AstraZeneca Plc has agreed to buy a portfolio of rare disease gene therapies from Pfizer Inc. as the UK drug company reported sales and profit that beat analysts’ estimates in the second quarter.

The agreement with Pfizer is worth up to $1 billion plus tiered royalties on sales after that, the company said Friday. The transaction is due to complete in the third quarter.

The deal with Pfizer will accelerate the company’s ambitions to grow in cell and gene therapies, AstraZeneca Chief Executive Officer Pascal Soriot said in a Bloomberg TV interview.

In a further development, the company also announced that Sharon Barr, executive vice-president of biopharmaceuticals research and development will succeed Mene Pangalos who is retiring after nearly 14 years at Astra.

Astra also reported half-year results with sales and profit beating expectations. Still, questions remain for Astra on the trial results from its potentially game-changing lung cancer drug, datopotamab deruxtecan, that could overtake standard chemotherapy as a treatment option.

Shares in Astra and partner on the drug Daiichi Sankyo Co. fell sharply earlier this month following initial indications that raised questions about the drug’s effectiveness and safety.

Soriot said high level results released from its key lung cancer trial earlier this month that sent the stock tumbling are positive and when the full results are published people will be encouraged.

“I have no doubt that when they see the detailed results they will be encouraged by what they see,” Soriot said in an interview with Bloomberg TV. This product “will have a very important role to play.”

Soriot said the company has been talking to the FDA about filing its results and “the FDA themselves see positive outlook for this product.”

(Updates with additional information)