A pharmaceutical firm's tardiness in taking safety precautions with a drug linked to more than 120 deaths may have been due to concerns that such moves could have hampered the drug's approval overseas, it was learned Sunday.

The claim was brought to light when incriminating e-mail correspondence was discovered in October.

At issue is the lung-cancer drug, Iressa, manufactured by AstraZeneca Group PLC of Britain. It was approved by the Health, Labor and Welfare Ministry in July 2002, but 124 people had died from side effects as of Dec. 13.

According to sources close to the case, a copy of the e-mail correspondence in question was obtained by the Osaka Prefectural Government during a search of AstraZeneca's Japan offices in October. The search was conducted after the firm was found to have delayed reporting the side-effects cases to the health ministry.

In the e-mail, dated Sept. 12, the company official in charge of the drug reported on a meeting held the previous day and said that a "detailed study of the cases of side effects shows that it is difficult to reject links to Iressa, and measures need to be taken."

The mail also said that the health ministry might issue instructions to the firm, indicating that the firm was already aware of the problems posed by the drug at that time.

The ministry ordered the firm on Oct. 15 to issue a warning to medical facilities about the dangers of the drug.

The e-mail went on to say that "changing the wording of documents attached to the drug would affect screening in other countries." and that "we may have to negotiate with the health ministry in line with the wishes of (our parent firm in Britain)."