Prostate cancer survey indicates strong uptake with regard to new hormone-based agents
Pointing to a MEDACorp survey of 50 U.S. urologists and oncologists (25 in each specialty) with a majority of them practicing in the community setting, healthcare investment banking firm Leerink Swann notes a strong suggestion from the respondents that significant use of Xtandi is occurring in the pre-chemotherapy setting for prostate cancer and is boasting a "near-term sales trajectory that appears to be ahead of expectations."
On the other hand, the survey notes that Provenge is on the decline since the end of 2012.
In aggregate, survey respondents manage twice as many pre-chemo castration-resistant prostate cancer (CRPC) patients as post-chemo patients, according to Leerink Swann. Together with a longer treatment duration, the survey results indicate that the pre-chemo market may be several times as big as the post-chemo market.
The results also indicate a substantial increase of Zytiga and Xtandi of 41 percent and 80 percent, respectively, in the period of December 2012 to March 2013.
"The magnitude of increase in Zytiga use matches the sequential sales growth reported for Zytiga," Leerink Swann notes. "For both drugs, the growth was mainly driven by pre-chemo use and by urologists.
Both Zytiga and Xtandi are projected to grow substantially through the rest of 2013, by 84 percent and 167 percent, respectively, according to the firm, relative to March 2013. By Leerink Swann's reckoning, this means that "the market is by no means saturated."
By physician projections, the number of patients on Xtandi will have nearly caught up with Zytiga by the end of 2013, reportedly.
Somewhat more than half of current Xtandi patients had previously received Zytiga, although this differed significantly between oncologists and urologists, with the latter group having a much lower proportion of Xtandi patients post-Zytiga (28 percent vs. 70 percent) that also declined in the last three months (from 44 percent to 28 percent).
Most physicians in both specialties treat to progression, although nearly a quarter of urologists indicated that in post-Zytiga patients Xtandi would be continued post-progression.
According to the majority of survey respondents, the efficacy and safety and tolerability profiles of Zytiga and Xtandi are similar in the post-chemo setting. Although there are some differences in perception by urologists and oncologists, Leerink Swann believes this may be explained in part by a limited amount of promotion of Xtandi to urologists thus far.
"Assuming [the] PREVAIL [study] demonstrates a statistically significant overall survival (OS) benefit, one-year after presumed Xtandi approval in the pre-chemo setting, Xtandi is projected to overtake Zytiga with a 43 percent market share in the first-line metastatic setting vs. 34 percent for Zytiga," according to the investment bank, which adds that if Xtandi shows only an OS trend, those shares would reverse.
Finally, Leerink Swann notes, survey respondents report declining use of Provenge since December 2012.
"However, Provenge usage is projected to rebound with robust growth by the end of 2013," the firm maintains. "Although many respondents indicated declining use of Provenge after Zytiga pre-chemo approval and Xtandi launch, interestingly this appears to mainly affect the casual users and to have limited impact on existing heavy users."
Proprietary knowledge gained through the MEDACorp network enhances services offered by Leerink Swann, which notes that over the past 15 years, MEDACorp has amassed more than 30,000 healthcare professionals, including key opinion leaders, experienced practitioners and other healthcare professionals throughout the United States, Europe, Asia and other locations around the world.