Entasis Therapeutics Holdings Inc. agreed to sell common shares for up to $20 million to Chicago-based private fund Aspire Capital Fund LLC over a period of 30 months.

Under the agreement, Waltham, Mass.-based biotechnology company Entasis can sell up to 2,626,165 common shares to Aspire Capital, including 104,167 shares issued to the asset management firm as consideration for entering into the agreement.

Entasis will require shareholders' approval to sell more than 19.99% of the company's outstanding shares to Aspire Capital. However, if all shares under the purchase agreement are sold for an average price equal to or greater than $5.75, the approval restriction will not apply.

Entasis and Aspire Capital did not hire any agent, broker or financial adviser for the deal.