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  <infoTable>
    <nameOfIssuer>ALKERMES PLC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>G01767105</cusip>
    <value>39172000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1400000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1400000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>APELLIS PHARMACEUTICALS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>03753U106</cusip>
    <value>307022217</value>
    <shrsOrPrnAmt>
      <sshPrnamt>12222222</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>12222222</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>APOGEE THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>03770N101</cusip>
    <value>37740000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>500000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>500000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ARGENX SE</nameOfIssuer>
    <titleOfClass>Sponsored ADR</titleOfClass>
    <cusip>04016X101</cusip>
    <value>832540500</value>
    <shrsOrPrnAmt>
      <sshPrnamt>990000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>990000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ARROWHEAD PHARMACEUTICALS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>04280A100</cusip>
    <value>705393750</value>
    <shrsOrPrnAmt>
      <sshPrnamt>10625000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>10625000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ASCENDIS PHARMA</nameOfIssuer>
    <titleOfClass>Sponsored ADR</titleOfClass>
    <cusip>04351P101</cusip>
    <value>1089893310</value>
    <shrsOrPrnAmt>
      <sshPrnamt>5111111</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>5111111</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ASCENDIS PHARMA</nameOfIssuer>
    <titleOfClass>Sponsored ADR</titleOfClass>
    <cusip>04351P101</cusip>
    <value>625000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>50000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <putCall>Call</putCall>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>50000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>AVIDITY BIOSCIENCES INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>05370A108</cusip>
    <value>393469150</value>
    <shrsOrPrnAmt>
      <sshPrnamt>5455000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>5455000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>CELCUITY INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>15102K100</cusip>
    <value>310302211</value>
    <shrsOrPrnAmt>
      <sshPrnamt>3111111</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>3111111</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>CENTESSA PHARMACEUTICALS PLC</nameOfIssuer>
    <titleOfClass>SPONSORED ADS</titleOfClass>
    <cusip>152309100</cusip>
    <value>364034431</value>
    <shrsOrPrnAmt>
      <sshPrnamt>14555555</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>14555555</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>GH RESEARCH PLC</nameOfIssuer>
    <titleOfClass>ORDINARY SHARES</titleOfClass>
    <cusip>G3855L106</cusip>
    <value>22860000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1800000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1800000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>INCYTE CORP</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>45337C102</cusip>
    <value>13333950</value>
    <shrsOrPrnAmt>
      <sshPrnamt>135000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>135000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>KRYSTAL BIOTECH INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>501147102</cusip>
    <value>712226448</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2888888</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2888888</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>KYMERA THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>501575104</cusip>
    <value>581610064</value>
    <shrsOrPrnAmt>
      <sshPrnamt>7474747</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>7474747</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>LEXEO THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>52886X107</cusip>
    <value>32769000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>3300000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>3300000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MADRIGAL PHARMACEUTICALS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>558868105</cusip>
    <value>1052579550</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1807500</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1807500</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MANNKIND CORP</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>56400P706</cusip>
    <value>25199997</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4444444</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>4444444</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>MIND MEDICINE (MINDMED) INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>60255C885</cusip>
    <value>66950000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>5000000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>5000000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>OCULAR THERAPEUTIX INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>67576A100</cusip>
    <value>130842213</value>
    <shrsOrPrnAmt>
      <sshPrnamt>10777777</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>10777777</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>ORUKA THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>687604108</cusip>
    <value>40413535</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1333340</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1333340</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>PTC THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>69366J200</cusip>
    <value>52032600</value>
    <shrsOrPrnAmt>
      <sshPrnamt>685000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>685000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>REVOLUTION MEDICINES INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>76155X100</cusip>
    <value>172840500</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2170000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2170000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>SEPTERNA INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>81734D104</cusip>
    <value>37289500</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1337500</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1337500</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>SOLENO THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>834203309</cusip>
    <value>134270000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2900000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2900000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>SPDR SERIES TRUST - S&amp;P BIOTECH</nameOfIssuer>
    <titleOfClass>ETF</titleOfClass>
    <cusip>78464A870</cusip>
    <value>256053000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2100000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2100000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>STRUCTURE THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>SPONSORED ADS</titleOfClass>
    <cusip>86366E106</cusip>
    <value>455938850</value>
    <shrsOrPrnAmt>
      <sshPrnamt>6555555</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>6555555</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>TAYSHA GENE THERAPIES INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>877619106</cusip>
    <value>119350000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>21700000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>21700000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>TERNS PHARMACEUTICALS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>880881107</cusip>
    <value>175740000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>4350000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>4350000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>UNIQURE NV</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>N90064101</cusip>
    <value>147169500</value>
    <shrsOrPrnAmt>
      <sshPrnamt>6150000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>6150000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>UNITED THERAPEUTICS CORP</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>91307C102</cusip>
    <value>1269802735</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2606060</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2606060</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>VERA THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>92337R101</cusip>
    <value>298213288</value>
    <shrsOrPrnAmt>
      <sshPrnamt>5888888</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>5888888</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>VIRIDIAN THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>92790C104</cusip>
    <value>46680000</value>
    <shrsOrPrnAmt>
      <sshPrnamt>1500000</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>1500000</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>WHITEHAWK THERAPEUTICS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>00032Q104</cusip>
    <value>6895553</value>
    <shrsOrPrnAmt>
      <sshPrnamt>2849402</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>2849402</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
  <infoTable>
    <nameOfIssuer>XENON PHARMACEUTICALS INC</nameOfIssuer>
    <titleOfClass>Common</titleOfClass>
    <cusip>98420N105</cusip>
    <value>243123580</value>
    <shrsOrPrnAmt>
      <sshPrnamt>5424444</sshPrnamt>
      <sshPrnamtType>SH</sshPrnamtType>
    </shrsOrPrnAmt>
    <investmentDiscretion>SOLE</investmentDiscretion>
    <votingAuthority>
      <Sole>5424444</Sole>
      <Shared>0</Shared>
      <None>0</None>
    </votingAuthority>
  </infoTable>
</informationTable>
