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        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001789632</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001786205</issuerCik>
            <issuerName>ARCELLX INC</issuerName>
            <secFileNumber>001-41259</secFileNumber>
            <issuerAddress>
                <ns2:street1>800 Bridge Parkway</ns2:street1>
                <ns2:city>Redwood City</ns2:city>
                <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                <ns2:zipCode>94065</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>2403270603</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>CHRISTOPHER HEERY</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>48907</noOfUnitsSold>
            <aggregateMarketValue>3393167.66</aggregateMarketValue>
            <noOfUnitsOutstanding>53755679</noOfUnitsOutstanding>
            <approxSaleDate>08/26/2024</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>08/26/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>52556</amountOfSecuritiesAcquired>
            <paymentDate>08/26/2024</paymentDate>
            <natureOfPayment>Cash</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/16/2024</saleDate>
            <amountOfSecuritiesSold>5450</amountOfSecuritiesSold>
            <grossProceeds>354526.32</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/01/2024</saleDate>
            <amountOfSecuritiesSold>20000</amountOfSecuritiesSold>
            <grossProceeds>1208434.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/16/2024</saleDate>
            <amountOfSecuritiesSold>10901</amountOfSecuritiesSold>
            <grossProceeds>711853.28</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/12/2024</saleDate>
            <amountOfSecuritiesSold>1780</amountOfSecuritiesSold>
            <grossProceeds>107175.22</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/11/2024</saleDate>
            <amountOfSecuritiesSold>3671</amountOfSecuritiesSold>
            <grossProceeds>220301.85</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/01/2024</saleDate>
            <amountOfSecuritiesSold>20000</amountOfSecuritiesSold>
            <grossProceeds>1107762.64</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER R HEERY</name>
                <address>
                    <ns2:street1>800 Bridge Parkway</ns2:street1>
                    <ns2:city>Redwood City</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94065</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>06/12/2024</saleDate>
            <amountOfSecuritiesSold>20000</amountOfSecuritiesSold>
            <grossProceeds>1102668.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <remarks>The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.&#13;
</remarks>
        <noticeSignature>
            <noticeDate>08/26/2024</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>12/22/2023</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Christopher Heery</signature>
        </noticeSignature>
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144
0001789632
XXXXXXXX
LIVE
0001786205
ARCELLX INC
001-41259
800 Bridge Parkway
Redwood City
CA
94065
2403270603
CHRISTOPHER HEERY
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
48907
3393167.66
53755679
08/26/2024
NASDAQ
Common
08/26/2024
Exercise of Stock Options
Issuer
N
52556
08/26/2024
Cash
N
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
08/16/2024
5450
354526.32
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
08/01/2024
20000
1208434.00
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
07/16/2024
10901
711853.28
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
07/12/2024
1780
107175.22
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
07/11/2024
3671
220301.85
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
07/01/2024
20000
1107762.64
10b5-1 Sales for CHRISTOPHER R HEERY
800 Bridge Parkway
Redwood City
CA
94065
Common
06/12/2024
20000
1102668.00
The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.
08/26/2024
12/22/2023
/s/ Christopher Heery