(Reuters) - The Alzheimer's Association may not offer an early look at highly sought clinical trial data on an experimental drug from Eli Lilly and Co after news of the impending release led to a jump in the company's shares.

The influential patient group had been expected to post abstracts containing detailed trial findings on its website in the coming days, ahead of a conference planned for July in Washington, D.C.

Data in the abstracts would have been subject to an embargo, barring their public release until the conference. But participants who were registered to attend the meeting would have had access to their contents, raising questions about whether that would give them information that could influence stock market trading.

Shares of Lilly have jumped 7 percent this week, largely on Wall Street expectations that favorable long-term effectiveness data could emerge from the study of solanezumab, an injectable drug with potential to become the first approved treatment to delay progression of Alzheimer's.

A spokesman for the Alzheimer's Association told Reuters on Thursday that the abstracts, summaries of clinical trial data to be presented at the meeting, could be posted within a few days on a special website for those registered for the event. He said the data would be strictly "embargoed" from publication or distribution until the meeting next month.

Asked if industry analysts, investors or others who might be tempted to trade on the information would be held to the same secrecy ground rules, he said "everyone" would be.

But on Friday, the Alzheimer's Association seemed to be reconsidering its plans, saying, "AAIC abstracts have not been published and there is no plan to publish them at this time. If and when they are published, we will alert people who are registered for AAIC to their availability."

Nicole Hebert, a spokeswoman for Lilly, said the company received numerous queries on Thursday from people about whether embargoed data from the trial were available. She said the company did not have discussions with the Alzheimer's Association about its embargo policy, and had no position on it.

Some Wall Street analysts had alerted their clients in research notes that the Alzheimer's Association would publish the abstracts as soon as today.

Eric Siemers, head of Lilly's Alzheimer's programs, on Thursday told Reuters the main abstract for solanezumab would contain virtually all important data from the study. He said that would be a departure from usual practice, in which abstracts provide only limited information.

Registration for the July 18-23 meeting is open to anyone, regardless of profession, who has paid the registration fee of up to $1,040.

(Reporting by Ransdell Pierson, editing by Michele Gershberg and Richard Chang)