Study Overview: This study is testing a new medicine called AV-380 for cancer patients who have cachexia, a condition where people lose weight and muscle even if they eat. The study will check how safe the medicine is and how it works in the body. AV-380 is a special protein called a monoclonal antibody that targets something in the body known as GDF-15, which is linked to cachexia.

Eligibility: To join, you must be 18 or older, have a confirmed solid tumor cancer, and be losing weight. You shouldn't have severe heart problems recently, brain issues not treated yet, or be fed through a tube. You also can't join if your weight loss is due to other diseases like severe lung disease or heart failure.

• **Study Length:** You need a life expectancy of at least 3 months.
• **Visits:** Regular doctor visits are needed to monitor your health.
• **Risks:** If allergic to proteins like monoclonal antibodies, this study isn't for you.

Note: This study involves taking an experimental medicine, which means it could have unknown risks.