The information in this base prospectus is not complete and may be changed. We may not
sell these securities until the registration statement filed with the U.S. Securities and Exchange Commission is effective. This base prospectus is not an offer to sell these securities, and we are not soliciting offers to buy these securities, in
any state or other jurisdiction where the offer or sale is not permitted.
SUBJECT TO COMPLETION, DATED AUGUST 14, 2024
PROSPECTUS
$250,000,000
Common Stock
Preferred Stock
Debt
Securities
Warrants
Units
From time to
time, we may offer and sell, in one or more offerings, in amounts, at prices and on terms determined at the time of any such offering, common stock, preferred stock, debt securities, warrants, either individually or in units, with a total value of
up to $250,000,000.
This base prospectus describes some of the general terms that may apply to these securities. Each time securities are
sold, the specific terms and amounts of the securities being offered, and any other information relating to the specific offering will be set forth in a supplement to this base prospectus. We may also authorize one or more free writing
prospectuses to be provided to you in connection with these offerings. A prospectus supplement and any related free writing prospectus may also supplement, update or amend information contained in this base prospectus. You should read this base
prospectus, any applicable prospectus supplement and related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.
THIS BASE PROSPECTUS MAY NOT BE USED TO OFFER AND SELL SECURITIES UNLESS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.
Our common stock trades on The Nasdaq Capital Market under the symbol DRRX. On August 12, 2024, the last reported sale price
of the common stock on The Nasdaq Capital Market was $1.43 per share.
We may offer the securities from time to time in amounts, at prices
and on terms determined at the time of offering. We may offer and sell the securities directly to you, through agents we select or through underwriters and dealers we select on a continuous or delayed basis. The accompanying prospectus supplement
will provide the specific terms of the plan of distribution. If we use agents, underwriters or dealers to sell the securities, we will name them and describe their compensation in the prospectus supplement. The price to the public of such securities
and the net proceeds we expect to receive from such sale will also be set forth in the prospectus supplement.
As of August 12, 2024,
the aggregate market value of our outstanding common stock held by non-affiliates, or public float, was approximately $44.0 million, based on 31,039,381 shares of outstanding common stock, of which 267,066
shares were held by affiliates, and a price of $1.43 per share, which was the price at which our common stock was last sold on The Nasdaq Capital Market on August 12, 2024. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities registered on the registration statement, of which this base prospectus and the accompanying prospectus supplement form a part, in a public primary offering with a value
exceeding more than one-third of our public float in any 12-month period so long as our public float remains below $75 million (the Baby Shelf
Limitation). After giving effect to the Baby Shelf limitation and the current public float of our common stock, we currently may offer and sell shares of our common stock having an aggregate offering price of up to approximately $18.1 million.
As of August 12, 2024, we have not sold any securities pursuant to General Instruction I.B.6 of Form S-3 during the prior 12-calendar-month period that ends on and
includes the date of this base prospectus.
We are a smaller reporting company under the federal securities laws and, as such,
are subject to reduced public company reporting requirements. See Prospectus SummaryImplications of Being a Smaller Reporting Company.
Investing in our securities involves a high degree of risk. You should carefully read and consider the risk factors described in this base
prospectus, any accompanying prospectus supplement, any related free writing prospectus and in the documents incorporated by reference into this base prospectus. See Risk Factors beginning on page 4.
Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these
securities or determined if this base prospectus is truthful or complete. Any representation to the contrary is a criminal offense.
The date of
this base prospectus is , 2024