FDA Lifts Hold on Start of Helix’ Trial for Topical Treatment for Cervical Lesions

FDA has lifted a clinical hold preventing Helix BioiPharma from starting a Phase II/III study evaluating its topical interferon alpha-2b product in the treatment of low cervical intraepithelial neoplasia. The agency’s go-ahead for the trial followed a review of the firm’s complete response submission to the hold, which it filed in mid October. However, Ontario-based Helix says it doesn’t have the financial resources to continue development of the product on its own, and will need to find a strategic partner both the pivotal U.S. study, and a planned Phase III European study can be initiated.

Helix’ topical interferon alpha-2b candidate is formulated using the firm’s Biphasix™ platform to encapsulate the drug in biphasic lipid vesicles. The planned double-blind vehicle-controlled study in the U.S. aims to evaluate treatment using topical interferon alpha-2b in about 492 premenopausal women with histologically confirmed CIN 1 or CIN 2 lesions and high-risk HPV infection.

Enrolled patients will self-administer either topical interferon alpha-2b or control using a vaginal applicator, over a 10–14 week period. The proposed primary endpoint will be the resolution of CIN 1 or CIN 2 lesions at month 12, with assessments including colposcopic-directed cervical biopsy and Pap smear cytology to evaluate both endocervical and ectocervical tissues.

Helix is separately developing a urease-derived anticancer candidate, L-DOS47, which is designed to reverse the body’s natural ammonia-urea conversion process specifically at the site of tumors. The drug’s action essentially generates ammonia and hydroxyl ions from nontoxic urea, leading to increased pH in the tumor microenvironment, and resulting in directly toxic effects. Tumor targeting is effected by combining the urease compound with a tumor-targeting antibody. While the firm expects the DOS47 platform technology will have applications against a range of tumor types, the initial product, L-DOS47, is designed to target non-small cell lung cancer.

Regulatory approvals have been granted to start a European Phase I/II study with L-DOS47, and a U.S. Phase I trial. In its recently reported results for fiscal 2011, Helix said both trials are expected to start during the next 12 months or so.