Role of Somatostatin Analogs for Patients With pNETs

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Somatostatin analogs, which have historically been used to control hormone symptoms, recently demonstrated antiproliferative activity for patients with neuroendocrine tumors, states Matthew H. Kulke, MD. This activity was demonstrated in two randomized, placebo-controlled clinical studies that showed the efficacy of somatostatin analogs in slowing tumor growth.

The first was the PROMID study, which compared octreotide long-acting repeatable 30 mg to placebo in patients with a midgut carcinoid tumor. Jonathan R. Strosberg, MD, noted that the primary endpoint result of time to tumor progression was 14.5 months with octreotide and 6 months with placebo, confirming that octreotide can inhibit tumor growth.

The second study, labeled CLARINET, compared the somatostatin analog lanreotide with placebo in approximately 200 patients with either midgut or pancreatic neuroendocrine tumors (pNETs), Diane Reidy Lagunes, MD, MS, explains. The primary outcome measure of progression-free survival (PFS) was not reached in the lanreotide arm compared with a median of 18 months for placebo.

Rodney F. Pommier, MD, suggests that most oncologists have already been using somatostatin analogs in their patients with pNETs for their antiproliferative affects, particularly for patients with VIPomas, glucagonomas, and metastatic gastrinomas. The trial data validated what oncologists have already been doing, he added.

The slow growth rate observed in the clinical trials suggests that watchful waiting may be a viable option in patients with pNETs, Lagunes believes. The panel agreed that factors such as the patient’s age and comorbidities, the growth rate of the tumor, and whether the patient is symptomatic should be considered when making decisions regarding therapy initiation.