Octagon Capital Advisors LP In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Octagon Capital Advisors LP reported 25 stock positions worth $640.2 million . Its top holding was Abivax SA-ADR (ABVX) at 17.6% of the portfolio, followed by Dianthus Therapeutics (DNTH, 14.9% ) and Gossamer Bio (GOSS, 7.0% ). Compared with Q2 2025, it opened 4 new positions, sold out of 8, added to 7 and reduced 7. The biggest buy was Abivax SA-ADR (ABVX, shares +5% ) and the biggest sale an exit from Verona Pharma (VRNA).
Location NEW YORK, NY
CIK 0001839435
Portfolio Value $640.2M (Q3 2025) Holdings 25 stocks · $640.2M Holdings quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock % Of Portfolio ▼ Shares Held Total Value Change vs Q2 2025 ABVX Abivax SA-ADR 1,325,000 $112.5M Add +4.6% DNTH Dianthus Therapeutics Inc. 2,416,667 $95.1M Add +3.2% GOSS Gossamer Bio Inc. 17,050,000 $44.8M Reduce -7.1% COGT Cogent Biosciences Inc. 2,874,111 $41.3M Add +4.0% AVBP Arrivent Biopharma Inc. 1,971,054 $36.4M Add +1.3% OCUL Ocular Therapeutix Inc. 2,624,000 $30.7M Add +8.2% TSHA Taysha Gene Therapies Inc. 9,067,500 $29.7M Reduce -28.0% MRUS Merus NV 308,000 $29.0M Reduce -20.8% TRVI Trevi Therapeutics Inc. 2,815,000 $25.8M Reduce -23.3% MIND MEDICINE MINDMED INC 2,130,000 $25.1M No change APLS Apellis Pharmaceuticals Inc. 903,500 $20.4M No change KYMR Kymera Therapeutics Inc. 360,000 $20.4M Add +35.3% CNTA Centessa Pharmaceuticals Ltd. 830,000 $20.1M Reduce -19.4% PHVS Pharvaris NV 722,595 $18.0M Add +7.4% KALV Kalvista Pharmaceuticals Inc. 1,273,333 $15.5M No change CRBP Corbus Pharmaceuticals Holdi 1,115,000 $14.1M No change BBOT Bridgebio Oncology Therapeut 1,043,110 $12.1M New DBVT DBV Technologies SA-Spon ADR 1,018,021 $10.2M No change NUVB Nuvation Bio Inc. 2,633,334 $9.7M Reduce -65.8% CDTX Cidara Therapeutics Inc. 100,000 $9.6M New MAZE Maze Therapeutics Inc. 177,667 $4.6M No change NGNE Neurogene Inc. 252,000 $4.4M Reduce -16.8% UNCY Unicycive Therapeutics Inc. 1,000,000 $4.4M No change PEPG Pepgen Inc. 700,000 $3.2M New GPCR Structure Therapeutics Inc. 115,000 $3.2M New
Options reported separately and not counted above: CDTX calls ($19.2M).
Other holdings (1): bonds, preferreds, convertibles and warrants · $385K (not counted above) Security Class Shares / Principal Value Change NUVB.WS Nuvation Bio Inc. -CW27 *W EXP 02/10/202 104,112 $385K Reduce -32.4%
Total filed on the 13F, all lines: $640.6M.
Portfolio Sells Q2 2025 → Q3 2025 Portfolio Sells quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock Change vs Q2 2025 % Of Portfolio Change To Portfolio ▲ VRNA Verona Pharma Ltd. Sold out 0.00% −7.00 SPRY Ars Pharmaceuticals Inc. Sold out 0.00% −5.17 ATYR Atyr Pharma Inc. Sold out 0.00% −4.25 TRML Tourmaline Bio Inc. Sold out 0.00% −3.18 NUVB Nuvation Bio Inc. Reduce -65.8% 1.52% −1.77 TSHA Taysha Gene Therapies Inc. Reduce -28.0% 4.63% −1.76 MLTX Moonlake Immunotherapeutics Sold out 0.00% −1.53 BBOT Bridgebio Oncology Therapeut Sold out 0.00% −0.58 TRVI Trevi Therapeutics Inc. Reduce -23.3% 4.02% −0.39 NGNE Neurogene Inc. Reduce -16.8% 0.68% −0.31 KLRS Kalaris Therapeutics Inc. Sold out 0.00% −0.21 ERAS Erasca Inc. Sold out 0.00% −0.20 MRUS Merus NV Reduce -20.8% 4.53% +0.04 CNTA Centessa Pharmaceuticals Ltd. Reduce -19.4% 3.14% +0.17 GOSS Gossamer Bio Inc. Reduce -7.1% 7.00% +2.05
Portfolio Buys Q2 2025 → Q3 2025 Portfolio Buys quarter Q2 2026 Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024 Q1 2024
Stock Change vs Q2 2025 % Of Portfolio Change To Portfolio ▼ ABVX Abivax SA-ADR Add +4.6% 17.57% +15.44 DNTH Dianthus Therapeutics Inc. Add +3.2% 14.85% +5.27 COGT Cogent Biosciences Inc. Add +4.0% 6.45% +2.09 BBOT Bridgebio Oncology Therapeut New 1.89% +1.89 CDTX Cidara Therapeutics Inc. New 1.50% +1.50 KYMR Kymera Therapeutics Inc. Add +35.3% 3.18% +0.63 PEPG Pepgen Inc. New 0.51% +0.51 GPCR Structure Therapeutics Inc. New 0.50% +0.50 PHVS Pharvaris NV Add +7.4% 2.82% +0.22 OCUL Ocular Therapeutix Inc. Add +8.2% 4.79% −0.15 AVBP Arrivent Biopharma Inc. Add +1.3% 5.68% −3.62
Options Activity Q2 2025 → Q3 2025 Security Type Change vs Q2 2025 Underlying Shares Value ▼ CDTX Cidara Therapeutics Inc. call New 200,000 $19.2M
Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.
Notes & Other Activity Q2 2025 → Q3 2025 Security Class Change vs Q2 2025 Shares / Principal Value ▼ NUVB.WS Nuvation Bio Inc. -CW27 *W EXP 02/10/202 Reduce -32.4% 104,112 $385K
Bonds, preferreds, convertibles and warrants; not part of the stock holdings or percentages above.
All Filings Quarter Positions 13F Reported Value Top Holdings Q2 2026 26 $1.1B DNTH, DFTX, ABVX, COGT, ALMS Q1 2026 29 $903.6M DNTH, COGT, ABVX, ALMS, DFTX Q4 2025 26 $798.8M ABVX, DNTH, COGT, TSHA, GOSS Q3 2025 25 $640.2M ABVX, DNTH, GOSS, COGT, AVBP Q2 2025 29 $455.3M DNTH, AVBP, VRNA, TSHA, SPRY Q1 2025 Amended 33 $460.1M APLS, DNTH, AVBP, TRVI, CNTA Q4 2024 30 $587.1M APLS, AVBP, DNTH, CNTA, VRNA Q3 2024 40 $623.9M APLS, VRNA, GPCR, DNTH, AVBP Q2 2024 44 $606.1M APLS, DNTH, GPCR, INSM, DYN Q1 2024 56 $822.6M APLS, ALPN, DNTH, VRNA, DYN