Summit Therapeutics plc agreed to sell 15,625,000 American depositary shares, or ADSs, at $1.60 apiece in a private placement.

The ADSs, which are worth $25 million, represent 78,125,000 ordinary shares of Summit Therapeutics.

Robert Duggan, CEO of private investment firm Duggan Investments, is subscribing to the ADSs. The sale would increase his ownership in Summit Therapeutics to about 48.81%, from about 0.2%. Duggan is the former chairman and CEO of Pharmacyclics Inc. which was sold to AbbVie Inc. in 2015.

Duggan is currently the chairman of Pulse Biosciences Inc.

The sale is subject to certain shareholder approvals and customary closing conditions.

Summit Therapeutics said proceeds will be used for its clinical development programs and general corporate purposes. The biopharmaceutical company, which develops antibiotics for certain infections, also said the funds will help extend its cash runway through Jan. 31, 2020.

U.K.-based Summit Therapeutics said it will apply to list the new ordinary shares sold under placement on the London Stock Exchange's AIM market, and expects it to start Jan. 8, 2019.