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    <periodOfReport>2018-12-21</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001235007</issuerCik>
        <issuerName>ENDOCYTE INC</issuerName>
        <issuerTradingSymbol>ECYT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001241647</rptOwnerCik>
            <rptOwnerName>KOZIN MARC D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3000 KENT AVE., SUITE A1-100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WEST LAFAYETTE</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>47906</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
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            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

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            <transactionTimeliness>
                <value></value>
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            <transactionAmounts>
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                    <value>7800</value>
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                <transactionPricePerShare>
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    <derivativeTable>
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                <value>2018-12-21</value>
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                <transactionPricePerShare>
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                <transactionPricePerShare>
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            <expirationDate>
                <value>2024-05-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            </underlyingSecurity>
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        <derivativeTransaction>
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            <transactionDate>
                <value>2018-12-21</value>
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            <transactionTimeliness>
                <value></value>
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            <transactionAmounts>
                <transactionShares>
                    <value>13500</value>
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                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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            <expirationDate>
                <value>2025-05-14</value>
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                <transactionAcquiredDisposedCode>
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            <underlyingSecurity>
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        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
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                <value></value>
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                <transactionShares>
                    <value>19500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.73</value>
                    <footnoteId id="F3"/>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            <exerciseDate>
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            <expirationDate>
                <value>2027-05-04</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
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                <directOrIndirectOwnership>
                    <value>D</value>
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            <securityTitle>
                <value>Stock Option (right to buy)</value>
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                <value>10.81</value>
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                <value>2018-12-21</value>
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                <value></value>
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                    <value>19500</value>
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                <transactionPricePerShare>
                    <value>13.19</value>
                    <footnoteId id="F4"/>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                    <value>0</value>
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    <footnotes>
        <footnote id="F1">Pursuant to the Agreement and Plan of Merger, dated as of October 17, 2018 (the &quot;Merger Agreement&quot;), by and among Endocyte, Inc. (the &quot;Company&quot;), Novartis AG (&quot;Novartis&quot;) and Edinburgh Merger Corporation, a wholly owned subsidiary of Novartis (&quot;Merger Sub&quot;), at the effective time (the &quot;Effective Time&quot;) of the merger of Merger Sub with and into the Company, which Effective Time occurred on December 21, 2018, each share of Company common stock was converted into the right to receive an amount in cash equal to $24.00, without interest and less any applicable withholding taxes.</footnote>
        <footnote id="F2">This restricted stock unit (&quot;RSU&quot;) award provided for vesting and settlement 100% on the business day prior to the Company's annual stockholder meeting following May 3, 2018 in the form of one share of Company common stock for each RSU. Pursuant to the Merger Agreement, at the Effective Time, each RSU outstanding immediately prior to the Effective Time was canceled and converted into the right to receive an amount in cash, without interest, equal to $24.00, multiplied by the number of shares of Company common stock subject to such RSU, less any applicable withholding taxes.</footnote>
        <footnote id="F3">This Company stock option was fully vested immediately prior to the Effective Time. Pursuant to the Merger Agreement, at the Effective Time, each Company stock option that was outstanding immediately prior to the Effective Time was canceled and converted into the right to receive an amount in cash, without interest, equal to the excess of $24.00 over the exercise price with respect to such stock option, multiplied by the number of shares of Company common stock subject to such stock option, less any applicable withholding taxes.</footnote>
        <footnote id="F4">This Company stock option was scheduled to vest 100% on the business day prior to the Company's annual stockholder meeting following May 3, 2018. Pursuant to the Merger Agreement, at the Effective Time, each Company stock option that was outstanding immediately prior to the Effective Time was canceled and converted into the right to receive an amount in cash, without interest, equal to the excess of $24.00 over the exercise price with respect to such stock option, multiplied by the number of shares of Company common stock subject to such stock option, less any applicable withholding taxes.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael A. Sherman, Attorney-in-Fact for Marc D. Kozin (power of attorney previously filed)</signatureName>
        <signatureDate>2018-12-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
