Generic name: Linezolid

Brand name: Zyvox and Zyvoxid

Cost in South Africa: R282.25 per 600 mg tablet in the public sector and R593.01 per 600 mg tablet in the private sector (SEP ex VAT)

Linezolid is used in the treatment of drug resistant tuberculosis (TB) and other serious infections. It is recommended to treat complicated cases of drug resistant TB, for patients failing other medicines. However use of the medicine, particularly in the public sector, is extremely limited because of the high cost of the medicine.

Linezolid, which is usually taken once or twice daily over many months (the optimal dosage for DR-TB treatment has not yet been established) costs R282 for a single 600 mg tablet in the public sector[1] and R593 for a single 600 mg tablet in the private sector[2]. Linezolid is marketed by Pfizer in South Africa – no generic versions are available in the country.

Generic versions of Linezolid are currently available in countries where Pfizer does not have a patent. Generic equivalents are available in India at only R13 per tablet (FDC Limited. Sandoz and Cipla).[3] Four generic suppliers (Teva, Mylan, Glenmark and Gate Pharma) have received tentative FDA approval to enter the US market when the Pfizer patent expires.[4]

In South Africa the basic patent claiming Linezolid was first filed in South Africa by Upjohn Company – now owned by Pfizer. It is expected to expire in 2014. Additionally Pfizer filed for a process patent in 2008 and a product patent on the Crystal Form II in 2002. A formulation patent was filed in 2002 by Pharmacia and Upjohn Company.[i]

The legal situation in South Africa remains unclear. The younger Crystal Form II and formulation patents might block the entry of generic versions of the medicine even after the initial patent expires in 2014.

Applying for a patent on a new formulation of an already existing medicine is a tactic commonly used by pharmaceutical companies to retain their patent monopoly after the expiry of their initial 20 year patent period. This tactic is referred to as ‘ever-greening’. By amending its law, South Africa could prevent the ever-greening of medicine patents by heightening the standards of patentability to exclude new forms and formulations of existing medicines from patentability.

Further South Africa could issue a compulsory license to access lower cost generic versions of the medicine, while the patent remains. South Africa should use the flexibilities available under TRIPS to access affordable medicines.