This study looks at how well two drugs, Lenalidomide and Daratumumab/rHuPH20, work after a specific medical procedure called an Autologous Stem Cell Transplant (ASCT) for patients with Multiple Myeloma (MM). MM is a type of blood cancer that affects plasma cells in the bone marrow. After ASCT, some patients will take just Lenalidomide, while others will take both drugs. The study will last up to 7 years with follow-ups for 15 years. Researchers will use a test called Minimal Residual Disease (MRD) to decide if patients should continue treatment. MRD checks for remaining cancer cells that can't be seen in regular tests.

• Study Duration: Up to 7 years with follow-ups for up to 15 years.
• Key Requirements: Must have had ASCT and be between 18 and 75 years old.
• Study Drugs: Lenalidomide alone or with Daratumumab/rHuPH20.

This study aims to find the best treatment length for keeping Multiple Myeloma away after ASCT. Participants must be able to take oral medication and have no serious medical issues. Participation is voluntary, and patients must sign a consent form. Please consult with your doctor to see if this study is right for you.