Halozyme Therapeutics, Inc., a biopharmaceutical company dedicated to developing and commercializing innovative products that advance patient care, has announced that the Center for Biologics Evaluation and Research (CBER) of the US Food and Drug Administration (FDA) has issued a complete response letter (CRL) for Baxter's HyQ Biologics License Application (BLA).

HyQ is an investigational product that includes plasma-derived Immune Globulin (IG) 10 per cent and Halozyme's recombinant human hyaluronidase (rHuPH20) for subcutaneous administration in patients with primary immunodeficiency disease.

The letter requested additional preclinical data to support the BLA. The primary issues raised in the letter focused on non-neutralizing antibodies generated against recombinant human hyaluronidase and the possible effects of these antibodies on reproduction, development and fertility. Elevated anti-rHuPH20 antibody titers were detected in the registration trial, but have not been associated with any adverse events.

Pending the parties providing additional preclinical data sufficient to address the regulatory questions, CBER has requested that patients should no longer be dosed with rHuPH20 in the Baxter and ViroPharma clinical studies.

Halozyme has been in contact with the Centre for Drug Evaluation and Research (CDER) regarding the impact on Hylenex recombinant (hyaluronidase human injection). CDER is the division of FDA regulating the other investigational rHuPH20 programs, including insulin and PEGPH20. After reviewing the data, CDER has confirmed that there is no need for actions against Hylenex or clinical programmes in the Hylenex IND.

"With receipt of the CRL, we can directly address the questions raised by CBER," said Gregory I Frost, PhD, president and chief executive officer, Halozyme. "We look forward to collaborating with the agency to address their concerns."