(Adds analyst, company comment, share price)
By Deena Beasley and Tamara Mathias
June 14 (Reuters) - Bluebird bio Inc on Friday set a price for its gene therapy, Zynteglo, at 1.58 million euros ($1.78 million) over five years, after winning conditional approval in Europe this month to treat a rare genetic blood disorder. The company proposed an installment plan, with 315,000 euros paid up front and four additional annual payments due only if the treatment continues to be effective.
Zynteglo was approved in Europe for patients age 12 and older with beta thalassemia who require regular blood transfusions and have no matching donor for a stem cell transplant. The inherited disorder limits the blood's ability to carry oxygen throughout the body.
Bluebird, which is also testing Zynteglo for sickle cell disease, said it expects the therapy to be approved for beta thalassemia in the United States in 2020. Wall Street analysts forecast Zynteglo beta thalassemia sales of about $828 million by 2024, according to data from Refinitiv.
The company said it does not expect to begin treating patients in Europe until next year as it works out reimbursement terms with individual countries and authorizes treatment centers.
William Blair analyst Raju Prasad said there had been expectations on Wall Street of Zynteglo sales this year, which could be hurting the share price. Bluebird shares were down more than 5% at $117.17.
Pharmaceutical companies have been investing heavily in potentially life-changing gene therapies over the past few years, but they come with hefty price tags. As a result, some are experimenting with so-called value-based pricing, which can involve refunds if a therapy fails to deliver on its promise.
Bluebird said it believes the "intrinsic value" of its one-time infusion is about $2.1 million per patient, and the price reflects the ability to avoid costly blood transfusions, improve quality of life and potentially cure patients.
Bluebird said it aims to price Zynteglo in developed nations, including the United States, within a "reasonably close" range. The company said patient access talks are underway with health authorities in Germany, Italy, France, and Britain.
"The one-time potentially curative nature of what we have on our hands here sort of warrants this type of a (pricing) model in a more aggressive way," bluebird Chief Executive Officer Nick Leschly told Reuters in a phone interview.
Gene therapies are single treatments designed to deliver healthy genetic material into a person's cells to correct genetic defects that cause serious diseases.
Whether these high priced new therapies can succeed in Europe, where countries have stringent price controls, remains to be seen.
The first two gene therapies were approved in Europe - UniQure NV's Glybera in 2012 for a very rare blood disorder and GlaxoSmithKline's Strimvelis in 2016 for "bubble boy" disease - but sales were small. Glybera is no longer available and GSK sold Strimvelis to Orchard Therapeutics.
"We continue to believe that Zynteglo uptake will be challenging," Piper Jaffray analyst Tyler Van Buren said in a research note, citing the small number of patients treated in clinical trials and the fact that most patients are adequately maintained on transfusions.
But drugmakers are forging ahead with promising new gene therapies that will continue to test pricing limits.
In May, Swiss drugmaker Novartis won U.S. approval for its gene therapy for spinal muscular atrophy and priced it at $2.125 million, making it the world's most expensive drug. Novartis defended the price by saying that a one-time treatment was more valuable than expensive long-term treatments.
Spark Therapeutics Inc, which is being acquired by Roche Holding AG, won U.S. approval for its gene therapy to treat a rare form of blindness in 2017, pricing it at $850,000. (Reporting by Deena Beasley, Tamara Mathias and Aakash Jagadeesh Babu; editing by Bill Berkrot)