(Bloomberg) -- Daiichi Sankyo Co. shares jumped by the most in a year after a drug it developed with AstraZeneca Plc showed favorable results in a trial for a common type of breast cancer.

Japan’s biggest drugmaker by market value climbed as much as 8%, leading its peers on the Topix’s gauge of pharmaceutical companies, which was the best-performing sub-index on Monday.

Astellas Pharma Inc. also advanced, following positive results from a bladder cancer study. The moves reflect some reassessment of the industry, which has lagged the broader market’s 26% rise this year with an increase of just 8%. 

“A series of positive news coming from drugmakers is making investors take another look at the sector’s positioning as a whole,” said Hajime Sakai, chief fund manager at Mito Securities Co. 

Read more: AstraZeneca, Daiichi Breast Cancer Drug Shows Benefits

The drug from Daiichi Sankyo — known as datopotamab deruxtecan, or Dato-DXd — showed a statistically significant and clinically meaningful progression-free survival benefit in patients with HR-positive, HER2-low or negative breast cancer, AstraZeneca said on Friday.

The announcement came earlier than scheduled and the wording of the statement was positive, Citigroup Global Markets analyst Hidemaru Yamaguchi wrote in a note dated Friday. The drug may have the potential to generate ¥1 trillion ($6.7 billion) in sales, he said.

Jefferies Japan Ltd. raised its sales estimates for Daiichi Sankyo while cutting its recommendation on the stock to hold from buy, citing the need to assess the level of spending by the company, according to a note from analyst Stephen Barker.

--With assistance from Toshiro Hasegawa.

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