As HAE offerings from Takeda and BioCryst gain steam, a doc survey offers lessons for the long term: analyst

Orladeyo, the first oral option to prevent hereditary angioedema (HAE) attacks, has been on the market for over a year now. A survey shows the BioCryst Pharmaceuticals drug and Takeda’s rival injection Takhzyro have been welcomed by doctors. But both drugs face long-term uncertainties, one analyst says.

A generally positive experience, solid patient retention and a sunny outlook from doctors on script trends all mean BioCryst’s 2022 estimate for Orladeyo sales of $250 million can become a reality, RBC Capital Markets analyst Brian Abrahams, M.D., said in a Friday note.

Orladeyo’s growth will mainly come at the expense of CSL Behring’s Berinert and Haegarda, while Takeda’s Takhzyro—especially its monthly dosing form—will also gain market share, Abrahams noted. His team made the observation based on a survey of 29 U.S. immunologists who treat HAE patients.

Approved by the FDA in late 2020, Orladeyo has captured an average of 16% of HAE patients managed by the surveyed physicians, who expect to increase the use to an average of 29% one year from now, the analyst wrote. After adjustment for changes in the overall number of patients, the results indicated that Orladeyo could see a 71% increase in total patients, Abrahams noted.

During a conference call with investors in February, Biocryst chief commercial officer Charlie Gayer pointed to the company’s own market research in 60 physicians, who indicated they would double Orladeyo use among their existing HAE patients in one year.

Biocryst recorded Orladeyo revenue of $46.2 million in the fourth quarter and $122.6 million for full-year 2021. Based on the current adoption trend and a 3% price increase, Abrahams believes Biocryst could double sales this year and reach its expectation of at least $250 million.

Amid the new competition from Orladeyo, Takeda’s Takhzyro has managed to maintain its foothold. While physicians projected a slight patient share decline from 15.6% to 14.4% for Takhzyro’s more frequent biweekly dosing schedule, they plan to increase the drug’s once-monthly dosing to 14.2% from the current 11.4% in a year, the RBC survey found. Takhzyro was first approved by the FDA in 2018, and it just earned a nod for a more convenient prefilled syringe in February.

But Ionis’ novel antisense drug, donidalorsen, formerly IONIS-PKK-LRx, with the potential to go even less frequent dosing at once every two months, could be a major threat to Takhzyro. About a quarter of responders in RBC’s survey would consider switching nearly all of their Takhzyro patients to a longer-acting injectable with an improved reduction in attacks, Abrahams noted.

In addition, the RBC-surveyed physicians expected they will slightly reduce the use of CSL’s Berinert and Haegarda. About a quarter of existing Orladeyo takers switched from Haegarda, the doctors indicated.

As a result, RBC is lowering its sales outlook for CSL’s HAE franchise. The team is now expecting declines of 5% to 8% a year between fiscal year 2023 and 2026.

The patient drop-out rate has also been lower than what Abrahams had expected for Orladeyo. While a relatively high retention rate is encouraging, “it remains early in the launch to draw definitive conclusions about [long-term] persistence,” Abrahams wrote in his note.

Despite the positive early signs, Abrahams drew one lesson from the roughly one-third of Orladeyo patients who were new to preventative HAE treatment.

“[T]his represents a meaningful portion of new patient starts and a segment where initial potential pent-up demand may be hard to maintain without significant commercial initiatives to increase awareness of mild disease and connect such [prophylactic]-naive patients with HAE specialists,” Abrahams said.

All things considered, Abrahams estimates Orladeyo can reach $570 million in combined sales in the U.S. and Europe down the line. He figured the drug needs better market share dynamic to reach BioCryst’s bullish $1 billion peak sales estimate.