$80 Million Arcellx Sale Follows Steep Stock Drop as Rival Drug Emerges

Perceptive Advisors disclosed a sale of 1,002,282 Arcellx (ACLX 3.64%) shares in a February 17, 2026, SEC filing, with the estimated transaction value at $79.96 million based on quarterly average pricing.

What happened

According to a SEC filing dated February 17, 2026, Perceptive Advisors reduced its Arcellx holdings by 1,002,282 shares during the fourth quarter. The estimated value of these share sales is $79.96 million, based on the mean unadjusted closing price for the quarter. The quarter-end value of the Arcellx position declined by $107.06 million, a figure that includes both share reduction and share price movements.

What else to know

• Top holdings after the filing:
  • NASDAQ:PRAX: $588.30 million (10.8% of AUM)
  • NASDAQ:CELC: $315.20 million (5.8% of AUM)
  • NASDAQ:RYTM: $272.57 million (5.0% of AUM)
  • NASDAQ:ASND: $230.60 million (4.2% of AUM)
  • NASDAQ:APGE: $175.92 million (3.2% of AUM)
• As of February 17, 2026, Arcellx shares were priced at $70.20, up 9.2% over the past year and underperforming the S&P 500 by 4.3 percentage points.

Company overview

Company snapshot

• Arcellx develops immunotherapies, with a primary focus on CART-ddBCMA for relapsed or refractory multiple myeloma, and additional pipeline candidates targeting acute myeloid leukemia, myelodysplastic syndrome, and solid tumors.
• Arcellx operates as a clinical-stage biotechnology company.

Arcellx is a clinical-stage biotechnology company leveraging proprietary cell therapy platforms to address unmet medical needs in oncology. With a specialized pipeline targeting multiple myeloma and hematologic malignancies, the company positions itself at the forefront of next-generation immunotherapies. Its strategic focus on innovative product candidates and collaborative partnerships underpins its competitive advantage in the biotechnology sector.

What this transaction means for investors

This move comes as Arcellx is no longer just competing against other approved CAR-Ts. It is defending its future against a new delivery model.

In November, Kelonia’s three-patient data set was enough to send Arcellx down roughly 17% in a single session. The in vivo CAR-T approach could theoretically eliminate apheresis, ex vivo manufacturing, and lymphodepletion. That is disruptive language in a space built on complex logistics. But the follow-up was just three months, and the best reported response was a very good partial response. Though shares have yet to recover, analysts at Guggenheim and Citi both argued the sell-off was overdone.

Arcellx’s anito-cel is already in Phase 3 for relapsed or refractory multiple myeloma in partnership with Gilead’s Kite unit, putting it in a far more advanced position than early proof-of-concept data. Shares are up about 9% over the past year but have fallen sharply since November, underscoring how sentiment can flip quickly in biotech.

For long-term investors, this is about probability and positioning. Advanced clinical assets with established partners tend to carry different risk profiles than platform concepts in three patients. Volatility is part of the model. The question is whether anito-cel’s durability can hold its ground as the science evolves.