Phase II study of thalidomide in patients with metastatic carcinoid and islet cell tumors

Carcinoid and islet cell tumors are known to be highly vascular. There is no effective systemic therapy currently available for metastatic disease. We conducted a phase II trial to evaluate the efficacy of the anti-antiangiogenic agent thalidomide in metastatic neuroendocrine tumors.

Eighteen patients with measurable, histologically proven metastatic carcinoid neuroendocrine carcinomas (well-differentiated, n = 13; moderately-differentiated, n = 5) were enrolled on this study. The majority of the patients had gastrointestinal primaries (small bowel, 8; pancreas, 5; colon, 1). All but one patient had hepatic metastases, and 12 patients (67%) had carcinoid syndrome. All patients had Eastern Cooperative Oncology Group performance status of zero or one. Eight patients (44%) had received previous hepatic artery chemoembolization and 11 (61%) had undergone surgical resection. Patients were started on oral thalidomide at a daily dose of 200 mg that was escalated to the target dose of 400 mg daily after 2 weeks. Tumor response was assessed at 12-week intervals using RECIST criteria. Planned treatment duration was 24 weeks unless unacceptable toxicity or disease progression was observed.

No patient achieved a partial remission or a complete remission. Best response was stable disease (SD) in 11 of 16 response-evaluable patients (69%). Serum pancreastatin results did not correlate with clinical response. Grade 3 toxicities included dizziness with orthostatic hypotension (n = 5), sensory neuropathy (n = 2), fatigue (n = 2), hemorrhagic cystitis (n = 1), and deep venous thrombosis (n = 1). Frequent Grade 1–2 toxicities were: fatigue (n = 13), constipation (n = 13), dry mouth (n = 12), somnolence (n = 12), dizziness/syncope (n = 10), weight gain (n = 5), and peripheral neuropathy (n = 5).

Thalidomide was fairly well tolerated in patients with metastatic carcinoid/islet cell tumors, but failed to reveal any objective responses. The single stage design of the trial makes it difficult to determine whether observed SD in a subset of patients was attributable to the indolent nature of these tumors, or to beneficial effect of thalidomide.