<?xml version="1.0" encoding="us-ascii"?>
<!-- RRD ActiveDisclosure(SM) XBRL Schema Document - http://www.financial.rrd.com/ -->
<!-- Creation Date      : 2014-08-07T02:46:05.9621875+00:00 -->
<!-- Version            : 1.9.0.3 -->
<!-- Package ID         : 77562E001D5B3F84277C8DC850E5A3FE-0001401667-001406 -->
<!-- Copyright (c) 2014 R. R. Donnelley & Sons Company. All Rights Reserved. -->
<schema xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:us-types="http://fasb.org/us-types/2013-01-31" xmlns:stpr="http://xbrl.sec.gov/stpr/2011-01-31" xmlns:sic="http://xbrl.sec.gov/sic/2011-01-31" xmlns:invest="http://xbrl.sec.gov/invest/2013-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:pbyi="http://www.pumabiotechnology.com/20140630" xmlns:us-gaap="http://fasb.org/us-gaap/2013-01-31" xmlns:dei="http://xbrl.sec.gov/dei/2013-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:country="http://xbrl.sec.gov/country/2013-01-31" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:currency="http://xbrl.sec.gov/currency/2012-01-31" xmlns:naics="http://xbrl.sec.gov/naics/2011-01-31" xmlns:exch="http://xbrl.sec.gov/exch/2013-01-31" xmlns:num="http://www.xbrl.org/dtr/type/numeric" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.pumabiotechnology.com/20140630" xmlns="http://www.w3.org/2001/XMLSchema">
  <import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance" />
  <import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase" />
  <import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt" />
  <import schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/numeric" />
  <import schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/non-numeric" />
  <import schemaLocation="http://xbrl.fasb.org/us-gaap/2013/elts/us-types-2013-01-31.xsd" namespace="http://fasb.org/us-types/2013-01-31" />
  <import schemaLocation="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd" namespace="http://fasb.org/us-gaap/2013-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/dei/2013/dei-2013-01-31.xsd" namespace="http://xbrl.sec.gov/dei/2013-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd" namespace="http://xbrl.sec.gov/invest/2013-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd" namespace="http://xbrl.sec.gov/country/2013-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/currency/2012/currency-2012-01-31.xsd" namespace="http://xbrl.sec.gov/currency/2012-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/exch/2013/exch-2013-01-31.xsd" namespace="http://xbrl.sec.gov/exch/2013-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/naics/2011/naics-2011-01-31.xsd" namespace="http://xbrl.sec.gov/naics/2011-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" namespace="http://xbrl.sec.gov/sic/2011-01-31" />
  <import schemaLocation="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd" namespace="http://xbrl.sec.gov/stpr/2011-01-31" />
  <annotation>
    <appinfo>
      <link:roleType id="TemplateLink" roleURI="http://www.pumabiotechnology.com/20140630/role/TemplateLink" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>00000 - Document - Template Link</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pbyi-20140630_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:title="Calculation Links, all" xlink:type="simple" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pbyi-20140630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pbyi-20140630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Label Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pbyi-20140630_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedBalanceSheets" id="Role_StatementCondensedConsolidatedBalanceSheets">
        <link:definition>100010 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedBalanceSheetsParenthetical" id="Role_StatementCondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>100020 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedStatementsOfOperations" id="Role_StatementCondensedConsolidatedStatementsOfOperations">
        <link:definition>100030 - Statement - Condensed Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedStatementsOfComprehensiveLoss" id="Role_StatementCondensedConsolidatedStatementsOfComprehensiveLoss">
        <link:definition>100040 - Statement - Condensed Consolidated Statements of Comprehensive Loss</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedStatementsOfStockholdersEquity" id="Role_StatementCondensedConsolidatedStatementsOfStockholdersEquity">
        <link:definition>100050 - Statement - Condensed Consolidated Statements of Stockholders&apos; Equity</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedStatementsOfStockholdersEquityParenthetical" id="Role_StatementCondensedConsolidatedStatementsOfStockholdersEquityParenthetical">
        <link:definition>100060 - Statement - Condensed Consolidated Statements of Stockholders&apos; Equity (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/StatementCondensedConsolidatedStatementsOfCashFlows" id="Role_StatementCondensedConsolidatedStatementsOfCashFlows">
        <link:definition>100070 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureBusinessAndBasisOfPresentation" id="Role_DisclosureBusinessAndBasisOfPresentation">
        <link:definition>100080 - Disclosure - Business and Basis of Presentation</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSignificantAccountingPolicies" id="Role_DisclosureSignificantAccountingPolicies">
        <link:definition>100090 - Disclosure - Significant Accounting Policies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePrepaidExpensesAndOther" id="Role_DisclosurePrepaidExpensesAndOther">
        <link:definition>100100 - Disclosure - Prepaid Expenses and Other</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePropertyAndEquipment" id="Role_DisclosurePropertyAndEquipment">
        <link:definition>100110 - Disclosure - Property and Equipment</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureAccruedExpenses" id="Role_DisclosureAccruedExpenses">
        <link:definition>100120 - Disclosure - Accrued Expenses</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureStockholdersEquity" id="Role_DisclosureStockholdersEquity">
        <link:definition>100130 - Disclosure - Stockholders&apos; Equity</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSubsequentEvents" id="Role_DisclosureSubsequentEvents">
        <link:definition>100140 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSignificantAccountingPoliciesPolicies" id="Role_DisclosureSignificantAccountingPoliciesPolicies">
        <link:definition>100150 - Disclosure - Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSignificantAccountingPoliciesTables" id="Role_DisclosureSignificantAccountingPoliciesTables">
        <link:definition>100160 - Disclosure - Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePrepaidExpensesAndOtherTables" id="Role_DisclosurePrepaidExpensesAndOtherTables">
        <link:definition>100170 - Disclosure - Prepaid Expenses and Other (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePropertyAndEquipmentTables" id="Role_DisclosurePropertyAndEquipmentTables">
        <link:definition>100180 - Disclosure - Property and Equipment (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureAccruedExpensesTables" id="Role_DisclosureAccruedExpensesTables">
        <link:definition>100190 - Disclosure - Accrued Expenses (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureStockholdersEquityTables" id="Role_DisclosureStockholdersEquityTables">
        <link:definition>100200 - Disclosure - Stockholders&apos; Equity (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureBusinessAndBasisOfPresentationAdditionalInformationDetail" id="Role_DisclosureBusinessAndBasisOfPresentationAdditionalInformationDetail">
        <link:definition>100210 - Disclosure - Business and Basis of Presentation - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSignificantAccountingPoliciesAdditionalInformationDetail" id="Role_DisclosureSignificantAccountingPoliciesAdditionalInformationDetail">
        <link:definition>100220 - Disclosure - Significant Accounting Policies - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureAssetsMeasuredAtFairValueOnRecurringBasisDetail" id="Role_DisclosureAssetsMeasuredAtFairValueOnRecurringBasisDetail">
        <link:definition>100230 - Disclosure - Assets Measured at Fair Value on Recurring Basis (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureComponentsOfPrepaidExpensesAndOtherDetail" id="Role_DisclosureComponentsOfPrepaidExpensesAndOtherDetail">
        <link:definition>100240 - Disclosure - Components of Prepaid Expenses and Other (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePropertyAndEquipmentDetail" id="Role_DisclosurePropertyAndEquipmentDetail">
        <link:definition>100250 - Disclosure - Property and Equipment (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureAccruedExpensesDetail" id="Role_DisclosureAccruedExpensesDetail">
        <link:definition>100260 - Disclosure - Accrued Expenses (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetail" id="Role_DisclosureStockholdersEquityAdditionalInformationDetail">
        <link:definition>100270 - Disclosure - Stockholders Equity - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureStockBasedCompensationExpenseDetail" id="Role_DisclosureStockBasedCompensationExpenseDetail">
        <link:definition>100280 - Disclosure - Stock-Based Compensation Expense (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureFairValueOptionsWeightedAverageAssumptionsDetail" id="Role_DisclosureFairValueOptionsWeightedAverageAssumptionsDetail">
        <link:definition>100290 - Disclosure - Fair Value Options Weighted-Average Assumptions (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureActivityWithRespectToOptionsGrantedDetail" id="Role_DisclosureActivityWithRespectToOptionsGrantedDetail">
        <link:definition>100300 - Disclosure - Activity with Respect to Options Granted (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureStockOptionsDetail" id="Role_DisclosureStockOptionsDetail">
        <link:definition>100310 - Disclosure - Stock Options (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosurePerformanceSharesDetail" id="Role_DisclosurePerformanceSharesDetail">
        <link:definition>100320 - Disclosure - Performance Shares (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.pumabiotechnology.com/20140630/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetail" id="Role_DisclosureSubsequentEventsAdditionalInformationDetail">
        <link:definition>100330 - Disclosure - Subsequent Events - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </appinfo>
  </annotation>
  <element id="pbyi_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_IssuanceOfCommonStockInExchangeForConvertibleNotesShares" name="IssuanceOfCommonStockInExchangeForConvertibleNotesShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_IssuanceOfCommonStockInExchangeForConvertibleNotesValue" name="IssuanceOfCommonStockInExchangeForConvertibleNotesValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <element id="pbyi_PublicOfferingMember" name="PublicOfferingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_PrepaidExpenseAndOtherAssetsTextBlock" name="PrepaidExpenseAndOtherAssetsTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_ReimbursableExpensesPolicyTextBlock" name="ReimbursableExpensesPolicyTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_PrepaidExpenseAndOtherAssetsTableTextBlock" name="PrepaidExpenseAndOtherAssetsTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems" name="OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTable" name="OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_NoncashOrPartNoncashAcquisitionNoncashFinancialOrEquityInstrumentSharesReceived" name="NoncashOrPartNoncashAcquisitionNoncashFinancialOrEquityInstrumentSharesReceived" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_MergerStockConversionRatio" name="MergerStockConversionRatio" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <element id="pbyi_CashEquivalentsOriginalMaturity" name="CashEquivalentsOriginalMaturity" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_SignificantAccountingPoliciesLineItems" name="SignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_SignificantAccountingPoliciesTable" name="SignificantAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_LicenseAgreementNumberOfDaysToReviewInvoiceAndSupportingDocumentation" name="LicenseAgreementNumberOfDaysToReviewInvoiceAndSupportingDocumentation" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_ReductionInExcessCapCosts" name="ReductionInExcessCapCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <element id="pbyi_PrepaidExpensesLineItems" name="PrepaidExpensesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_PrepaidExpensesAndOtherAssetsTable" name="PrepaidExpensesAndOtherAssetsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ClinicalResearchMember" name="ClinicalResearchMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ClinicalMember" name="ClinicalMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_InsuranceMember" name="InsuranceMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_AccruedDevelopmentCosts" name="AccruedDevelopmentCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <element id="pbyi_AccruedClinicalExpensesCurrent" name="AccruedClinicalExpensesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <element id="pbyi_ScheduleOfAccruedLiabilitiesLineItems" name="ScheduleOfAccruedLiabilitiesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ScheduleOfAccruedLiabilitiesTable" name="ScheduleOfAccruedLiabilitiesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_StockholdersEquityNoteLineItems" name="StockholdersEquityNoteLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_StockholdersEquityNoteTable" name="StockholdersEquityNoteTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_UnderwrittenPublicOfferingMember" name="UnderwrittenPublicOfferingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_OverallotmentOptionExerciseByUnderwritersMember" name="OverallotmentOptionExerciseByUnderwritersMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsInitialContractualTerm" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsInitialContractualTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_EquityIncentivePlanTwentyElevenMember" name="EquityIncentivePlanTwentyElevenMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_EquityIncentiveAmendmentPlanTwentyElevenMember" name="EquityIncentiveAmendmentPlanTwentyElevenMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ShareBasedCompensationEffectOnEarningsPerShareBasicAndDiluted" name="ShareBasedCompensationEffectOnEarningsPerShareBasicAndDiluted" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_ShareBasedCompensationLineItems" name="ShareBasedCompensationLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ShareBasedCompensationTable" name="ShareBasedCompensationTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ResearchAndDevelopmentMember" name="ResearchAndDevelopmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_GeneralAndAdministrativeMember" name="GeneralAndAdministrativeMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_EmployeeMember" name="EmployeeMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm3" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm3" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageRemainingContractualTerm" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageRemainingContractualTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedIntrinsicValue" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedIntrinsicValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <element id="pbyi_NonVestedStockOptionsMember" name="NonVestedStockOptionsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExercisableExercisedInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExercisableExercisedInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsWeightedAverageGrantDateFairValueAbstract" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsWeightedAverageGrantDateFairValueAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <element id="pbyi_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionVestedAndExercisedInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionVestedAndExercisedInPeriodWeightedAverageGrantDateFairValue" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <element id="pbyi_PercentageOfIncrementalAnnualRoyalties" name="PercentageOfIncrementalAnnualRoyalties" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
</schema>


