This one wasn't on the radar. Until now.
If/when Ariad gets approval to market Ponatinib for GIST, it means that it's the drug of choice - first line for this indication. Note that we already have FDA DESIGNATION of orphan status of Ponatinib for the GIST indication. What we don't have yet is approval to market for this indication. And if that happens, we have huge and unanticipated catalyst. Here's why.
1. Orphan status gets you a monopoly protection for the indications for 7 years, per FDA guidelines.
2. Per above, we shoot to first line as its clearly the drug of choice (only one drug gets orphan status per indication).
3. Additional revenues of up to $1.5 billion. The model to calculate the potential revenue range follows below. Suggestions to improve the model and assumptions are more than welcome, so please do weigh in.
Here are the assumptions.
- Annual INCIDENCE of GIST (new cases) estimated at 3,300 to 6,000 in the US. This estimate is from the National Cancer Institute. See: National Cancer Institute GIST Incidence Estimate
- Use endpoints of NCI incidence for annual new cases, multiply by percent of cases treated with Iclusig: LOW estimate = 50%, HIGH estimate = 100%
- Estimate number of years a patient is on treatment: LOW = 1.5 years, HIGH = 2 years. Note: This is probably the weakest link in the model, as I don't have data on how long patients would need to be on treatment.
Low Estimate High estimate Global Annual Incidence of GIST 3,300 6,000 No. Cases Treated with Iclusig 50% 100% Culmulative Years' Incidence being treated per year 1.5 2 Total Case treated with Iclusig per year 2,475 12,000
Annual cost of treatment
$125,000
Annual GIST related Iclusig Revenue$309m $ 1.5b
I welcome your suggestions on how to improve these estimates.
You should use WW population, so starting with 7 per million for US+EU+JP you get 45,000. Only 1/3 of these are malignant, advanced stage, and therefore suited to targeted therapy, so then 15,000. Of these only 85% have KIT/PDGFR mutations, so then 12,750. After 1st line generic imatinib the pool would be reduced by another 20% for second line, leaving 10,000 for Pona to wrestle with sunitinib for market share. Since others are in the pipeline, and not all KIT/PDGFR mutations are handled by Pona I would assume 30-40% market share. By 2016 $125,000 for treatment will be fair value so peak WW sales could reach $440M by 2020.
ReplyDeleteExtremely helpful, thank you! Quick questions: 1) Could you share a link/source for the global incidence estimate? 2) Any guess on probable duration of treatment? Finally, I completely agree re market share, and my range was 10-50% (admittedly, too large a range). Again, many thanks for these helpful comments.
ReplyDeleteWell 7 per million is pooled from several sources, but the link below summarizes various numbers ranging from 6.8 to 14 per million. The 6.8 per million US is most recent. For duration I think second line is more like 1-2 years, not 2-3, but depends which mutation is driving imatinib failure, so one could argue for 1-3 years.
ReplyDeletehttp://annonc.oxfordjournals.org/content/17/suppl_10/x280.full.pdf?
origin=publication_detail
According to this new article incidence is higher....15 per million...which yields 15,000 WW in developed countries (NA/EU/JP/AU/NZ). I would assume roughly half of those are advanced stage and therefore suited for frontline TKI therapy, less for later lines.
ReplyDeletehttp://jco.ascopubs.org/content/early/2014/05/20/JCO.2013.51.6633.full.pdf+html