An executive at SillaJen suddenly sold 160,000 shares for “personal reasons,” but other shareholders of the biotech firm worried the selling might signal something negative about the company’s anticancer pipeline Pexa-Vec.

SillaJen said in a public filing on Monday that Shin Hyun-pil, chief science officer of SillaJen, sold all of his 167,777 common stocks on four trading acts between Monday and Friday last week. The stock price of SillaJen during the cited period was between 49,061 won ($41.6) and 54,645 won. Shin gained about 8.8 billion won ($7.4 million) through the selling.

However, the timing of the selling drew attention because SillaJen is soon to unveil the result of the futility analysis on Pexa-Vec, an oncolytic virus against liver cancer. The result will be a significant evaluation tool to gauge whether Pexa-Vec can be successfully commercialized.

The company is to reveal the analysis result in the third quarter. Shin’s selling of shares made other shareholders of SillaJen on edge.

However, the company said Shin sold the shares for personal reasons.

“He sold the stocks to pay taxes and personal debt, following the receiving of stock options last year,” an official at SillaJen said. “His position is not related to R&D division, and he is not leaving the company, either.”

Shin received 5.2 billion won worth stock options in the first half of last year, which generated massive taxes and debt issues, according to the company.

However, SillaJen shareholders questioned why Shin had to sell the stocks if the futility analysis result is to turn positive. Despite the company’s explanation, the repercussions of Shin’s selling are likely to persist for some time, observers said.