At the biotech's business update meeting today, Amgen president and COO, Robert Bradway, said he hopes to build the denosumab franchise to $3-$4 billion of worldwide sales by 2015. Especially with Prolia's first-quarter sales sluggish, that forecast will depend largely on the other half of the denosumab duo—Xgeva—seeing better adoption by prostate doctors and urologists and differentiation from Novartis' Zometa.
Xgeva US sales were $42 million in the first quarter, Amgen said, beating analyst consenus of $23 million. That reflects uptake by hospitals and oncology clinics and, to a lesser extent, urologists—prospects the company's specialty sales reps have been targeting since a November launch.
The drug, used monthly to help prevent bone-related complications in some patients with advanced cancer, is a higher dose of Amgen's denosumab injection, which was approved the previous June for osteoporosis and is marketed under the name Prolia. Prolia first-quarter sales disappointed at $27 million, below the consensus estimate of $32 million.
As part of an investor presentation, Bradway said Xgeva usage is heaviest among patients with breast cancer (45%), as well as other solid tumors and prostate cancer, in hospital settings or oncology clinics. Urology accounts for only about 5% of sales of Xgeva first-quarter sales.
“We have strong share amongst those urologists who are treating bone mets [metastasis], but there's clearly an opportunity for us to expand into a number of urology clinics that aren't presently treating those patients,” he said, according to a transcript from SeekingAlpha.
The numbers suggest oncologists treating bone metastasis for prostate cancer sufferers have moved quickly to adopt Xgeva, but not urologists. That has some analysts concerned, because both kinds of specialists will need to be on board if Amgen wants to build on sales. The company plans to apply to broaden Xgeva's label based on recent data that showed its ability to delay the spread of prostate cancer to the bone. The additional indication could help differentiate the drug from Zometa, which costs about half as much and is approved to reduce and delay bone complications in patients with various cancers, including solid tumors and multiple myeloma.
Based on a survey of oncologists (n=18) and urologists (n=21) by Jefferies Research, 54% don't think Xgeva's attributes warrant a roughly 65% premium pricing to Zometa, although about 90% think Xgeva's 18% risk reduction in time to first skeletal-related event (SRE) vs. Zometa is clinically meaningful.
About 69% of the respondents think Xgeva's ability to prevent bone metastasis in hormone refractory prostate cancer (HRPC) is “a much stronger rationale to switch patients from Zometa than SRE prevention data,” noted Jefferies analyst Eun Yang. "If approved, the surveyed expect to use XGEVA in ~47% of their HRPC patients with no evidence of bone mets.”
And 97% of those surveyed expect Xgeva attributes to expand the number of patients receiving therapy for bone metastasis by about 24%, Yang noted. “Despite its hefty premium pricing, the survey shows XGEVA attributes likely driving market share. From survey results, we could see ~$1.6B in potential XGEVA sales (vs. our/consensus 2015 sales estimates of ~$1.4B/~$1.9B).”