Roche said on Wednesday a late stage trial for its tiragolumab drug to treat small cell lung cancer has failed to reach its targets, dealing a blow to the Swiss company’s effort to develop the next generation of immunotherapy treatments.

The Skyscraper 2 study failed to meet its aim of progression-free survival in patients during a phase III trial, the Basel company said.

The other target of boosting overall survival among patients with the aggressive form of cancer was not met at its interim analysis, the company said.

Levi Garraway, Roche’s Chief Medical Officer and Head of Global Product Development., said:

Today’s outcome is disappointing as we had hoped to continue building on the advances of Tecentriq in extensive stage small-cell lung cancer, which remains difficult to treat.

Roche currently produces Tecentriq, a first generation immunotherapy, and plans to continue trials for tiragolumab in non-small cell lung cancer and other forms of the disease.

If successful, it was expected that tiragolumab could have become a blockbuster drug.

Analysts at Swiss bank ZKB had estimated 3 billion Swiss francs ($3.23 billion) in sales for tiragolumab in 2028. Roche shares were 1.2% lower in early trading, while the STOXX Europe 600 Health Care index slipped 0.5%, as Reuters notes.