FCN-159 in Adult Patients With Symptomatic, Inoperable Neurofibromatosis Type 1-Related Plexiform Neurofibromas

Inclusion Criteria: 1. ≥ 18 years old and ≤ 70 years old. 2. Patients must be diagnosed with symptomatic NF1-related plexiform neurofibromas (PNs) and require systemic therapy at the investigator's discretion. 3. Presence of measurable lesions, defined as ≥ 3 cm in length in at least one dimension, which can be evaluated for efficacy by MRI. 4. Karnofsky performance status score ≥ 70. 5. Patients with adequate organ and bone marrow functions. Exclusion Criteria: 1. NF1-related malignancies requiring chemotherapy, radiotherapy, or surgery, such as medium to high grade optic glioma or malignant peripheral nerve sheath tumor. 2. Patients with a history of or concurrently with other malignancies (excluding cured non-melanoma skin basal cell carcinoma, breast cancer in situ or cervical cancer in situ, and other malignancies without evidence of disease within 5 years). 3. Patients who cannot undergo MRI and/or have contraindications to MRI. 4. Patients with previous or current retinal vein obstruction (RVO), retinal pigment epithelial detachment (RPED), glaucoma, and other abnormal ophthalmic examination with clinical significance. 5. Interstitial pneumonia, including clinically significant radiation pneumonia. 6. Cardiac function or combined diseases meet one of the following conditions: 1. QTcF value of \> 470 milliseconds; patients with risk factors for QTcF prolongation or patients receiving drugs that prolong the QTcF interval. 2. Congestive heart failure per New York Heart Association (NYHA) classification ≥ Class 3. 3. Arrhythmias with clinical significance. 4. Known concurrent clinically significant coronary artery disease, cardiomyopathy, and severe valvular disease. 5. LVEF \< 50%. 6. Patients with a heart rate of \< 50 beats/min.