Carcinoid Tumor Diversity

Carcinoid tumors are a diverse group of tumors that arise from the diffuse neuroendocrine system and occur most commonly in the gastrointestinal tract.1 The clinical presentations of these tumors depend on their site of origin and the bioactive substances secreted if any.1 It is estimated that as many as 40 different substance may be secreted by carcinoid tumors.2

Current Surgical and Medical Options
First-line treatment for carcinoid tumors is surgery; however, these tumors are often metastatic when finally diagnosed and curative resection is not always possible.1 In addition, the clinical profile of current somatostatin analogs is somewhat limited:1,3

    * Symptomatic control (median: 60% of patients)
    * Biochemical control (median: 70% of patients)
    * Tumor response is minimal (median: ~ 8% of patients)
    * Median duration of response of about 1 year (hormone control and limiting tumor growth)
    * Bind with high affinity to only 1 of the 5 somatostatin receptors3  

Carcinoid Tumor Diversity
Multireceptor Targeting and the Potential for Improved Outcomes

The goals of treatment for carcinoid tumors include achieving:1,3
    * Symptom control
    * Biochemical control
    * Tumor control
    * Improved quality of life
    * Prolonged survival

Current somatostatin analogs may initially be effective for symptom and biochemical control, but tumor regression is rare and the median duration of symptomatic response and control of tumor growth is limited to approximately 12 months.2,3

In vitro studies have demonstrated that multiple somatostatin receptors regulate cellular pathways controlling secretion, a potentially important action for symptom and biochemical control.4

The goals in rationally designing a multireceptor-targeting somatostatin analog were aimed at achieving greater antisecretory activity and improved antitumor activity.5

Pasireotide in Carcinoid Syndrome: A Phase II Study
Animal and phase II and II human studies have demonstrated the antisecretory and antitumor effects of pasireotide.6-8 In a Phase II clinical trial of patients with metastatic carcinoid tumors, who were inadequately controlled by octreotide LAR, 27% of the patients achieved full or partial symptom control (diarrhea and/or flushing) with pasireotide.