Large-cap healthcare outperformed this week: XLV gained 1.4% through Tuesday, while XBI fell 1.4% and IBB declined 0.5%.
- Biotech still leads year-to-date, with XBI up 26% and IBB up 20%, ahead of SPY’s 12% gain.
- Vera said its kidney drug Trutakna substantially slowed kidney-function decline in the Phase 3 Origin 3 study.
- Ultragenyx is awaiting a Sept.19 FDA decision on UX111, its gene therapy for Sanfilippo syndrome type A.
Biotech’s 2026 rally cooled this week even as drug developers delivered major clinical updates. Definium Therapeutics (DFTX), Vera Therapeutics (VERA) and GSK (GSK) led the early news cycle, while Ultragenyx Pharmaceutical (RARE) faces the week’s key remaining FDA decision.
Big Pharma Beats Biotech Sector
Large-cap healthcare emerged as the relative winner through Tuesday. The Health Care Select Sector SPDR Fund (XLV) gained 1.4% for the week, while the SPDR S&P Biotech ETF (XBI) fell 1.4%. The iShares Biotechnology ETF (IBB) slipped 0.5%, compared with declines of 0.9% for the SPDR S&P 500 ETF Trust (SPY) and 1.4% for the Invesco QQQ Trust (QQQ).
On Tuesday, XBI dropped 2.3% to $154.03, and IBB fell 1.3% to $202. XLV was nearly flat at $167.67, while SPY and QQQ declined 0.5% and 0.7%, respectively. However, the year-to-date picture still favors biotech: XBI has gained 26% and IBB 20%, compared with 15% for QQQ, 12% for SPY, and 9% for XLV.
Key Biotech Developments So Far This Week
| Day | Ticker | Development | Key Details |
| Monday | DFTX | Phase 3 anxiety win | A single 100-microgram dose of DT120 reduced anxiety scores by 9.8 points at week 12, versus 4.7 for placebo. Definium plans a pre-NDA meeting in the fourth quarter and a filing in the first half of 2027. |
| Monday | GSK | First-line Jideytro data | In 94 evaluable, previously untreated ROS1-positive lung cancer patients, GSK reported a 94% response rate and 90% progression-free survival at 12 months. |
| Monday | GSK | Small-cell lung cancer results | Median overall survival reached 18.5 months with Risvutatug Rezetecan, versus 10.3 months with Topotecan in a China-based Phase 3 trial. |
| Monday-Tuesday | IBRX | WCLC and H.C. Wainwright participation | ImmunityBio was on the conference circuit as investors tracked the commercial rollout of Anktiva. |
| Tuesday | VERA | Confirmatory ORIGIN 3 results | Mean kidney-function decline at week 52 was 0.1 with Trutakna versus 5.7 with placebo. Vera plans a fourth-quarter filing for traditional approval. |
| Tuesday | GSK | Chimagen oncology deal | GSK agreed to acquire a trispecific multiple-myeloma drug in a deal worth up to $750 million. |
| Tuesday | SMMT | Ivonescimab at WCLC | Summit and Akeso presented findings from the Harmoni-2 and global Harmoni lung-cancer programs. |
| Tuesday | BNTX, BMY | Pumitamig at WCLC | The companies presented data involving their PD-L1/VEGF bispecific antibody. |
| Tuesday | LEGN | New CEO | Legend appointed former Novartis executive Ingrid Zhang as CEO |
What This Week’s Clinical Results Mean
Definium Therapeutics’ (DFTX) DT120 is a fast-dissolving formulation of Lysergide, the pharmaceutical form of LSD. Panorama marked its second successful Phase 3 anxiety trial and third positive late-stage study overall, including one in major depressive disorder.
GSK’s (GSK) Jideytro is already approved for previously treated ROS1-positive lung cancer after receiving an early FDA nod in July. Its next U.S. catalyst is a filing for first-line use this year. GSK is also running a global Phase 3 study of Risvutatug Rezetecan, an antibody-drug conjugate that carries a cancer-killing payload directly to targeted cells.
The WCLC presentations also highlighted rising competition among PD-(L)1/VEGF bispecific antibodies. Summit Therapeutics’ (SMMT) Ivonescimab and BioNTech (BNTX)-Bristol Myers Squibb’s (BMY) Pumitamig combine immune-checkpoint inhibition with blocking the blood supply tumors need to grow.
Vera Therapeutics’ (VERA) Origin 3 study measured eGFR, a key indicator of kidney function. Trutakna received accelerated approval in July based on reducing protein in the urine. Meanwhile, ImmunityBio’s (IBRX) main commercial focus is Anktiva, an IL-15-based immune activator approved with BCG for certain patients with bladder cancer.
New FDA Approvals Put Drug Launches In Focus
Scholar Rock Holding (SRRK) entered the week with its first commercial product after the FDA approved Isembyld for spinal muscular atrophy patients already receiving an SMN2-directed therapy. The drug targets myostatin, a protein that restricts muscle growth, making it the first approved muscle-targeted SMA treatment.
Telix Pharmaceuticals (TLX) received approval for Pixclara, a radioactive PET imaging agent designed to distinguish recurrent or progressing glioma from treatment-related changes. AstraZeneca (AZN), meanwhile, said the Phase 3 Serena-4 study of Camizestrant with Pfizer’s Ibrance failed to delay disease progression in first-line advanced breast cancer.
The Week’s Remaining Healthcare Catalysts
| Date | Ticker/Event | What To Watch |
| Wednesday, Sept. 16 | GPCR, CMPS, ARWR, JSPR, IBRX | Final Morgan Stanley and H.C. Wainwright sessions |
| Wednesday, Sept.16 | FDA PDUFA meeting | Discussion of future drug-review commitments, staffing, sponsor meetings, and manufacturing assessments. |
| Thursday, Sept.17 | CMPS at Deutsche Bank Healthcare Summit | Commentary on COMP360. |
| Thursday, Sept.17 | Fierce Pharma Week and Neuropsychiatric Drug Development Summit | Final sessions covering commercialization, medical affairs, and neuroscience drug development. |
| Friday, Sept.18 | GSK | No Jideytro decision is pending. |
| Saturday, Sept.19 | RARE - UX111 | FDA decision on Ultragenyx’s gene therapy for Sanfilippo syndrome type A. |
The FDA’s Wednesday meeting concerns the next reauthorization of the Prescription Drug User Fee Act, under which drugmakers pay fees that help fund regulatory reviews.
Meanwhile, Ultragenyx’s UX111 is an AAV9 gene therapy for Sanfilippo syndrome type A, an inherited disease that causes progressive and irreversible neurological decline. The firm is seeking accelerated approval and said UX111 would become the first approved treatment for the disease. The FDA’s earlier complete response letter raised concerns about manufacturing and facility-inspection matters. Since the deadline falls on Saturday, the decision could be disclosed on Friday or during the weekend.
What Biotech Investors Should Watch Next Week
Merck (MRK) said Monday, Sept.21 is the FDA deadline for an application seeking an updated U.S. label for Winrevair. Winrevair is approved for pulmonary arterial hypertension, a progressive disease involving elevated pressure in the arteries between the heart and lungs.
Additionally, Sellas Life Sciences (SLS) will present three preclinical studies of SLS009, or Tambiciclib, at the AACR Conference on Pancreatic Cancer from Sept.25 through Sept. 28. SLS009 blocks CDK9, a protein involved in activating genes cancer cells use to grow and survive. Separately, Sellas is continuing its Phase 3 Regal study of Galinpepimut-S (GPS) in acute myeloid leukemia (AML). Its final analysis will be triggered after the prespecified 80th death, and Sellas had recorded 78 events as of May.
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