US regulators have issued a complete response letter regarding Pfizer’s filing for a biosimilar version of Roche's blockbuster cancer drug Herceptin.

The US Food and Drug Administration has asked for more technical information, but this does not relate to safety or clinical data contained in the application, the drug giant stressed.

Further information was not disclosed, but Pfizer said it is now working closely with the FDA to address the contents of the letter and “remains committed to bringing this important medicine to patients in the US”.

Herceptin (trastuzumab) currently pulls in nearly $7 billion a year in sales from across its marketed indications in breast and gastric cancer.

Meanwhile, Pfizer also announced that Trumenba has been awarded a Breakthrough Therapy designation for active immunisation to prevent invasive disease caused by Neisseria meningitidis group B (MenB) in children ages one through nine years.

“Despite the occurrence of invasive serogroup B disease in children ages one through nine years, and the potential life-altering and long-term consequences that may result from this uncommon disease, there is no MenB vaccine licensed in the US for this age group,” said Dr Luis Jodar, chief medical and scientific affairs officer, Vaccines Medical Development, Scientific and Clinical Affairs, Pfizer.

“We look forward to working closely with the FDA toward our goal to extend the range of individuals who may benefit from immunization with TRUMENBA.”

Trumenba won traditional US approval in April last year for use in individuals 10 to 25 years of age for the three-dose schedule.