Option to Purchase Additional Shares
We have granted an option to the underwriters, exercisable for 30 days after the date of this prospectus supplement, to purchase up to
$7,500,000 of additional shares at the public offering price, less the underwriting discount. If the underwriters exercise this option, each will be obligated, subject to conditions contained in the underwriting agreement, to purchase a number of
additional shares proportionate to that underwriters initial amount reflected in the above table.
No Sales of Similar Securities
We have agreed with the underwriters, subject to specified exceptions, not to (i) offer, sell, contract to sell, pledge, grant any option
to purchase, make any short sale or otherwise transfer or dispose of, directly or indirectly, or file with the SEC a registration statement under the Act relating to, any shares of our common stock or any securities that are substantially similar to
our common stock, including but not limited to any options or warrants to purchase shares of our common stock or any securities that are convertible into or exchangeable for, or that represent the right to receive, common stock or any such
substantially similar securities, or publicly disclose the intention to make any offer, sale, pledge, disposition or filing or (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of
ownership of our common stock, or any such other securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of our common stock or such other securities, in cash or otherwise, without the prior
written consent of the representative.
Our directors and executive officers have agreed with the underwriters, subject to specified
exceptions, not to (i) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, make any short sale
or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock or any securities convertible into, or exercisable or exchangeable for, or that represent the right to receive, our common stock (including without
limitation, our common stock which may be deemed to be beneficially owned in accordance with the rules and regulations of the SEC and securities which may be issued upon exercise of a stock option or warrant), whether now owned or hereafter
acquired; (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of our common stock, whether any such transaction described in clause (i) or (ii) above is to be
settled by delivery of our common stock or such other securities, in cash or otherwise, is to be settled by delivery of our common stock or such other securities, in cash or otherwise; (iii) make any demand for or exercise any right with
respect to the registration of any common stock or any security convertible into or exercisable or exchangeable for common stock; or (iv) publicly disclose the intention to do any of the foregoing, without the prior written consent of the
representative. These restrictions will apply through and including the date that is 90 days after the date of this prospectus supplement.
Nasdaq
Capital Market Listing
The shares are listed on the Nasdaq Capital Market under the symbol ATHX.
Price Stabilization and Short Positions
Until the distribution of the shares is completed, SEC rules may limit underwriters and selling group members from bidding for and purchasing
our common stock. However, the representative may engage in transactions that stabilize the price of the common stock, such as bids or purchases to peg, fix or maintain that price.
In connection with the offering, the underwriters may purchase and sell our common stock in the open market. These transactions may include
short sales, purchases on the open market to cover positions created by short sales and stabilizing transactions. Short sales involve the sale by the underwriters of a greater number of
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