Systematic literature review of the antitumor effect of octreotide in neuroendocrine tumors

Real-World Clinical and Patient-Reported Outcomes from the Longitudinal Telotristat Ethyl Treatment Registry of Patients with Neuroendocrine Tumors

Background

Telotristat ethyl (TE) is an oral tryptophan hydroxylase inhibitor approved for the treatment of carcinoid syndrome diarrhea (CSD) in combination with somatostatin analogs (SSAs).

Methods

This prospective, observational, single-arm study evaluated long-term patient-reported outcomes for adults initiating TE in US clinical practice from 2017 through January 2022. The primary objective was satisfaction with overall CS symptom control 6 months after initiating TE. Secondary objectives evaluated satisfaction with control of CSD, flushing, and CS symptoms, as well as work productivity/activity impairment, SSA use, and weight. All analyses were descriptive in nature.

Results

A total of 223 patients completed the baseline survey; 56% also completed the 6-month follow-up survey. Mean age was 61 years and 61% were women. After 6 months of TE treatment, the majority of patients (76%, n=95/125) reported being satisfied with control of their CS symptoms which was markedly improved from baseline (41%, n=91). Similarly, the majority of patients (78%, n=97/125) were satisfied with control of their CSD after 6 months of TE, markedly improved from baseline (36%).

Conclusion

This longitudinal observational study showed improvements in real-world clinical and humanistic outcomes for patients with CS and at least 6 months of TE treatment.

Antiproliferative Effects of Telotristat Ethyl in Patients with Neuroendocrine Tumors: The TELEACE Real-World Chart Review Study

Purpose

Neuroendocrine tumors (NETs) associated with carcinoid syndrome (CS) overproduce serotonin, mediated by tryptophan hydroxylase-1 (TPH1). The TPH inhibitor telotristat ethyl (TE) reduces peripheral serotonin and relieves CS symptoms. We conducted a real-world clinical practice study to explore the effects of TE on tumor growth in patients with NETs and CS.

Patients and Methods

Single-arm, pre/post chart review study of patients with advanced NETs who received TE for ≥6 months and had ≥2 radiological scans within 12 months before and ≥1 scan after TE initiation. Linear regression and longitudinal analyses assessed changes in tumor size controlling for background NET treatment.

Results

Two hundred patients were enrolled, most (61%) had well-differentiated gastrointestinal NETs (61%) and received TE for an average of 12 months (SD, 7.3). Mean reduction in tumor size after TE initiation was 0.59 cm (p=0.006). Longitudinal analysis showed an 8.5% reduction in tumor size (p=0.045) from pre- to post-TE periods. Documented NET treatment prior to initiating TE and time between scans were not significant predictors of changes in tumor size. Results were consistent in a subgroup of patients with the same documented NET treatment before and after initiating TE.

Conclusion

TE may have antitumor effects consistent with serotonin overproduction in tumor growth.