**Core Concept**
Mogamulizumab is a monoclonal antibody that targets the CCR4 receptor, a chemokine receptor involved in the trafficking of immune cells, particularly T cells. Its mechanism of action is based on the depletion of CCR4-positive T cells, which play a crucial role in the pathogenesis of certain types of cancer.

**Why the Correct Answer is Right**
Mogamulizumab was approved by the FDA for the treatment of relapsed or refractory Sézary syndrome, a type of cutaneous T-cell lymphoma. The drug works by binding to the CCR4 receptor on the surface of T cells, leading to their depletion through mechanisms such as antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. This results in a reduction in the number of malignant T cells in the body, thereby improving symptoms and slowing disease progression.

**Why Each Wrong Option is Incorrect**
**Option A:** Mogamulizumab has not been approved for the treatment of multiple myeloma, a type of blood cancer characterized by the proliferation of malignant plasma cells.
**Option B:** While mogamulizumab targets the CCR4 receptor, it is not used for the treatment of autoimmune disorders such as rheumatoid arthritis, which involves a different set of immune cells and pathways.
**Option C:** Mogamulizumab is not indicated for the treatment of non-Hodgkin lymphoma, a type of cancer that arises from the lymphocytes, but has a different molecular pathogenesis.

**Clinical Pearl / High-Yield Fact**
Mogamulizumab is an example of a monoclonal antibody that targets a specific immune cell receptor, highlighting the importance of understanding the molecular mechanisms underlying cancer pathogenesis.

**Correct Answer:** C.