Over the first 11 weeks, Iclusig NRx has totaled 331 or 30 a week. Over the last 4wks, NRX has averaged 44. Ariad estimates that ~ 2500 U.S. patients will switch their TKI this year. I believe the company only had ~ 150 US patients in its early access program so every indication is that Iclusig is taking market share; however, a weekly NRx of 30 (let alone 44) simply isn't sustainable.
Starting with the current NRx of 331 and assuming a weekly NRx of 30 for the rest of the year would result in Iclusig ending its first 12 months with an NRx of 1,561. Assuming NRx is a rough proxy for subscribers, this would mean that Iclusig would have to capture 60% of the patients who switch therapy. This isn't going to happen, consequently, I suspect over the short-term Iclusig NRx will decline from current levels. At that point, perhaps AF will write another article claiming a weak launch, however, the reality is the launch remains ahead of even the most optimistic analyst estimates.
Claiming Iclusig is "dirty drug" based solely on AEs seen in a 3/4 line setting is a really weak bear thesis (and poor journalism, imo). What matters as much to me as total scrips is the composition of those scrips. For example, how many are CP vs AP vs BP? What line of therapy? How many have the T315I mutation?
Here is what we do know. In a 3rd line CP setting, sprycel achieved a 16 month CCyR of 31% (i'm using sprycel data because the tasigna numbers were worse). In 2L, sprycel achieved a 15mo CCyR of 49% (which is a 58% improvement over the 31% CCyR sprycel got in 3L). In the PACE trial 93% of patients were third-line and 58% were fourth-line. Even though most of these patients had failed 3 prior TKIs, Iclusig still achieved a 46% CCyR at 15.3 months. So will Iclusig also see a significant improvement in a 2L setting? The short answer is we don't know yet however there were 19 second-line CP patients in the PACE trial (13 had previously been treated with imatinib only, 6 had previously received either sprycel or tasigna. Of these 19 patients, 84 percent achieved a MCyR.
Ultimately, this issue will only be resolved once Iclusig demonstrates that it can take 1/2L market share from sprycel/tasigna in CML-CP patients who do not have the T315I mutation. I believe the EPIC trial interim results will demonstrate both the superiority and safety necessary to achieve this result.
