The information in this prospectus is not complete and may be changed. The selling
stockholder named in this prospectus may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and the selling stockholder
named in this prospectus are not soliciting offers to buy these securities in any jurisdiction where the offer or sale is not permitted.
Subject to completion, dated October 5, 2020
PROSPECTUS
10,551,899 Shares of Common Stock
This prospectus relates to the resale, from time to time, of up to 10,551,899 shares of our common stock, par value $0.001 per share, by the
selling stockholder, Lincoln Park Capital Fund, LLC, which we refer to as Lincoln Park or the selling stockholder. The shares of common stock to which this prospectus relates includes shares that have been or may be issued to Lincoln Park pursuant
to a purchase agreement between us and Lincoln Park dated September 21, 2020, which we refer to as the Purchase Agreement.
We are not selling any securities under this prospectus and we will not receive any proceeds from the sale of the shares by Lincoln Park.
However, we have received gross proceeds of $500,000 from the sale of certain of the shares under the Purchase Agreement and may receive additional proceeds of up to $14,500,000 from the sale of additional shares to Lincoln Park under the Purchase
Agreement, from time to time in our discretion after the date of the registration statement of which this prospectus is a part is declared effective and after satisfaction of other conditions in the Purchase Agreement.
Lincoln Park is an underwriter within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended, or the
Securities Act.
Lincoln Park may sell the shares of common stock described in this prospectus in a number of different ways and at
varying prices. See Plan of Distribution on page 24 for more information about how Lincoln Park may sell the shares of common stock being registered pursuant to this prospectus.
We have agreed to bear all of the expenses incurred in connection with the registration of the shares to which this prospectus relates.
Lincoln Park will pay or assume discounts, commissions, and fees of underwriters, selling brokers or dealer managers, if any, incurred in connection with the sale of shares of our common stock.
Our common stock is listed on the Nasdaq Capital Market, or Nasdaq, under the symbol ALRN. On October 2, 2020, the closing
sale price of our common stock as reported on Nasdaq was $1.16. You are urged to obtain current market quotations for the common stock.
We are an emerging growth company and a smaller reporting company under applicable Securities and Exchange Commission
rules and, as such, have elected to comply with certain reduced public company disclosure requirements for this prospectus and future filings. See Prospectus SummaryImplications of Being an Emerging Growth Company and a Smaller Reporting
Company.
Our business and investment in our common stock involve significant risks. These risks are described in the section
titled Risk Factors beginning on page 7 of this prospectus.
Neither the Securities and
Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.
The date of this prospectus is , 2020