Alexion sits on Strensiq nest egg

US FDA approval for Strensiq bolsters Alexion Pharmaceuticals’ position as an ultra-orphan drug leader – but the more interesting development is the paediatric disease priority review voucher that the company received at the same time.

Judging by the increasing prices for which these vouchers have been selling, Alexion’s should be worth over $350m. But the company certainly does not need the cash right now, so it might hang on to the voucher until it commands an even higher premium. 

Even though Alexion has said it plans to use the voucher itself "opportunistically", other companies might be interested if it does decide to cash in. A potential buyer could be a CAR-T or immuno-oncology combination therapy developer, where speeding up approval by four months should be worth a lot in an increasingly competitive field.

Who will buy?

In CAR-T there are several companies lagging Novartis that could make good use of a voucher, including Celgene-partnered Juno, Kite Pharma and Cellectis. Whether most of these have the spare cash to buy it is another question – maybe Juno, with Celgene's backing, is the most likely candidate.

As for immuno-oncology combinations, AstraZeneca has made no secret of ambitions for its anti-CTLA4/PD-L1 inhibitor combo, made up of tremelimumab and durvalumab (Asco – Check mate for combination promise and shortcomings, May 31, 2015). But Astra already has a voucher that it acquired from Wellstat for an undisclosed fee. 

The other big player in PD-1 inhibition is Merck & Co with Keytruda, while Roche is expected to file its anti-PD-L1 MAb atezolizumab next year. These companies are looking to external partners for combinations, but Roche might still be interested in a voucher to speed approval of atezolizumab in lung cancer, where it risks losing ground to Opdivo and Keytruda, both recently approved in non-small cell disease.

If Alexion does indeed use the voucher for one of its own products, the most likely candidate seems to be SBC-103, currently in phase II for metabolic Sanfilippo syndrome, but it does have several other drugs in phase II and I development.

Growing price tag

The price tag for priority review vouchers has increased steadily since Sanofi and Regeneron handed over $67.5m for Biomarin’s in July 2014.

Most recently, AbbVie shelled out $350m for a voucher, and extrapolating these figures would put Alexion’s as being worth around $500m. The US voucher scheme is formally to end in March, though it seems likely to be extended.

Alexion, which sells the world’s most expensive drug in Soliris and is sitting on a cash pile of nearly $2bn, will not be desperate to sell the voucher – which could help it negotiate an even higher price eventually. On the other hand, if the scheme is extended and many more vouchers are issued their price would be expected to come down.

For now, Alexion can focus on Strensiq, which now has the go-ahead in paediatric-onset hypophosphatasia. EvaluatePharma consensus forecasts sales of $724m by 2020.

And more good news could come soon; Alexion’s Kanuma for lysosomal acid lipase deficiency has a PDUFA date of December 8. However, the $706m 2020 consensus revenue forecast does make the $8.4bn that Alexion paid for originator Synageva Biopharma look rich.

Enobia Pharma, which developed Strensiq, now seems like a relative bargain at $470m. As well as the money the drug itself will bring in, the priority review voucher also looks set to be a nice little earner – if a buyer desperate for a few months’ advantage emerges.

This story has been changed to reflect Alexion comments during its conference call.

To contact the writer of this story email Madeleine Armstrong in London at [email protected] or follow  @medtech_ma on Twitter