Spectrum Pharmaceutecals Inc (SPPI)

[antihama]

It's interesting to see Xalkori’s growth trajectory since we can surmise a parallel path for pozi. As JT said at the Jefferies CC last week, pozi in exon 20 insertion mutations is ~ 5.5% of the population whereas Xalkori is around 4% for the ALT mutation (i.e. that’s 37.5% more pts). Xalkori for ALT in NSCLC was approved in 2013 w sales growing 5.9% last year to $594M. It was also approved for ROS1 mutations in NSCLC in March 2016 which is about 1% of NSCLC pts (I'm assuming that that 4% JT mentioned doesn't include ROS1 patients). It also just rec’d BTD for MET exon 14 NSCLC + ALK-positive RR systemic ALCL but since it’s not approved for these indications and since the drug for ROS1 mutations in NSCLC is probably just getting up to speed I would guess ~550M of sales comes from treating ALT patients. Going forward sales will be impacted by other ALT TKIs such as Alecensa (alectinib) where the PFS for the Alecensa group was 34.8 months compared to 10.9 months for the Xalkori group but for now we can assume Xalkori’s (worldwide) sales of around $550M was due to treating ALT patients. If you assume that pozi in exon 20 insertion mutations will treat 37.5% more patients than Xalkori (or $550M * 1.375) that comes out to $756M if you double that to account for exon 20 insertion mutations in other tumor types other than NSCLC that becomes $1.512B in sales.

Previously, I calculated $6B in potential sales in post 2181

We know from the SPPI presentation that the EGFR and HER2 exon 20 insertion mutations affect ~19,700 patients worldwide (US, EU + Japan) in NSCLC. From the video, for the first time, we get a sense of the prevalence of these mutations in other cancer indications. He mentioned that you can find EGFR and HER2 exon 20 insertion mutations in some 20 other cancers and that when you add the sum of them together it’s more than you find in NSCLC. So that’s ~40,000 pts. If you multiple that by what is charged for Tagrisso or $153,000/ yr that comes to $6.12B. That's huge! and just amazing to think about!

Using either calculation method makes sense to me so, I dunno, for now let’s say that pozi potential sales for exon 20 is somewhere in between those 2 figures. It could be that Xalkori’s worldwide sales hasn't taken off yet while I'm assuming 100% penetration worldwide for pozi. Let’s just say, for now, pozi’s potential is an average of those 2 figures or 3.8B…not bad!

Edit - Actually in the follow-up post to 2181 i.e. post 2182, I state that the potential 6B in sales will be affected by

Another factor that will affect the sales projection is how long will mPFS be. Right now it’s at 6.6 months, say it settles at 8 months, that’s only 2/3 of a year so you will need to decrease that sales projection by a third, if it’s over a year you’ll need to increase accordingly.

So if you'd multiple $6B by two-thirds that becomes $4B and we're more in the ball park since Xalkori's PFS is around 10m in the Alecensa (alectinib) placebo (Xalkori) controlled trial but was 7m in the pivitol Xalkori trial for approval.