Exhibit 4.5


 


DESCRIPTION OF THE REGISTRANT’S
SECURITIES


REGISTERED PURSUANT TO SECTION 12 OF
THE SECURITIES


EXCHANGE ACT OF 1934


 


Humanigen, Inc. (“we,” “our,” “us,”
or the “Company”) has the following securities described below registered under Section 12 of the Securities Exchange
Act of 1934, as amended (the “Exchange Act”). The following summary of the terms of our capital stock is based upon
our Amended and Restated Certificate of Incorporation (“Charter”) and our Second Amended and Restated Bylaws (“Bylaws”),
in each case as amended and in effect on the date hereof. This summary does not purport to be complete and is subject to, and is
qualified in its entirety by express reference to, the applicable provisions of our Charter and our Bylaws, which are filed as
exhibits to our Annual Report on Form 10-K, of which this Exhibit 4.5 is a part, and are incorporated by reference herein. We encourage
you to read our Charter, our Bylaws, and the applicable provisions of the Delaware General Corporation Law (the “DGCL”)
for more information.


 


DESCRIPTION OF SECURITIES


 


Authorized
Capital Stock


 


Our authorized capital stock consists of
250,000,000 shares, of which 225,000,000 shares shall be common stock, par value $0.001 per share, and 25,000,000 shares shall
be preferred stock, par value of $0.001 per share. On September 11, 2020, we completed a 1-for-5 reverse split of our outstanding
shares of common stock. The reverse stock split had no effect on the number of authorized shares of common or preferred stock,
or on the stated par value per share of our common stock.


 


As of March 5, 2021 there were 53,482,364
shares of common stock outstanding, held by 40 stockholders of record, although we believe that there may be a significantly larger
number of beneficial owners of our common stock. We derived the number of stockholders by reviewing the listing of outstanding
common stock recorded by our transfer agent as of March 5, 2021.


 


Common Stock


 


Each holder of
our common stock is entitled to one vote for each share of common stock held on all matters submitted to a vote of the stockholders.
Holders of our common stock are entitled to receive ratably the dividends, if any, as may be declared from time to time by the
board of directors out of funds legally available therefor. If there is a liquidation, dissolution or winding up of our company,
holders of our common stock would be entitled to share in our assets remaining after the payment of liabilities. Holders of our
common stock have no preemptive or conversion rights or other subscription rights, and there are no redemption or sinking fund
provisions applicable to the common stock. The outstanding shares of common stock are fully paid and non-assessable. Holders of
shares of our common stock are not liable for further calls or to assessments by us. The rights, powers, preferences and privileges
of holders of common stock are subordinate to, and may be adversely affected by, the rights of the holders of shares of any series
of preferred stock which our board of directors may designate and issue in the future.


 


As of March 5, 2021,
no shares of preferred stock were outstanding. Shares of preferred stock may be issued from time to time in one or more series,
each of which will have such distinctive designation or title as shall be determined by our Board prior to the issuance of any
shares thereof. Preferred stock will have such voting powers, full or limited, or no voting powers, and such preferences, privileges
and relative, participating, optional or other special rights and such qualifications, limitations or restrictions thereof, including
dividend rights, conversion rights, voting rights, redemption rights, liquidation preference, sinking fund terms and the number
of shares constituting any series or the designation of any series, as shall be stated in such resolution or resolutions providing
for the issue of such class or series of preferred stock as may be adopted from time to time by the Board prior to the issuance
of any shares thereof.


 






    	 	 	 



    	 



    

 


The
issuance of preferred stock could adversely affect the rights of the holders of common stock and, therefore, reduce the market
price of the common stock. It is not possible to state the actual effect of the issuance of any shares of preferred stock on the
rights of holders of the common stock until the Board determines the specific rights of the holders of the preferred stock; however,
these effects may include:


 


	 	·	Restricting dividends on the common stock;


 


	 	·	Diluting the voting power of the common stock;


 


	 	·	Impairing the liquidation rights of the common stock; or


 


	 	·	Delaying, deterring or preventing a change in control of the Company.


 


 


Certain of our
existing holders of common stock have the right to require us to register their shares of common stock under the Securities
Act of 1933, as amended, in specified circumstances.


 


The transfer agent
and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent’s address is 250 Royall Street,
Canton, Massachusetts 02021 and its telephone number is (800) 662-7232.


 


Dividend Policy


 


We have never
declared or paid any cash dividends on our capital stock, and we do not currently intend to pay any cash dividends on our common
stock for the foreseeable future. We expect to retain future earnings, if any, to fund the development and growth of our business.
Any future determination to pay dividends on our common stock will be at the discretion of our board of directors and will depend
upon, among other factors, our financial condition, operating results, current and anticipated cash needs, plans for expansion
and other factors that our board of directors may deem relevant.


 


Anti-Takeover
Provisions of Our Charter Documents and Delaware Law


 


Some provisions
of our Charter, our Bylaws and the DGCL could make it more difficult to acquire our company by means of a tender offer, a proxy
contest, or otherwise.


 


Our Bylaws establish
advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, other
than nominations made by or at the direction of our board of directors or a committee of our board of directors. These procedures
provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at
which the action is to be taken. Generally, for a proposal to be timely submitted for consideration at an annual meeting, notice
must be delivered to our secretary not less than 90 days nor more than 120 days prior to the first anniversary date of the annual
meeting for the preceding year. Our Bylaws specify the requirements as to form and content of all stockholders’ notices.
These provisions might preclude our stockholders from bringing matters before our annual meeting of stockholders or from making
nominations for directors at our annual meeting of stockholders if the proper procedures are not followed.


 


Our Charter and
Bylaws both provide that vacancies on our board of directors, including newly created directorships, may be filled only by a majority
vote of directors then in office, and directors so chosen shall hold office for a term expiring at the next annual meeting of stockholders
or until such director’s successor shall have been duly elected and qualified. Accordingly, the board of directors could
prevent any stockholder from filling the new directorships with such stockholder’s own nominee.


 


Our Charter provides
that, unless we consent in writing to the selection of an alternative forum, the Delaware
Court of Chancery shall be the sole and exclusive forum for (i) any derivative action or proceeding brought on our behalf,
(ii) any action asserting a claim of breach of a fiduciary duty owed by any of our current or former directors, officers or other
employees to us or our stockholders, (iii) any action asserting a claim arising pursuant to any provision of the DGCL, our Charter
or our Bylaws, or (iv) any action asserting a claim against us governed by the internal affairs doctrine; in all cases subject
to the court having personal jurisdiction over the indispensable parties named as defendants. This choice of forum provision may
limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors,
officers or other employees, which may discourage such lawsuits against us and our directors, officers and other employees.


 






    	 	 	 



    	 



    

 


Delaware Anti-Takeover
Law


 


We are subject
to Section 203 of the DGCL which contains anti-takeover provisions. In general, Section 203 prohibits a publicly held Delaware
corporation from engaging in a business combination with an interested stockholder for a period of three years following the date
that the person became an interested stockholder, unless the business combination or the transaction in which the person became
an interested stockholder is approved in a prescribed manner. Generally, a business combination includes a merger, asset or stock
sale or another transaction resulting in a financial benefit to the interested stockholder. An interested stockholder is a person
who, together with affiliates and associates, owns 15% or more of the corporation’s voting stock. The existence of this provision
may have an anti-takeover effect with respect to transactions that are not approved in advance by our board of directors, including
discouraging attempts that might result in a premium over the market price for the shares of common stock held by stockholders.


 


No Cumulative
Voting


 


Under the DGCL,
cumulative voting for the election of directors is not permitted unless a corporation’s certificate of incorporation authorizes
cumulative voting. Our Charter does not provide for cumulative voting in the election of directors. Cumulative voting allows a
minority stockholder to vote a portion or all of its shares for one or more candidates for seats on our board of directors. Without
cumulative voting, a minority stockholder will not be able to gain as many seats on our board of directors based on the number
of shares of our stock the stockholder holds as compared to the number of seats the stockholder would be able to gain if cumulative
voting were permitted. The absence of cumulative voting makes it more difficult for a minority stockholder to gain a seat on our
board of directors to influence our board’s decision regarding a takeover.


 


Stockholder
Action by Written Consent


 


The DGCL generally
provides that the affirmative vote of a majority of the shares entitled to vote on such matter is required to amend a corporation’s
certificate of incorporation or bylaws, unless a corporation’s certificate of incorporation or bylaws requires a greater
percentage. Our Charter permits our board of directors to amend or repeal most provisions of our Bylaws by majority vote. Generally,
our Charter may be amended by holders of a majority of the voting power of the then outstanding shares of our capital stock entitled
to vote. The stockholder vote or consent with respect to an amendment of our Charter or Bylaws would be in addition to any separate
class vote that might in the future be required under the terms of any series of preferred stock that might be outstanding at the
time such a proposed amendment were submitted to stockholders. The DGCL and the provisions of our Bylaws generally permit stockholders
owning the requisite percentage of shares of common stock necessary to approve an amendment to our Charter and Bylaws to act by
written consent in lieu of a meeting of our stockholders.


 


Limitation
of Liability and Indemnification of Officers and Directors


 


Our Bylaws provide
indemnification, including advancement of expenses, to the fullest extent permitted under applicable law to any person made or
threatened to be made a party to any threatened, pending, or completed action, suit, or proceeding, whether civil, criminal, administrative,
or investigative by reason of the fact that such person is or was a director or officer of the company, or is or was serving at
our request as a director or officer of another corporation, partnership, joint venture, trust, or other enterprise, including
service with respect to an employee benefit plan. In addition, our Charter provides that our directors will not be personally liable
to us or our stockholders for monetary damages for breaches of their fiduciary duty as directors, unless they violated their duty
of loyalty to us or our shareholders, acted in bad faith, knowingly or intentionally violated the law, authorized illegal dividends
or redemptions or derived an improper personal benefit from their action as directors. This provision does not limit or eliminate
our rights or the rights of any stockholder to seek nonmonetary relief such as an injunction or rescission in the event of a breach
of a director’s duty of care. In addition, this provision does not limit the directors’ responsibilities under the
DGCL or any other laws, such as the federal securities laws. We have obtained insurance that insures our directors and officers
against certain losses and which insures us against our obligations to indemnify the directors and officers. We also have entered
into indemnification agreements with our directors and executive officers.