The spinal muscular atrophy (SMA) treatment, approved by the U.S. Food and Drug Administration in May, has reaped $175 million in revenue this year, including $160 million in the third quarter.

On a call following third-quarter results, Chief Executive Vas Narasimhan said roughly 100 patients have been treated under the paid programme.

The figures would suggest it is receiving around $1.75 million per patient on average, a 17% discount to the U.S. list price. Novartis has said previously it was offering discounts to U.S. insurers on the condition they add Zolgensma to their policies to ensure quick authorisation.

"With respect to Zolgensma, you have to divide the total sales by the net pricing that we've achieved and also look at our U.S.-EU mix," Narasimhan told analysts on the call. "We're in the range of 100 patients treated currently under the paid programme."

Narasimhan also told reporters on Tuesday that insurers are seeking to tie payments to Zolgensma's long-term efficacy, but said he has seen no "material uptake" of five-year instalment plans that Novartis has suggested to help soften the financial burden.

Novartis declined to confirm the average per-patient cost figure based on revenue and patients treated.

(Reporting by John Miller; Editing by Michael Shields)