Clinical Research Directory

Inclusion Criteria: * Aged 18 years or older, regardless of gender. * Able to understand and voluntarily sign a written informed consent form (ICF). * Confirmed recurrent or metastatic HNSCC that is not curable with local treatments. Primary tumor must be located in the oral cavity, oropharynx, hypopharynx, or larynx. * Able to provide well-preserved or fresh tumor tissue. * According to the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1, at least one measurable lesion confirmed by CT or MRI. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1. * Life expectancy ≥ 3 months. * Normal major organ function within 7 days prior to treatment. Exclusion Criteria: * Primary tumor located in the nasopharynx, nasal cavity, paranasal sinuses, salivary glands, thyroid or parathyroid glands, skin, or squamous cell carcinoma with an unknown primary site. * Presence of leptomeningeal metastasis, spinal cord compression, symptomatic or progressive brain metastases. * (Only for Stage 2 in Part 2) Prior systemic anti-tumor therapy for recurrent or metastatic HNSCC. * Known allergy to any component of SYS6002, JMT101, or Enlonstobart injection. * Participants who have previously received MMAE toxin ADC treatment (only for Part 1 and Stage 2 in Part 2). * Adverse events related to prior anti-tumor treatment that have not resolved to ≤ Grade 1 according to NCI-CTCAE v5.0 (except for toxicities deemed low-risk by the investigator, such as Grade 2 alopecia). * Washout period not met for anti-tumor medications or treatments. * Any serious and/or uncontrolled comorbid conditions that may interfere with the participant's ability to participate in the study * Pregnant or breastfeeding women; women of childbearing potential with a positive pregnancy test within 7 days before enrollment. Breastfeeding women may participate if they stop breastfeeding, but they cannot resume breastfeeding during the treatment and after the study ends. * Any male or female participants of childbearing potential who refuse to use highly effective contraception during the study and for 6 months after the last dose of study drug. * Unwilling or unable to comply with the study procedures and requirements, or deemed unsuitable for participation by the investigator.