Victoza Gets Past FDA, But....

There are a few caveats. First, a black box warning for the once-daily GLP-1 analog which includes a potential increased risk of thyroid cancer (despite Novo Nordisk's repeated claims that this applies only to rodents, not monkeys or humans). Second, no first-line usage allowed. Third, significant post-approval requirements, including a CV safety study, a 5-year epidemiological study to evaluate thyroid cancer risks, a 15-year cancer registry to monitor thyroid cancer cases, and a REMS.

As such, "it's a worst case label for the product," concluded Sam Fazeli, an analyst at Piper Jaffray in London. "Bittersweet" was how Jefferies' Jeffrey Holford put it, while Citigroup simply cut to the chase with "Commercial success far from certain."

Things could have been still bleaker, though. At least the US approval has finally happened (the drug was filed in May 2008). It might have been pushed out significantly further, given the regulators' apparent problem with the thyroid cancer risk. And on the up-side, there's no need for calcitonin monitoring during Victoza therapy (calcitonin is the marker used in humans for thyroid cancer) and there are no broad contra-indications for the drug. Only patients with a family history of medullary thyroid cancer, or multiple endocrine neoplasia syndrome, aren't allowed Victoza--and both those indications are very rare.

As such, Novo's management was upbeat during the analyst call announcing the news. The REMS is very remiscent of that recently imposed on Lilly/Amylin's twice-daily GLP-1 analog Byetta, said EVP & CSO Mads Thomsen, and certainly manageable. He added that many diabetes drugs (metformin, the sulphonylureas) have black box warnings, and most new products aren't awarded first-line treatment at their first pass at FDA. Thus, "we're perfectly happy with our monotherapy label," he said. (The product was denied approval as a monotherapy in Europe).

There a big 'but', though--and it's Byetta. That product has not only a five-year head start, but also hasn't got a black box, hasn't got a thyroid cancer risk warning, can be used as an initial therapy, and thus remains "first choice" treatment in this class, according to Fazeli, despite its more frequent administration.

This explains the generally (although not exclusively) down-beat analyst reaction to the news; "we see more room for disappointment than surprise on Victoza," writes Citigroup's Mark Dainty. Never mind the fact that Victoza outperformed Byetta in blood sugar lowering in a recent Phase III head-to-head trial.

Novo's management still thinks it can surprise, however. (They're a confident lot.) They re-iterated their forecasts that Victoza will reach sales of over $1 billion by 2015 (Byetta's currently at about $700 million and it has been on the US market since 2005).

Much will depend on whether follow-on GLP-1 analogs including long-acting Byetta (EQW) and Roche/Ipsen's taspoglutide are stamped with the same thyroid cancer warnings as Victoza. (Amylin's epidemiological study of Byetta is due March 31). Novo's Thomsen is adamant that the thyroid cancer signal seen among rodents is a class-effect among the long-acting GLP-1 analogs, and points to a forthcoming peer-reviewed scientific paper outlining what he claims is a similar pre-clinical effect on thyroid c-cells for Victoza, long-acting Byetta and taspoglutide. "We'll have to live with the notion that long-acting GLP-1 analogs cause c-cell proliferation in rodents," he told The In Vivo Blog. "But there's no reason to believe that these findings have any relevance to higher species," he added.

Whether or not the other long-acting GLP-1s get the same treatment, FDA is unlikely to remove Victoza's black box for several years at least, likely until the 5-year follow-up cancer study data is available.

Meanwhile, though, with its already-expanded US sales force and pricing in line with Byetta at about $8/day for the 1.2mg dose, Novo will be pushing Victoza with all its might and leveraging its wider diabetes franchise where possible. And let's not forget the fundamentals: Victoza is once-daily, can be taken anytime, prompts some weight loss, isn't associated with hypoglycemia or significant nausea, and is relatively easy to titrate.

Those elements may yet trump the worries about cancer in rats.