By Maggie Fick

LONDON (Reuters) - AstraZeneca investors will look past another strong set of quarterly results on Thursday to focus on the main issue overhanging shares: an investigation of a top executive by authorities in China, one of its key markets.

The group said on Oct. 31 that its China head Leon Wang, who also led its international business as an executive vice president, had been detained by the Chinese authorities. It said it did not know what the investigation was about.

    Unless the company discloses fresh information about the probe and arrest at the release of fourth-quarter results, investors are likely to resume selling the stock even though the company's drug pipeline is viewed as strong, four healthcare investors and four analysts told Reuters.

"This blindsided the company," said AstraZeneca shareholder Lucy Coutts at investment firm JM Finn, noting the "void" of information about the probe.

"We don't have visibility on how or when this will be resolved," said Redburn Atlantic analyst Simon Baker. "This is the focus at the moment. It shouldn't be, but it is."

    Wang's arrest was followed by other revelations, including that more than 100 former sales staff in China had been sentenced to jail time in a large and ongoing medical insurance fraud case.

In November the company reported a third investigation in China involving two current and two former senior executives, relating to the import of AstraZeneca cancer drugs from Hong Kong. It said the probe targeted only the individuals, not the company.

AstraZeneca declined to comment for this article ahead of results.

China has long been a key market for the drugmaker, the crown jewel of its international business that accounted for 13% of total sales in 2023.

The Anglo-Swedish group announced plans in 2023 to build a $450 million factory in China. It signed several licensing deals with Chinese companies that year, and bought a China-headquartered biotech company.

Chief Financial Officer Aradhana Sarin told investors at the JPMorgan Healthcare Conference last month the company anticipates some revenue impact on its China business in the fourth quarter and into 2025. Investors are hoping for more information on Thursday.

SMALL RECOVERY

AstraZeneca shares have recovered after the initial news of Wang's detention wiped around $18 billion off their value. They are up about 2% since early November.

In December, AstraZeneca replaced Wang with senior executive Iskra Reic as executive vice president for international, based in Shanghai.

Several investors said it may be tough for an executive who does not speak Mandarin and has never lived in China to navigate such a complicated market at a very sensitive time.

Barclays analysts said in a recent note they believe AstraZeneca may pay a penalty to resolve the Wang investigation. In 2014, British drugmaker GSK was fined nearly 300 million pounds ($372 million) by a Chinese court for bribery.

"Whilst there could be some commercial impact coming from lack of promotion whilst the investigation is ongoing, we view this as digestible given the momentum elsewhere in the business," Barclays said.

($1 = 0.8054 pounds)

(Reporting by Maggie Fick; Editing by Josephine Mason and Jan Harvey)