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      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 14pt; font-weight: bold;">UNITED STATES</div>

      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 14pt; font-weight: bold;">SECURITIES AND EXCHANGE COMMISSION</div>

      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 12pt; font-weight: bold;">WASHINGTON, D.C. 20549</div>

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      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 18pt; font-weight: bold;">FORM <ix:nonNumeric name="dei:DocumentType" id="Fact_b64af3bd283b41038957c3577f549eb4" contextRef="c20220203to20220203">8-K</ix:nonNumeric></div>

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      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">CURRENT REPORT</div>

      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Pursuant to Section 13 or 15(d)</div>

      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">of the Securities Exchange Act of 1934</div>

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      <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">(Address of principal executive offices) (Zip Code)</div>

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        <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Not Applicable</div>

        <div style="text-align: center; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">(Former name or former address, if changed since last report)</div>

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      <div style="text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following
        provisions:</div>

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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

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    <td style="width: 28pt; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt;"><ix:nonNumeric name="dei:SolicitingMaterial" id="Fact_b818b1bafc054afa852a47cd681b5381" contextRef="c20220203to20220203" format="ixt-sec:boolballotbox">&#x2610;</ix:nonNumeric><br />
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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

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    <td style="width: 28pt; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt;"><ix:nonNumeric name="dei:PreCommencementTenderOffer" id="Fact_63cc73aaa4f74df08d8659692c1d543b" contextRef="c20220203to20220203" format="ixt-sec:boolballotbox">&#x2610;</ix:nonNumeric><br />
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    <td style="width: auto; vertical-align: top; text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">
              <div>Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))</div>
            </td>

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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

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    <td style="width: 28pt; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt;"><ix:nonNumeric name="dei:PreCommencementIssuerTenderOffer" id="Fact_899344bb7b8740fbbcef1fadb5415518" contextRef="c20220203to20220203" format="ixt-sec:boolballotbox">&#x2610;</ix:nonNumeric><br />
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    <td style="width: auto; vertical-align: top; text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">
              <div>Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))</div>
            </td>

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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: center; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Securities registered pursuant to Section 12(b) of the Act:</div>

      <div style="text-align: center; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;"> <br />
      </div>

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    <td style="width: 42%; vertical-align: bottom; border-bottom: 2px solid rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">
              <div style="text-align: center; color: rgb(0, 0, 0); font-weight: bold;">Title of each class</div>
            </td>

    <td style="width: 0.58%; vertical-align: bottom; font-family: 'Times New Roman'; font-size: 10pt;">&#160;</td>

    <td style="width: 14.04%; vertical-align: bottom; border-bottom: 2px solid rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">
              <div style="text-align: center; color: rgb(0, 0, 0); font-weight: bold;">Trading Symbol(s)</div>
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    <td style="width: 0.58%; vertical-align: bottom; font-family: 'Times New Roman'; font-size: 10pt;">&#160;</td>

    <td style="width: 41.96%; vertical-align: bottom; border-bottom: 2px solid rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">
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    <td style="width: 42%; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt;">
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    <td style="width: 0.58%; vertical-align: bottom; font-family: 'Times New Roman'; font-size: 10pt;">&#160;</td>

    <td style="width: 14.04%; vertical-align: bottom; font-family: 'Times New Roman'; font-size: 10pt;">
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    <td style="width: 0.58%; vertical-align: bottom; font-family: 'Times New Roman'; font-size: 10pt;">&#160;</td>

    <td style="width: 41.96%; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt;">
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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (&#167;230.405 of this chapter) or Rule 12b-2
        of the Securities Exchange Act of 1934 (&#167;240.12b-2 of this chapter).</div>

      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

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              <div>Emerging growth company</div>
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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised
        financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.&#160; &#9744;</div>

      <div style="text-align: left; font-family: 'Times New Roman'; font-size: 10pt;"><br />
      </div>

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    <td style="width: 45pt; vertical-align: top; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Item 8.01</td>

    <td style="width: auto; vertical-align: top; text-align: justify; font-family: 'Times New Roman'; font-size: 10pt;">
              <div style="font-weight: bold;">Other Events.</div>
            </td>

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      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: justify; text-indent: 36pt; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">As previously disclosed on December 13, 2021, Arena Pharmaceuticals, Inc., a Delaware corporation (the &#8220;Company&#8221; or &#8220;Arena&#8221;),
        Pfizer Inc., a Delaware corporation (&#8220;Pfizer&#8221;), and Antioch Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Pfizer (&#8220;Merger Sub&#8221;), entered into an Agreement and Plan of Merger, dated as of December 12, 2021 (the &#8220;Merger
        Agreement&#8221;), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as a wholly owned subsidiary of Pfizer (the &#8220;Merger&#8221;).</div>

      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: justify; text-indent: 18pt; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">The Merger is conditioned on the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust
        Improvements Act of 1976, as amended (the &#8220;HSR Act&#8221;). On January 4, 2022, Arena and Pfizer each filed a Notification and Report Form with respect to the Merger. Pfizer voluntarily withdrew its HSR Act filing on February 3, 2022, refiling on
        February 7, 2022. The withdrawal and refiling are procedural steps to provide the Federal Trade Commission with an additional 30 days to complete its review of the proposed Merger. The waiting period with respect to the notification and report
        forms under the HSR Act is now scheduled to expire at 11:59 p.m., Eastern Time, on March 9, 2022, unless extended or earlier terminated.</div>

      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: justify; text-indent: 18pt; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">The proposed Merger is targeted to close in the first half of 2022, subject to applicable antitrust clearances and other
        customary closing conditions.</div>

      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: justify; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Cautionary Statement Regarding Forward-Looking Statements</div>

      <div style="font-family: 'Times New Roman'; font-size: 10pt;">&#160;</div>

      <div style="text-align: justify; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: 10pt;">This communication and any documents referred to in this communication contain certain forward-looking statements within the meaning of the
        federal securities laws with respect to the proposed transaction between Pfizer and Arena, including, but not limited to, statements regarding the expected benefits of the proposed transaction and the anticipated timing of the proposed transaction,
        strategies, objectives and the products and markets of each company. These forward-looking statements generally are identified by the words &#8220;believe,&#8221; &#8220;predict,&#8221; &#8220;target,&#8221; &#8220;contemplate,&#8221; &#8220;potential,&#8221; &#8220;project,&#8221; &#8220;expect,&#8221; &#8220;anticipate,&#8221; &#8220;estimate,&#8221;
        &#8220;intend,&#8221; &#8220;strategy,&#8221; &#8220;future,&#8221; &#8220;opportunity,&#8221; &#8220;plan,&#8221; &#8220;may,&#8221; &#8220;should,&#8221; &#8220;will,&#8221; &#8220;would,&#8221; &#8220;could,&#8221; &#8220;will be,&#8221; &#8220;will continue,&#8221; &#8220;will likely result,&#8221; and similar expressions. Forward-looking statements are predictions, projections and other
        statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Many factors could cause actual future events to differ materially from the forward-looking statements
        in this communication, including but not limited to: (i) the risk that the proposed transaction may not be completed in a timely manner or at all, (ii) the failure to satisfy the conditions to the consummation of the proposed transaction, including
        the receipt of certain governmental and regulatory approvals, (iii) the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement, (iv) the effect of the announcement or pendency of the
        proposed transaction on Arena&#8217;s business relationships, operating results, and business generally, (v) risks that the proposed transaction disrupts current plans and operations of Arena or Pfizer and potential difficulties in Arena employee
        retention as a result of the proposed transaction, (vi) risks related to diverting management&#8217;s attention from Arena&#8217;s ongoing business operations, and (vii) the outcome of any legal proceedings that may be instituted against Pfizer or against
        Arena related to the Merger Agreement or the proposed transaction. The risks and uncertainties may be amplified by the COVID-19 pandemic (and related variants), which has caused significant economic uncertainty. The extent to which the COVID-19
        pandemic (and related variants) impacts Arena&#8217;s businesses, operations, and financial results, including the duration and magnitude of such effects, will depend on numerous factors, which are unpredictable, including, but not limited to, the
        duration and spread of the outbreak, its severity, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. The foregoing list of factors is not exhaustive. You
        should carefully consider the foregoing factors and the other risks and uncertainties that affect the businesses of Pfizer and Arena described in the &#8220;Risk Factors&#8221; section of Arena&#8217;s most recent Annual Report on Form 10-K, Quarterly Reports on
        Form 10-Q and other documents filed by Arena from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the
        forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and Arena assumes no obligation to, and does not intend to, update or
        revise these forward-looking statements, whether as a result of new information, future events, or otherwise, unless required by law. Arena gives no assurance that it will achieve its expectations.</div>

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      <div style="text-align: center; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">SIGNATURES</div>

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      <div style="text-align: justify; text-indent: 36pt; font-family: 'Times New Roman'; font-size: 10pt;">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the
        undersigned hereunto duly authorized.</div>

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              <div style="text-align: left; font-weight: bold;">ARENA PHARMACEUTICALS, INC.</div>
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              <div style="text-align: left;">By:</div>
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              <div style="text-align: left; margin-left: 0.85pt;">/s/ Amit D. Munshi</div>
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    <td style="width: 47%; vertical-align: top;">
              <div style="text-align: left; margin-left: 1.95pt; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">Amit D. Munshi</div>
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              <div style="text-align: left; margin-left: 1.95pt; font-family: 'Times New Roman'; font-size: 10pt; font-weight: bold;">President and Chief Executive Officer</div>
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              <div style="text-align: left; font-family: 'Times New Roman'; font-size: 10pt;">Date: <span style="color: rgb(0, 0, 0);">February 7</span>, 2022</div>
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM
8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported):
February 3, 2022
Arena Pharmaceuticals, Inc.
(Exact Name of Registrant as Specified in its Charter)
Delaware
000-31161
23-2908305
(State or other Jurisdiction of Incorporation)
(Commission File Number)
(IRS Employer Identification No.)
136 Heber Avenue
,
Suite 204
Park City
,
Utah
84060
(Address of principal executive offices) (Zip Code)
(
858
)
453-7200
Registrant's telephone number, including area code
Not Applicable
(Former name or former address, if changed since last report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following
        provisions:
☐
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Securities registered pursuant to Section 12(b) of the Act:
Title of each class
Trading Symbol(s)
Name of each exchange on which registered
Common Stock, par value $0.0001 per share
ARNA
The Nasdaq Global Select Market
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2
        of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
☐
Emerging growth company
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised
        financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐
Item 8.01
Other Events.
As previously disclosed on December 13, 2021, Arena Pharmaceuticals, Inc., a Delaware corporation (the "Company" or "Arena"),
        Pfizer Inc., a Delaware corporation ("Pfizer"), and Antioch Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Pfizer ("Merger Sub"), entered into an Agreement and Plan of Merger, dated as of December 12, 2021 (the "Merger
        Agreement"), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as a wholly owned subsidiary of Pfizer (the "Merger").
The Merger is conditioned on the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust
        Improvements Act of 1976, as amended (the "HSR Act"). On January 4, 2022, Arena and Pfizer each filed a Notification and Report Form with respect to the Merger. Pfizer voluntarily withdrew its HSR Act filing on February 3, 2022, refiling on
        February 7, 2022. The withdrawal and refiling are procedural steps to provide the Federal Trade Commission with an additional 30 days to complete its review of the proposed Merger. The waiting period with respect to the notification and report
        forms under the HSR Act is now scheduled to expire at 11:59 p.m., Eastern Time, on March 9, 2022, unless extended or earlier terminated.
The proposed Merger is targeted to close in the first half of 2022, subject to applicable antitrust clearances and other
        customary closing conditions.
Cautionary Statement Regarding Forward-Looking Statements
This communication and any documents referred to in this communication contain certain forward-looking statements within the meaning of the
        federal securities laws with respect to the proposed transaction between Pfizer and Arena, including, but not limited to, statements regarding the expected benefits of the proposed transaction and the anticipated timing of the proposed transaction,
        strategies, objectives and the products and markets of each company. These forward-looking statements generally are identified by the words "believe," "predict," "target," "contemplate," "potential," "project," "expect," "anticipate," "estimate,"
        "intend," "strategy," "future," "opportunity," "plan," "may," "should," "will," "would," "could," "will be," "will continue," "will likely result," and similar expressions. Forward-looking statements are predictions, projections and other
        statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Many factors could cause actual future events to differ materially from the forward-looking statements
        in this communication, including but not limited to: (i) the risk that the proposed transaction may not be completed in a timely manner or at all, (ii) the failure to satisfy the conditions to the consummation of the proposed transaction, including
        the receipt of certain governmental and regulatory approvals, (iii) the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement, (iv) the effect of the announcement or pendency of the
        proposed transaction on Arena's business relationships, operating results, and business generally, (v) risks that the proposed transaction disrupts current plans and operations of Arena or Pfizer and potential difficulties in Arena employee
        retention as a result of the proposed transaction, (vi) risks related to diverting management's attention from Arena's ongoing business operations, and (vii) the outcome of any legal proceedings that may be instituted against Pfizer or against
        Arena related to the Merger Agreement or the proposed transaction. The risks and uncertainties may be amplified by the COVID-19 pandemic (and related variants), which has caused significant economic uncertainty. The extent to which the COVID-19
        pandemic (and related variants) impacts Arena's businesses, operations, and financial results, including the duration and magnitude of such effects, will depend on numerous factors, which are unpredictable, including, but not limited to, the
        duration and spread of the outbreak, its severity, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. The foregoing list of factors is not exhaustive. You
        should carefully consider the foregoing factors and the other risks and uncertainties that affect the businesses of Pfizer and Arena described in the "Risk Factors" section of Arena's most recent Annual Report on Form 10-K, Quarterly Reports on
        Form 10-Q and other documents filed by Arena from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the
        forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and Arena assumes no obligation to, and does not intend to, update or
        revise these forward-looking statements, whether as a result of new information, future events, or otherwise, unless required by law. Arena gives no assurance that it will achieve its expectations.
1
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the
        undersigned hereunto duly authorized.
ARENA PHARMACEUTICALS, INC.
By:
/s/ Amit D. Munshi
Amit D. Munshi
President and Chief Executive Officer
Date:
February 7
, 2022
2