Ranbaxy Laboratories is holding on to its high price of Rs 1089 for Cilanem, a new class of anti bacterial, despite Merck & Co, the original discoverer, launched its brand Zienam at a price of Rs 1221 in the Indian market last September.

Ranbaxy launched its product in 2003 and has been enjoying a monopoly with no competition even from Merck. As no other Indian company has attempted to launch the product so far, Ranbaxy has been able to maintain its price, although quality of the product is not comparable to that of Merck. The product is a high end anti-infective injectable for use against nosocomial and life-threatening infections.

While Merck maintains that the company's pricing is in tune with the international pricing structure for the now off patent Zienam, the high cost charged by a generic manufacturer is alleged to be an indicator of how future pricing of drugs would be in the absence of multiple generic players for the same compound.

The Ranbaxy product is a combination of imipenem with cilastatin, and belongs to the new class of antibacterials - the carbapenems. The company, quoting ORG had claimed the potential market size of the product in India to be approximately Rs 150 crore. The international market of the molecule two years ago was around USD 585 million.

Launching Zienam in September 2005, MSD India, the Indian arm of Merck & Co had described Zienam as a prescription drug used in the therapy of hospital bacterial infections and is indicated for prophylaxis as well as treatment. Imipenem, the key component of Zienam, makes the drug highly effective against pathogens of the gram-positive, gram-negative as well as aerobic and anaerobic spectra. Since the bactericidal activity of b-lactam antibiotics is broader than that of other antibiotic strains, Zienam is particularly indicated for the treatment of intra-abdominal infections, infections of the respiratory tract, gynecological and genitourinary infections, septicemia, skin and soft tissue infections, endocarditis and bone and joint infections, the company had noted. While both the drugs aim at the same target groups, there are conflicting claims about the stability of these medicines.

While Merck gives 24 month life time for every batch of Zienam, the expiry period of Cilanem is allegedly having batch-wise variations. Merck sources informed that since the launch of Zienam, doctors are fast switching over to the 'original' drug that has standard quality and efficacy. According to them, the number of institutions that are going for Zienam prescription are on the rise. Ranbaxy could not be contacted for comments.

Industry sources felt that the difficulty in maintaining uniform stability was the reason behind generic companies not showing interest in production of copy-cat versions of Zienam. The generic versions are not accepted in the developed world due to the same reason.

The industry sources are keenly watching if Ranbaxy announces a reduction in the price of Cilanem to retain the sales of its drug in domestic market.