The National Pharmacovigilance Advisory Committee (NPAC) has asked drug companies which licensed to manufacture and sell generics of Cox-2 inhibitor category drugs to submit additional data on the product safety with immediate effect. The move is a fall out of the reported ADRs and the subsequent withdrawal of rofecoxib, a cox-2 inhibitor drug, from the international markets including India.

Following the demand from the NPAC, the manufacturers of celecoxib, valdecoxib and parecoxib generics should initiate additional studies such as safety profile during use for more than 18 months, potential reactions of the drug in various dosage forms and designs etc. immediately and submit the data to the Committee in the stipulated time. According to informed sources, the Committee has left the data investigation to the companies as it would cost almost equivalent amount of the previous clinical trials conducted on these drugs.

The Committee, which recommended the recall of rofecoxib brands in India after the US-based Merck & Company withdrew its block-buster brand Vioxx from the international markets, has now demanded the additional safety data on other Cox-2 inhibitors from the manufacturers with a view that these products could also be as harmful as rofecoxib in prolonged use.

Though the industry had a vague notion that any ban on rofecoxib could lead to doubts on certain other Cox-2 inhibitors too, the NPAC move has really rocked the sector as further investigation for additional safety data could lead to further investment for clinical investigation and if the results are negative, it may cause another controversy and a possible recall of these drugs.

While Refecoxib and its brands constitute about 30 per cent of the market, the same category drugs like celecoxib and valdecoxib constitute 60 per cent of the Cox-2 Inhibitor category. At present, there are about 52 brands of valdecoxib exists in the Indian market and the total turnover is estimated to be Rs 90 crore (ORG-IMS data June 2004).

The major brands with crores of rupees business include Cipla's Valdixx and Cadilla Healthcare's Valedon brands. Besides, ten per cent of the same category belongs to Parecoxib and its brands. Cox-2 Inhibitor drugs have gained widespread acceptance in the recent times, especially due to the alleged side effects related to usage of nimesulide among children.

The industry sources are of the view that it was a difficult proposition at present to correctly estimate the volume and value of the rofecoxib, and similar generic brands floating in the Indian market.

Though the DCGI, after the recommendation from NPAC, is yet to notify the ban on rofecoxib, even almost all the manufacturers have restrained themselves from manufacturing the drug in India.

However, in the country, there does still prevail a complete lack of effective monitoring mechanisms and data management of drugs. Even the state and the central drug control administrations do not have exact data on the number of rofecoxib approvals and brands floating in the market. Apart from the information provided by the companies, which market these brands, no other data has been compiled by any of the monitoring agencies. The issue also becomes complex as rofecoxib and other Cox-2 inhibitor drugs are relatively new drugs. In this context, the NPAC move, asking for additional safety data for the other drugs, has been considered as a welcome trend.