ADMA Biologics Inc. said it will retire about 8.6 million common shares held by Biotest Pharmaceuticals Corp., which is divesting its U.S. assets.

The nonvoting shares represent about 19% of ADMA Biologics and will be transferred back to the company.

In June 2017, ADMA had issued 12.9 million of its shares as total consideration for buying Biotest's therapy business unit. The company, which had also transferred two of its plasma collection centers as part of the 2017 agreement, said it has the right to purchase the remaining shares for a certain period of time.

As it stands, Biotest can no longer name a director and observer to the ADMA Biologics board. Meanwhile, ADMA Biologics can no longer repurchase the two Georgia-based plasma collection centers, which will be transferred to Biotest on Jan. 1, 2019.

ADMA Biologics President and CEO Adam Grossman said the transaction simplifies the company's capital structure, reducing its total stock to 36.7 million shares from 45.3 million shares.