This study is about testing if a new treatment is safe and works for people with head and neck cancer. The treatment includes **Ad/PNP** and **Fludarabine Phosphate (F-araAMP)**. **Ad/PNP** is a special virus that doesn't copy itself, and it's put directly into the tumor. Then, **F-araAMP** is given through a vein. Together, they make a chemical in the tumor to help fight cancer.

The study checks if this treatment is safe when given multiple times and if it helps shrink tumors. People who join will get the treatment every 4 weeks for up to 5 cycles. Doctors will watch closely for any side effects or improvements in the cancer.

• This study lasts several months, with treatments every 4 weeks for up to 5 cycles.
• Participants must visit the clinic for injections and monitoring.
• It's important to talk to your doctor about the possible risks and benefits.

You can join if you’re 18 or older, have certain types of head/neck cancer, and meet other health conditions. Pregnant women or those with certain health issues can't join. If you’re interested, make sure to discuss with your healthcare provider.