To explore the Objective Response Rate (ORR) of Benmelstobart combined with Anlotinib and chemotherapy as first-line treatment for large-cell neuroendocrine carcinoma of the lung (LCNEC) and extrapulmonary neuroendocrine carcinoma (EP-NEC)
Histologically or cytologically confirmed metastatic LCNEC or EP-NEC (per AJCC 9th Edition);
No prior systemic treatment for locally advanced or metastatic LCNEC or EP-NEC; For patients who have received adjuvant chemo/radiotherapy, neoadjuvant chemo/radiotherapy for non-metastatic disease with curative intent, or definitive chemoradiotherapy for locally advanced disease, the interval from the end of chemotherapy, radiotherapy, or chemoradiotherapy to the diagnosis of metastatic NEC must be at least 6 months (calculated from the end date of the last chemotherapy cycle or the end date of the last radiotherapy);
At least one measurable lesion according to the Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1; Lesions that have received prior radiotherapy can be considered measurable only if there is clear progression after radiotherapy and they are not the only lesion;
Aged 18-75 years;
Patients with brain metastasis and/or carcinomatous meningitis (excluding asymptomatic patients or patients with stable condition who have no imaging evidence of new/enlarged central nervous system metastasis for at least 2 weeks after brain metastasis treatment and have discontinued steroids or anticonvulsants for at least 14 days before the study; If active or new untreated asymptomatic central nervous system metastasis is detected during the screening phase, subjects must receive radiotherapy, or have no imaging evidence of new/enlarged brain metastasis for at least 2 weeks without treatment);
Prior use of anti-angiogenic drugs such as Anlotinib, Apatinib, Bevacizumab, or immunotherapeutic drugs targeting PD-1, PD-L1, etc.;
History of other malignant tumors within 5 years (except cured carcinoma in situ of the cervix or basal cell carcinoma of the skin);
Factors affecting oral drug administration (dysphagia, post-gastrointestinal resection, chronic diarrhea, intestinal obstruction, etc.);