This Tuesday will see Bristol-Myers Squibb’s new rheumatoid arthritis therapy Orencia (abatacept) in front of a US Food and Drug Administration advisory panel and an agency briefing paper published before the hearing suggests that B-MS could be in for some mixed news.

The paper notes agrees with B-MS that Orencia, which is a selective T-cell co-stimulation modulator, “demonstrated effects on signs and symptoms of RA, including major clinical response, inhibition of structural damage, and improvement in physical function.” However, the firm will likely need to submit an additional year of efficacy data to get approval for the physical function claim for the drug.

The document also notes: “Combination use will likely be an issue for committee discussion.” In particular, it will have to consider the increased risk of infection when Orencia is administered concomitantly with biologic RA therapies such as the anti-tumour necrosis factor agents - Abbott Labs’ Humira (adalimumab), Amgen/Wyeth’s Enbrel (etanercept), Johnson & Johnson’s Remicade (infliximab) and Amgen’s Kineret (anakinra).

This fear stems from recent data relating to a Phase III ASSURE study, which showed a higher incidence of serious infections for Orencia versus placebo. The FDA briefing also noted that “the agency appears most concerned about the potential lung cancer risk” of taking Orencia.

For its part, in B-MS’ briefing document, the firm “proposes to conduct two large pharmacoepidemiology studies following product approval,” which will “provide more definitive estimates of the incidence rates of serious infections and malignancies in patients treated with abatacept”.

A positive response from the FDA panel will be a major boost for B-MS, as analysts believe Orencia can be a $1 billion drug, and the company will also hoping for a successful hearing for its new diabetes agent Pargluva (muraglitazar) when it comes before an advisory committee three days later [[04/08/05e]].

The pharmaceutical world is also waiting to see whether the FDA, in the post-Vioxx era, has changed its requirements for new drug approval, in terms of the risk-versus-benefit equation.