examinations every 3 months for 2 years. Then every 6 months for 3 years. Then annually for up to 7 years after the last patient is enrolled in the study (i.e. between 4.5 and 7.5 years).

(BASEC)