How would you treat a patient with metastatic neuroendocrine carcinoma of the gallbladder with early relapse after platinum doublet?

By describing the tumor as a Neuroendocrine carcinoma one implies that the tumor is poorly differentiated and high grade. This is often described as extra-pulmonary small cell lung cancer or high grade GI NEC. There are no standard second line regimens. Options are to treat similarly to a small cell...