EcoR1 Capital, LLC

In its 13F for Q4 2024 (holdings as of December 31, 2024, filed February 14, 2025), EcoR1 Capital, LLC reported 53 stock positions worth $2.5 billion. Its top holding was Apellis Pharmaceuticals (APLS) at 15.2% of the portfolio, followed by Zymeworks (ZYME, 8.8%) and Crinetics Pharmaceuticals (CRNX, 8.8%). Compared with Q3 2024, it opened 8 new positions, sold out of 15, added to 7 and reduced 9. The biggest buy was a new position in Sarepta Therapeutics (SRPT) and the biggest sale Kura Oncology (KURA, shares −39%).

Most Recent 13F
Q2 2026
Location
San Francisco, CA
CIK
0001587114
Portfolio Value
$2.5B (Q4 2024)
SEC Filing
0000935836-25-000164 ↗ filed Feb 14, 2025

Holdings Value

0$1.0B$2.0B$3.0B$4.0B Q1 2024: $3.9B Q1 2024 Q2 2024: $3.3B Q2 2024 Q3 2024: $2.9B Q3 2024 Q4 2024: $2.5B $2.5B Q4 2024 Q1 2025: $1.7B Q1 2025 Q2 2025: $1.7B Q2 2025 Q3 2025: $2.1B Q3 2025 Q4 2025: $2.2B Q4 2025 Q1 2026: $2.3B Q1 2026 Q2 2026: $2.0B Q2 2026

Holdings 53 stocks · $2.5B
APLS Apellis Pharmaceuticals Inc. 15.18% 11,890,843 $379.4M No change
ZYME Zymeworks Inc. 8.80% 15,028,079 $220.0M Add +11.8%
CRNX Crinetics Pharmaceuticals Inc. 8.77% 4,288,120 $219.3M No change
JAZZ Jazz Pharmaceuticals PLC 8.41% 1,706,469 $210.2M No change
PRTA Prothena Corp. PLC 6.42% 11,584,280 $160.4M No change
XNCR Xencor Inc. 5.65% 6,144,767 $141.2M Add +15.3%
ARVN Arvinas Inc. 5.16% 6,726,491 $128.9M No change
ANAB Anaptysbio Inc. 4.17% 7,873,448 $104.2M Add +1.0%
SRPT Sarepta Therapeutics Inc. 3.75% 770,000 $93.6M New
JANX Janux Therapeutics Inc. 3.15% 1,469,818 $78.7M No change
QURE Uniqure NV 2.40% 3,400,000 $60.0M New
SWTX Springworks Therapeutics Inc. 2.25% 1,560,000 $56.4M New
CRSP Crispr Therapeutics AG 2.19% 1,389,276 $54.7M No change
IMNM Immunome Inc. 1.65% 3,879,415 $41.2M No change
TECX Tectonic Therapeutic Inc. 1.57% 849,143 $39.2M No change
TNGX Tango Therapeutics Inc. 1.31% 10,630,736 $32.8M Reduce -20.3%
THRD Third Harmonic Bio Inc. 1.31% 3,182,444 $32.7M No change
KURA Kura Oncology Inc. 1.24% 3,557,269 $31.0M Reduce -38.7%
NGNE Neurogene Inc. 1.16% 1,271,342 $29.1M No change
ORIC Oric Pharmaceuticals Inc. 1.10% 3,418,068 $27.6M No change
ETON Eton Pharmaceuticals Inc. 0.97% 1,829,603 $24.4M Add +223.2%
MBX MBX Biosciences Inc. 0.93% 1,259,273 $23.2M Add +7.1%
MDGL Madrigal Pharmaceuticals Inc. 0.93% 75,000 $23.1M No change
VYGR Voyager Therapeutics Inc. 0.89% 3,917,546 $22.2M No change
NMRA Neumora Therapeutics Inc. 0.88% 2,071,450 $22.0M No change
CRGX Cargo Therapeutics Inc. 0.85% 1,470,000 $21.2M No change
MLTX Moonlake Immunotherapeutics 0.72% 332,522 $18.0M New
DNA Ginkgo Bioworks Holdings Inc. 0.68% 1,743,344 $17.1M New
RNAM Avidity Biosciences Inc. 0.65% 557,576 $16.2M Reduce -26.4%
MERSANA THERAPEUTICS INC 0.65% 11,328,000 $16.2M Reduce -41.5%
TCRX Tscan Therapeutics Inc. 0.61% 5,000,000 $15.2M No change
ADAPY Adaptimmune Therapeutics-ADR 0.59% 27,404,070 $14.8M No change
KYMR Kymera Therapeutics Inc. 0.56% 350,000 $14.1M New
DYN Dyne Therapeutics Inc. 0.52% 555,644 $13.1M No change
BCYC Bicycle Therapeutics PLC-ADR 0.51% 910,000 $12.7M No change
AVIR Atea Pharmaceuticals Inc. 0.45% 3,341,653 $11.2M Reduce -38.6%
DAWN Day One Biopharmaceuticals I 0.44% 862,068 $10.9M No change
REPL Replimune Group Inc. 0.41% 850,341 $10.3M No change
ALGS Aligos Therapeutics Inc. 0.41% 255,573 $10.2M No change
ATRA Atara Biotherapeutics Inc. 0.28% 532,134 $7.1M Add +13.5%
VERV Verve Therapeutics Inc. 0.28% 1,250,000 $7.0M No change
FATE Fate Therapeutics Inc. 0.20% 3,049,405 $5.0M New
LKFT Lakefront Biotherapeutic-ADR filed as GALAPAGOS NV 0.17% 155,006 $4.3M No change
ALLOVIR INC 0.16% 408,688 $3.9M Reduce -96.4%
KROS Keros Therapeutics Inc. 0.12% 187,500 $3.0M No change
RLAY Relay Therapeutics Inc. 0.11% 641,426 $2.6M Reduce -74.3%
DSGN Design Therapeutics Inc. 0.11% 426,683 $2.6M Add +692.6%
GBIO Generation Bio Co. 0.09% 2,046,867 $2.2M No change
PRME Prime Medicine Inc. 0.08% 700,000 $2.0M No change
WHWK Whitehawk Therapeutics Inc. filed as AADI BIOSCIENCE INC 0.04% 345,253 $1.1M Reduce -81.3%
UPB Upstream Bio Inc. 0.04% 60,000 $986K New
HOOK Hookipa Pharma Inc. 0.03% 388,861 $782K Reduce -32.0%
ARTV Artiva Biotherapeutics Inc. 0.02% 41,453 $418K No change

Options reported separately and not counted above: PFE calls ($132.7M), QURE calls ($6.8M), ETON calls ($2.0M), GLUE calls ($151K).

Other holdings (2): bonds, preferreds, convertibles and warrants · $3.5M (not counted above)
SecurityClassShares / PrincipalValueChange
NUVB.WS Nuvation Bio Inc. -CW27 *W EXP 02/10/202 963,333$2.6MNo change
SRZNW Surrozen Inc.-CW25 *W EXP 08/01/203 66,665$957KNo change

Total filed on the 13F, all lines: $2.5B.

Portfolio Sells Q3 2024 → Q4 2024
KURA Kura Oncology Inc. Reduce -38.7% 1.24% −2.65
TNGX Tango Therapeutics Inc. Reduce -20.3% 1.31% −2.20
CNTA Centessa Pharmaceuticals Ltd. Sold out 0.00% −1.77
VRDN Viridian Therapeutics Inc. Sold out 0.00% −1.53
NUVB Nuvation Bio Inc. Sold out 0.00% −1.51
PCVX Vaxcyte Inc. Sold out 0.00% −1.38
EWTX Edgewise Therapeutics Inc. Sold out 0.00% −1.14
CLDX Celldex Therapeutics Inc. Sold out 0.00% −0.76
IONS Ionis Pharmaceuticals Inc. Sold out 0.00% −0.69
MERSANA THERAPEUTICS INC Reduce -41.5% 0.65% −0.61
PHVS Pharvaris NV Sold out 0.00% −0.57
ITOS Iteos Therapeutics Inc. Sold out 0.00% −0.56
RNAM Avidity Biosciences Inc. Reduce -26.4% 0.65% −0.54
RLAY Relay Therapeutics Inc. Reduce -74.3% 0.11% −0.50
LENZ Lenz Therapeutics Inc. Sold out 0.00% −0.28
AVIR Atea Pharmaceuticals Inc. Reduce -38.6% 0.45% −0.18
ALLOVIR INC Reduce -96.4% 0.16% −0.16
BBIO Bridgebio Pharma Inc. Sold out 0.00% −0.15
PRQR Proqr Therapeutics NV Sold out 0.00% −0.11
WHWK Whitehawk Therapeutics Inc. Reduce -81.3% 0.04% −0.09
KYTX Kyverna Therapeutics Inc. Sold out 0.00% −0.08
HOOK Hookipa Pharma Inc. Reduce -32.0% 0.03% −0.05
MGNX Macrogenics Inc. Sold out 0.00% −0.01
ALLK Allakos LLC Sold out 0.00% −0.00

Portfolio Buys Q3 2024 → Q4 2024
SRPT Sarepta Therapeutics Inc. New 3.75% +3.75
ZYME Zymeworks Inc. Add +11.8% 8.80% +3.02
QURE Uniqure NV New 2.40% +2.40
SWTX Springworks Therapeutics Inc. New 2.25% +2.25
XNCR Xencor Inc. Add +15.3% 5.65% +1.97
ETON Eton Pharmaceuticals Inc. Add +223.2% 0.97% +0.86
MLTX Moonlake Immunotherapeutics New 0.72% +0.72
DNA Ginkgo Bioworks Holdings Inc. New 0.68% +0.68
KYMR Kymera Therapeutics Inc. New 0.56% +0.56
FATE Fate Therapeutics Inc. New 0.20% +0.20
ATRA Atara Biotherapeutics Inc. Add +13.5% 0.28% +0.15
DSGN Design Therapeutics Inc. Add +692.6% 0.11% +0.10
UPB Upstream Bio Inc. New 0.04% +0.04
MBX MBX Biosciences Inc. Add +7.1% 0.93% −0.12
ANAB Anaptysbio Inc. Add +1.0% 4.17% −4.78

Options Activity Q3 2024 → Q4 2024
PFE Pfizer Inc. call New 5,000,000 $132.7M
QURE Uniqure NV call New 385,000 $6.8M
ETON Eton Pharmaceuticals Inc. call Reduce -33.6% 151,400 $2.0M
GLUE Monte Rosa Therapeutics Inc. call New 21,700 $151K

Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.

Notes & Other Activity Q3 2024 → Q4 2024
CMXWQ Caremax-CW *W EXP 06/08/202 Sold out 100,000 $170Kbefore exit

Bonds, preferreds, convertibles and warrants; not part of the stock holdings or percentages above.

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 30$2.0BZYME, ANAB, AKTS, CGON, ETON
Q1 2026 28$2.3BZYME, ANAB, JAZZ, CNTA, CRNX
Q4 2025 26$2.2BZYME, ANAB, JAZZ, CRNX, CNTA
Q3 2025 28$2.1BZYME, ANAB, QURE, JAZZ, CRNX
Q2 2025 34$1.7BZYME, APLS, JAZZ, ANAB, CRNX
Q1 2025 42$1.7BAPLS, JAZZ, ZYME, ANAB, CRNX
Q4 2024 53$2.5BAPLS, ZYME, CRNX, JAZZ, PRTA
Q3 2024 60$2.9BAPLS, ANAB, CRNX, PRTA, JAZZ
Q2 2024 52$3.3BAPLS, PRTA, SRPT, ANAB, CRNX
Q1 2024 54$3.9BAPLS, PRTA, ARVN, SRPT, CRNX