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    <dei:DocumentType contextRef="P01_01_2024To12_31_2024" id="hidden143853701">DEF 14A</dei:DocumentType>
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    <dei:EntityCentralIndexKey contextRef="P01_01_2024To12_31_2024" id="ixv-6476">0001754068</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="P01_01_2024To12_31_2024" id="ixv-6486">Kalaris Therapeutics, Inc.</dei:EntityRegistrantName>
    <ecd:InsiderTrdPoliciesProcAdoptedFlag contextRef="P01_01_2024To12_31_2024" id="ixv-6490">true</ecd:InsiderTrdPoliciesProcAdoptedFlag>
    <ecd:AwardTmgMnpiDiscTextBlock contextRef="P01_01_2024To12_31_2024" id="ixv-4089">&lt;div id="toc830103_35" style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: &amp;quot;Times New Roman&amp;quot;;"&gt;&lt;div style="font-weight:bold;display:inline;"&gt;&lt;div style="font-style: italic; letter-spacing: 0px; top: 0px;display:inline;"&gt;Equity Grant Timing &lt;/div&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"&gt;The AlloVir compensation committee generally granted equity awards on an annual basis. In addition, eligible employees, including the AlloVir named executive officers, could have voluntarily enrolled in our 2020 Employee Stock Purchase Plan, or the ESPP, and received an option to purchase shares at a discount using payroll deductions accumulated during the prior six months, which purchase dates occurred in June and December. During 2024, the AlloVir compensation committee did not take into account any material nonpublic information when determining the timing and terms of equity incentive awards, and AlloVir did not time the disclosure of material nonpublic information for the purpose of affecting the value of executive compensation. During 2024, AlloVir did not grant stock options to the AlloVir named executive officers during any period beginning four business days before and ending one business day after the filing or furnishing of a Form &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;10-Q,&lt;/div&gt; &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;10-K&lt;/div&gt; or &lt;div style="white-space: nowrap; letter-spacing: 0px; top: 0px;display:inline;"&gt;8-K&lt;/div&gt; that disclosed material nonpublic information. &lt;/div&gt;</ecd:AwardTmgMnpiDiscTextBlock>
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