BETHESDA, MD 30 August 2012—FDA on August 29 announced the approval of tbo-filgrastim to stimulate neutrophil production in adults who become neutropenic while undergoing chemotherapy for nonmyeloid cancers.

Teva Pharmaceutical Industries Ltd. today announced that it does not expect to market tbo-filgrastim in the United States until November 2013 at the earliest. The product will be sold under the brand name Neutroval.

According to Teva, tbo-filgrastim is sold as Tevagrastim in the European Union, where the product is classified as biosimilar to Amgen's recombinant human granulocyte colony-stimulating factor (G-CSF) product, Neupogen.

FDA was directed in 2010 to create an abbreviated mechanism for approving biological products that are shown to be biosimilar or interchangeable with another FDA-licensed biological product.

A section of FDA's website provides information about the agency's progress toward an approval process for these drugs, including a draft guidance document for manufacturers. But the biosimilar approval process has not yet been finalized.

Teva thus obtained FDA's approval of tbo-filgrastim through the standard application process for new drugs and certain biological products.

According to the FDA-approved labeling (PDF) for tbo-filgrastim, the drug is a short-acting recombinant G-CSF product.

The recommended dosage of tbo-filgrastim is 5 µg per kg of patient weight per day injected subcutaneously, with the injection site alternating among several recommended in the labeling. The initial dose should be administered no earlier than 24 hours after the myelosuppressive chemotherapy session but not within 24 hours of the next scheduled chemotherapy session.

The labeling recommends that daily treatments with tbo-filgrastim continue until the patient's neutrophil level has recovered to within the normal range. Monitoring of the patient's complete blood count should occur before chemotherapy and twice weekly until the neutrophil level recovers.

In clinical trials, bone pain was the most frequently reported adverse event reported by patients treated with tbo-filgrastim.

Rare but serious adverse events that are associated with the use of human G-CSF products include splenic rupture, acute respiratory distress syndrome, sickle cell crisis, and hypersensitivity reactions.

Tbo-filgrastim will be supplied in packs of 1, 5, or 10 prefilled single-use syringes for s.c. injection that contain 300 µg of tbo-filgrastim in 0.5 mL of solution or 480 µg in 0.8 mL.

The prefilled syringes should be refrigerated at 2–8° C and protected from light until use. A syringe may be removed from refrigeration and stored at 23–27° C for a single five-day period. If not used within that period, the syringe may be refrigerated again until its expiration date.