The FDA isn't convinced that Amgen ($AMGN) needs another bone-metastasis indication for its new drug Xgeva. The drug is already approved to treat skeletal side effects in cancer patients, but Amgen is asking to market it as a preventive tool for men with advanced prostate cancer. The idea is that earlier use of Xgeva might stave off--or at least delay--development of bone metastases in those men. The other idea, of course, is that marketing the drug for that use could increase sales.
Since the data on preventive Xgeva use came in, though, analysts haven't been very upbeat about those sales prospects. The drug didn't prolong patient's lives, and though it did appear to delay bone metastases, the average increase in "bone metastasis-free survival" was just 4.2 months.
FDA reviewers raised similar questions about the data in documents released in advance of Wednesday's advisory committee meeting. And they cited a 5% increase in cases of jawbone deterioration in Xgeva patients. The agency staffers questioned whether the metastasis-free survival time of just over four months was "meaningful," considering that Xgeva is already approved to prevent bone-related side effects in patients whose cancer has moved into the bone.
"Does early treatment ... add to the benefit provided to patients when denosumab is administered in the metastasis setting?" the agency asked. And the reviewers went on to cite a Lancet editorial that took issue with the proposed new indication. "The reported findings support its use as an alternative to zoledronic acid [Novartis' bone drug Zometa], but do not support its broad use as a preventive agent for bone metastases in prostate cancer," the editorial stated.
As EvaluatePharma notes, an argument could be made for approval based on patients' quality of life--bone tumors are exceedingly painful--but that may not wash with the FDA's expert panel. "With an overall survival benefit, there would have been little doubt Xgeva would gain the prevention indication," the market research firm notes. "As it stands, it will need sympathetic panelists who see the benefit in delaying the onset of the painful bone metastases and, given how Xgeva divides opinion, that outcome seems unlikely."
Advisory committees have surprised observers before, however, so the vote may yet go Amgen's way. And the argument won't be completely over until FDA makes its own decision, expected in late April.