<?xml version="1.0" encoding="US-ASCII"?>
<!-- DFIN New ActiveDisclosure (SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2025-04-21T17:42:44.4057+00:00 -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema targetNamespace="http://www.apellis.com/20250421" attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:ecd-sub="http://xbrl.sec.gov/ecd-sub/2024" xmlns:ecd="http://xbrl.sec.gov/ecd/2024" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:us-gaap="http://fasb.org/us-gaap/2024" xmlns:dei="http://xbrl.sec.gov/dei/2024" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:apls="http://www.apellis.com/20250421" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink">
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance"/>
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase"/>
  <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/ecd/2024/ecd-sub-2024.xsd" namespace="http://xbrl.sec.gov/ecd-sub/2024"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2024/dei-2024.xsd" namespace="http://xbrl.sec.gov/dei/2024"/>
  <xsd:import schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd" namespace="http://www.xbrl.org/dtr/type/2024-01-31"/>
  <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd" namespace="http://fasb.org/us-gaap/2024"/>
  <xsd:import schemaLocation="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd" namespace="http://xbrl.sec.gov/ecd/2024"/>
  <xsd:annotation>
    <xsd:appinfo>
      <link:roleType roleURI="http://www.apellis.com/20250421/taxonomy/role/DocumentDocumentAndEntityInformation" id="DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbase id="lnk">
        <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple"/>
        <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple"/>
        <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple"/>
        <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple"/>
        <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple"/>
        <link:arcroleRef arcroleURI="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:href="http://www.xbrl.org/lrr/arcrole/esma-arcrole-2018-11-21.xsd#wider-narrower" xlink:type="simple"/>
        <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:href="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd#PvpAdjustmentsOnly" xlink:type="simple"/>
        <link:roleRef roleURI="http://www.apellis.com/20250421/taxonomy/role/DocumentDocumentAndEntityInformation" xlink:href="apls-20250421.xsd#DocumentDocumentAndEntityInformation" xlink:type="simple"/>
        <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/PvpDisclosure" xlink:href="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd#PvpDisclosure" xlink:type="simple"/>
        <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:title="labelLink" xlink:type="extended">
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_SCTOptionAwardsColumnValueMember" xlink:label="apls_SCTOptionAwardsColumnValueMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember" xlink:label="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey" xlink:label="dei_EntityCentralIndexKey"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember" xlink:label="apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CoverAbstract" xlink:label="dei_CoverAbstract"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember" xlink:label="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag" xlink:label="dei_AmendmentFlag"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember" xlink:label="apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember" xlink:label="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember" xlink:label="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType" xlink:label="dei_DocumentType"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember" xlink:label="apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember" xlink:label="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_TotalAdjustmentsForEquityAwardsMember" xlink:label="apls_TotalAdjustmentsForEquityAwardsMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" xlink:label="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_ExcessFairValueForEquityAwardModificationsMember" xlink:label="apls_ExcessFairValueForEquityAwardModificationsMember"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_SCTStockAwardsColumnValueMember" xlink:label="apls_SCTStockAwardsColumnValueMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityRegistrantName" xlink:label="dei_EntityRegistrantName"/>
          <link:loc xlink:type="locator" xlink:href="apls-20250421.xsd#apls_NonPeoName" xlink:label="apls_NonPeoName"/>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTOptionAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">S C T Option Awards Column Value [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTOptionAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">S c t option awards column value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTOptionAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">SCT "Option Awards" Column Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Values at Vest Date for Awards Granted and Vested in Current Year [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair values at vest date for awards granted and vested in current year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Values at Vest Date for Awards Granted and Vested in Current Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Year-end Fair Value of Unvested Awards Granted in the Current Year [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Year-end fair value of unvested awards granted in the current year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Year-End Fair Value of Unvested Awards Granted in the Current Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">year-over-year change in fair value of equity awards granted in prior years that vested in the covered year [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">year-over-year change in fair value of equity awards granted in prior years that vested in the covered year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Year-Over-Year Change in Fair Value of Equity Awards Granted in Prior Years That Vested in the Covered Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">vesting date fair value of equity awards granted and vested in the covered year [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">vesting date fair value of equity awards granted and vested in the covered year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Vesting Date Fair Value of Equity Awards Granted and Vested in the Covered Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment for Grant Date Values in the Summary Compensation Table [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Adjustment for grant date values in the summary compensation table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustment for Grant Date Values in the Summary Compensation Table</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Difference in Fair Values Betweenprior Year-end Fair Values and Vest Date Fair Values for Awards Granted in Prior Years [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Difference in fair values betweenprior year-end fair values and vest date fair values for awards granted in prior years.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Difference in Fair Values Betweenprior Year-end Fair Values and Vest Date Fair Values for Awards Granted in Prior Years</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">year-over-year change in fair value of equity awards granted in prior years that are outstanding and unvested as of the covered year-end.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Year-Over-Year Change in Fair Value of Equity Awards Granted in Prior Years that are Outstanding and Unvested as of the Covered Year-End</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forfeitures During Current Yeare Qual to Prior Year-end Fair Value [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forfeitures during current yeare qual to prior year-end fair value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeitures During Current Yeare Qual to Prior Year-end Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Year-over-year Difference of Year-end Fair Values for Unvested Awards Granted in Prior Years [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Year-over-year difference of year-end fair values for unvested awards granted in prior years.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Year-Over-Year Difference of Year-End Fair Values for Unvested Awards Granted in Prior Years</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">fair value as of prior-year end of equity awards granted in prior years that failed to vest in the covered year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value as of Prior-Year End of Equity Awards Granted in Prior Years that Failed to vest in the Covered Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_TotalAdjustmentsForEquityAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Total Adjustments for Equity Awards [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_TotalAdjustmentsForEquityAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Total adjustments for equity awards.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_TotalAdjustmentsForEquityAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total Adjustments for Equity Awards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">year-end fair value of equity awards granted in the covered year that are outstanding and unvested as of the covered year-end [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">year-end fair value of equity awards granted in the covered year that are outstanding and unvested as of the covered year-end.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Year-End Fair Value of Equity Awards Granted in the Covered Year that are Outstanding and Unvested as of the Covered Year-End</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ExcessFairValueForEquityAwardModificationsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Excess Fair Value for Equity Award Modifications [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ExcessFairValueForEquityAwardModificationsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Excess fair value for equity award modifications.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_ExcessFairValueForEquityAwardModificationsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Excess Fair Value for Equity Award Modifications</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTStockAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">S C T Stock Awards Column Value [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTStockAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">S C T stock awards column value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_SCTStockAwardsColumnValueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">SCT "Stock Awards" Column Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="apls_NonPeoName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Non Peo Name</link:label>
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          <link:definitionArc xlink:type="arc" order="3" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="4" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="5" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="6" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_TotalAdjustmentsForEquityAwardsMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="7" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_SCTStockAwardsColumnValueMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="8" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_SCTOptionAwardsColumnValueMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="9" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="10" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="11" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="12" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="13" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember" priority="2" use="optional"/>
          <link:definitionArc xlink:type="arc" order="14" xbrldt:closed="false" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllAdjToCompMember" xlink:to="apls_ExcessFairValueForEquityAwardModificationsMember" priority="2" use="optional"/>
        </link:definitionLink>
      </link:linkbase>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="apls_YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" name="YearEndFairValueOfEquityAwardsGrantedInTheCoveredYearThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember" name="AdjustmentForGrantDateValuesInTheSummaryCompensationTableMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember" name="FairValuesAtVestDateForAwardsGrantedAndVestedInCurrentYearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_SCTStockAwardsColumnValueMember" name="SCTStockAwardsColumnValueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember" name="YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatVestedInTheCoveredYearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember" name="VestingDateFairValueOfEquityAwardsGrantedAndVestedInTheCoveredYearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember" name="FairValueAsOfPriorYearEndOfEquityAwardsGrantedInPriorYearsThatFailedToVestInTheCoveredYearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_TotalAdjustmentsForEquityAwardsMember" name="TotalAdjustmentsForEquityAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember" name="YearEndFairValueOfUnvestedAwardsGrantedInTheCurrentYearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_ExcessFairValueForEquityAwardModificationsMember" name="ExcessFairValueForEquityAwardModificationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember" name="ForfeituresDuringCurrentYeareQualToPriorYearEndFairValueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" name="YearOverYearChangeInFairValueOfEquityAwardsGrantedInPriorYearsThatAreOutstandingAndUnvestedAsOfTheCoveredYearEndMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_NonPeoName" name="NonPeoName" type="xbrli:normalizedStringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="apls_SCTOptionAwardsColumnValueMember" name="SCTOptionAwardsColumnValueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember" name="DifferenceInFairValuesBetweenpriorYearEndFairValuesAndVestDateFairValuesForAwardsGrantedInPriorYearsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="apls_YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember" name="YearOverYearDifferenceOfYearEndFairValuesForUnvestedAwardsGrantedInPriorYearsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
