Phase II trial of single agent Val-boroPro (Talabostat) inhibiting Fibroblast Activation Protein in patients with metastatic colorectal cancer.

Publication/Presentation Date

11-1-2007

Abstract

PURPOSE: Fibroblast Activation Protein (FAP) is a tumor fibroblast protease that has been shown to potentiate colorectal cancer growth. The clinical impact of FAP inhibition was tested using Val-boroPro (Talabostat), the first clinical inhibitor of FAP enzymatic activity, in a phase II study of patients with metastatic colorectal cancer.

METHODS: Patients with metastatic colorectal cancer who had previously received systemic chemotherapies were treated with single agent Val-boroPro 200 microg p.o. BID continuously. Eligibility included measurable disease, performance status of 0 to 2, and adequate organ function. Laboratory correlates evaluated the pharmacodynamic effects of Val-boroPro on FAP enzymatic function in the peripheral blood.

RESULTS: Twenty-eight patients (median age 62; 12 males, 16 females) were enrolled in this study. There were no objective responses. Six of 28 (21%) patients had stable disease for a median of 25 weeks (range 11-38 weeks). Laboratory analysis demonstrated significant, although incomplete inhibition of FAP enzymatic activity in the peripheral blood.

CONCLUSION: This phase II trial of Val-boroPro demonstrated minimal clinical activity in patients with previously treated metastatic colorectal cancer. However it provides the initial proof-of-concept that physiologic inhibition of FAP activity can be accomplished in patients with colorectal cancer, and lays the groundwork for future studies targeting the tumor stroma.

Volume

6

Issue

11

First Page

1691

Last Page

1699

ISSN

1555-8576

Disciplines

Medicine and Health Sciences

PubMedID

18032930

Department(s)

Hematology-Medical Oncology Division

Document Type

Article

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