The withdrawal of Bayer's cholesterol agent Baycol may help Pharmacia in its efforts to differentiate Celebrex from Vioxx in the COX-2 inhibitor class, Global Prescription Business President Carrie Cox suggested during the Bear Stearns "virtual" healthcare conference Sept. 26.

"It is not surprising to find out that different agents in the same category have different profiles," Cox said. "People have had that reminded to them recently with the events surrounding Baycol." Bayer withdrew cerivastatin in August due to a higher rate of reports of rhabdomyolysis than other agents in its class (¹ Also see "Baycol Withdrawal Gives Boost To Pravachol; Will Crestor NDA Be Affected?" - Pink Sheet, 13 August, 2001.).

Pharmacia maintains that Celebrex (celecoxib) has a safer cardiovascular profile than Merck's Vioxx (rofecoxib).

During the Bear Stearns conference, Cox acknowledged that COX-2 scripts are being impacted by the media attention surrounding an Aug. 22 Journal of the American Medical Association article citing a potential COX-2 class cardiovascular safety problem.

Cox criticized the meta-analysis, stating that while the article "got a lot of media coverage," it was "not based on new data, and did not in fact implicate Celebrex, while [there were] some negative events for Vioxx."

"It has been a little disappointing to see how many people have confused these two products, assuming that because they are in the same category, they must have the same profile," Cox added.

FDA's warning letter to Merck over Vioxx promotions gives "credibility and credence" to Pharmacia's claims, Cox declared. The letter "appears to validate what we have been saying for some time, which is that there may in fact be a cardiovascular risk with Vioxx, but that there does not seem to be one with Celebrex."

FDA's Sept. 17 letter objects to Merck's "hypothetical explanation" of the increased cardiovascular events associated with Vioxx in the VIGOR study (² Also see "Merck Vioxx Warning Letter Could Be Incentive For Large Cardio Safety Study" - Pink Sheet, 1 October, 2001.).

Cox speculated that FDA may be considering adding a cardiovascular warning statement to Vioxx labeling. "It will be interesting to see if FDA moves forward with cardiovascular language specific to Vioxx," she said. "It seems to have been reaffirmed [by the letter] that FDA does have some concerns in some way."

"I would reiterate that we are not aware of any concerns that FDA has about Celebrex and its cardiovascular risk points," Cox added.

Pharmacia does not appear optimistic about adding a COX-2 gastrointestinal safety superiority claim to labeling any time soon. Pharmacia and Merck's GI safety supplements were deemed "approvable" by FDA in April (³ Also see "COX-2 inhibitor safety labels" - Pink Sheet, 16 April, 2001.).

"There is no specific clock that we're aware of that is governing those reviews at this point in time," Cox said.

However, she maintained, "it almost doesn't make a difference what the labeling says anymore with regards to the GI benefits of these products, because the promise of the COX-2s in terms of their superior safety profile for GI tolerability has been well-established in the marketplace."

While Pharmacia will continue to try to differentiate Celebrex within the COX-2 class, "the challenge for all of us is to make sure that the business continues to move into the COX-2s, into Celebrex - not into other NSAIDs - while there is a temporary dip...in the marketplace," Cox said.

Merck gave the first warning of tempered COX-2 growth prior to the close of the second quarter, cautioning analysts that the new class was showing a slower rate of penetration versus older NSAIDs than expected (⁴ Also see "Merck Vioxx Sales Will Fall Short Of High Expectations, Firm Says" - Pink Sheet, 25 June, 2001.).

In July, Pharmacia CEO Fred Hassan acknowledged a slowdown in Celebrex' scripts, but maintained that the growth curve was "typical" of NSAIDs in their third year on the market (⁵ Also see "Celebrex Growth Is "Typical" Of NSAIDs After Three Years, Pharmacia Says" - Pink Sheet, 30 July, 2001.).

According to recent share numbers, "the lead that Vioxx had taken in the new prescription arena has essentially evaporated," Cox said. Vioxx lost its two-point lead on Celebrex in late August, leaving both products with essentially a 50% share, IMS data show.

COX-2 Safety Concerns Are Affecting Celebrex, Pharmacia Says

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