Cetuximab (EGFR inhibitor)

The goal of this study is to understand whether CRB-701, a targeted form of chemotherapy called an anti-body drug conjugate, will work as a treatment for oropharyngeal (throat, tonsil) cancer. In patients who have already received platinum based chemotherapy or immunotherapy (using a check-point inhibitor) It will also learn about the safety of the drug and measure quality of life. The main questions it asks are: * What proportion of participants respond to CRB-701 measured using scans (CT or MRI) * What medical problems do participants experience when taking CRB-701. Researchers will compare CRB-701 with standard of care medicines (drugs that are normally used this disease). Participants will: * Attend clinic every three weeks to receive infusions of CRB-701 or standard of care medicines until the cancer cannot be measured or is not controlled by the treatment they are receiving. * Have a CT or MRI every 6 weeks to measure the effect on their cancer * Complete questionnaires to assess their health status.

This is a Phase I/II, single-arm, open-label, multi-center study to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of HSK42360-Na tablets combined with cetuximab with or without chemotherapy in patients with BRAF V600-mutant metastatic colorectal cancer (mCRC). The Phase I stage uses a 3+3 dose escalation design to determine the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) of HSK42360-Na in combination with cetuximab. The Phase II stage evaluates the efficacy and safety of HSK42360-Na combined with cetuximab alone or with mFOLFOX6/FOLFIRI chemotherapy in expansion cohorts.