U.K. watchdogs back Strimvelis' $714K price, just as GlaxoSmithKline considers selling it off

GSK's gene therapy Strimvelis won backing from U.K. cost watchdogs in a final draft guidance.

While they don't always decide in favor of pharma's hot new launches or pricey cancer drugs, the influential cost watchdogs at England's NICE have given their final nod to GlaxoSmithKline's "bubble boy syndrome" therapy at a price of £594,000 ($714,000).

It's good news for Glaxo, which won European approval for Strimvelis back in May 2016. But the decision also helps illustrate the financial peculiarities of gene therapy for rare diseases, a field that GSK may decide to leave to others.

Strimvelis is obviously pricey, but as a gene therapy, it's a one-time treatment. As a remedy for an ultrarare immune system disorder—also known as ADA-SCID—the number of patients eligible to use it is very small. For cost-effectiveness gatekeepers, that makes the drug affordable: A NICE appraisal committee found that the treatment's 5-year budget impact would be £2.35 million ($3.18 million).

RELATED: GlaxoSmithKline's talk of leaving rare diseases—amid slow Strimvelis sales—highlights challenges in the field 

Of course, that budget impact represents a less-than-desirable outcome for a for-profit drugmaker. GSK told FiercePharma only four patients have been treated with Strimvelis so far—total. And last summer, the company said it's exploring a sale for its rare diseases unit, which includes Strimvelis and two other programs in development. 

At the time, a spokeswoman said the potential sale could benefit patients. While GSK has “been heavily invested in this area, we believe there is someone else who can best ensure the commercial availability of these medicines for patients,” she said.

The company doesn't plan to abandon cell and gene therapy R&D, she added, but plans to focus on cancer and more common indications rather than ultrarare diseases.

GSK isn't alone in facing slow sales for a gene therapy. UniQure let the marketing license for the world's first—Glybera—expire because its sales weren't enough to offset marketing expenses.

RELATED: With its launch fizzling out, UniQure gives up on $1M+ gene therapy Glybera 

NICE's recommendation will pave the way for more patients to be treated with Strimvelis, however. Confirming its draft recommendation last fall, the agency has backed the drug to treat ADA-SCID in patients not suitable for stem cell transplant. The new guidance is subject to appeals, and NICE expects it to be final next month if there are no appeals.

On Wednesday, a spokesperson said the company is "delighted that this positive guidance from NICE now enables families in the UK who have a child with ADA-SCID and no suitable matched stem cell donor to benefit from Strimvelis.”

The news comes as Spark Therapeutics announced an $850,000 price tag before discounts in the U.S. on its gene therapy Luxturna, approved to treat a rare form of vision loss that can lead to blindness. The company introduced outcomes-based deals with Harvard Pilgrim and Express Scripts affiliates to help share the cost burden.

Both Luxturna and Strimvelis are one-time treatments intended to cure a patient's disease, compared to other superpricey drugs that are given on a recurring basis.