Prevacid NapraPAC Script Growth Suggests PPIs Do Well After Vioxx

TAP's Prevacid NapraPAC is among the early winners in the arthritis market following the withdrawal of Merck's Vioxx , IMS Health data suggest.

The co-packaged version of TAP's proton pump inhibitor Prevacid (lansoprazole) with the generic non-steroidal anti-inflammatory drug naproxen saw scripts jump 33%, from a monthly base of about 12,000 to 16,000 in October. TAP launched the product in January (¹ , p. 33).

Although the script totals for Prevacid NapraPAC are relatively small, they likely reflect the tip of the iceberg for PPI use in combination with older NSAIDs as a strategy for managing gastro-intestinal risks.

IMS Health data indicate that prescriptions dispensed for generic arthritis drugs (including prescription-strength ibuprofen, naproxen and all other NSAIDs) increased by 13% in October to 5.6 mil.

Since most of the growth presumably came from patients switched off of Vioxx or one of the other COX-2 inhibitors, physicians may also have prescribed a PPI to manage the GI risk.

At the time of the withdrawal, Prevacid was the only PPI with an approved indication for reducing the risk of NSAID-induced ulcers.

However, AstraZeneca's Nexium (esomeprazole) added that claim Nov. 24, when FDA approved a supplemental NDA "for the reduction in the occurrence of gastric ulcers associated with continuous NSAID therapy in patients at risk for developing gastric ulcers." AstraZeneca plans to begin detailing the new indication "very soon," the company said.

The supplemental indication for Nexium was based on two placebo-controlled studies in 1,429 patients.

The study design allowed background use of either a non-selective NSAID or a COX-2 selective NSAID. The results were analyzed across both types of therapy; labeling does not distinguish ulcer rates in COX-2 patients.

"Patients receiving NSAIDs and treated with Nexium 20 mg or 40 mg once a day experienced significant reduction in gastric ulcer occurrences relative to placebo treatment at 26 weeks," labeling states. "No additional benefit was seen with Nexium 40 mg over Nexium 20 mg."

"These studies did not demonstrate significant reduction in the development of NSAID-associated duodenal ulcer due to the low incidence."

In the studies, 94.7% to 95.4% of patients receiving Nexium 20 mg and 95.3% to 96.7% of patients receiving Nexium 40 mg remained ulcer-free at 26 weeks, compared with 83.3% to 88.2% on placebo, the updated labeling states.

PPI marketers could be the main commercial challenge facing Pfizer in the arthritis category if the company is successful in defending the continued marketing of its COX-2s Celebrex and Bextra .

Pfizer reported Nov. 30 that its share of the total arthritis market increased by eight percentage points in the month following the Vioxx withdrawal, from 33% to 41%. The company declared its confidence that Celebrex will emerge from the current period of adverse publicity and regulatory uncertainty as the "big winner".

The IMS data do include one potentially troubling signal for Pfizer going forward: Bextra, not Celebrex, was the immediate "winner" in the aftermath of the Vioxx withdrawal.

Bextra scripts jumped 29% in October, to 1.5 mil., while Celebrex scripts posted a smaller but still strong 17% increase to 2.3 mil.

The data suggest that physicians were more likely to switch Vioxx users to Bextra than to Celebrex - perhaps because Bextra is newer and therefore less likely to have been tried previously by Vioxx patients.

However, Pfizer added a "black box" warning to Bextra regarding serious skin reactions, and appears to face a bigger challenge in demonstrating the cardiovascular safety of that brand compared to Celebrex.

Another Pfizer brand quietly gained ground after Vioxx: Arthrotec , which combines the NSAID diclofenac with the GI protective agent misoprostol saw prescriptions increase by 18% to 223,000.