Caribou Biosciences halts both allogeneic CAR-T trials as its shares fall 62% in a week
Caribou Biosciences halted trials of both its clinical allogeneic CAR-T programs and will cut staff while it reviews strategic alternatives. CEO Rachel Haurwitz blamed a financing market that made capital impossible to secure.
The Scientist · Science desk
Key figures: Caribou's stock fell 83% over one year; it had 97 employees as of February 27; it cut its workforce by 32% in April 2025; its 2021 IPO raised $321 million in aggregate net proceeds.
| Figure | Value | Note | Claim |
|---|---|---|---|
| Caribou stock decline over one year | 83% | 2 | |
| Staff as of February 27 | 97 employees | 3 | |
| Workforce cut, April 2025 | 32% | 16 | |
| 2021 IPO net proceeds | $321 million | 8 |
What happened
- The halted programs are vispa-cel for relapsed or refractory B-cell non-Hodgkin lymphoma and CB-011, an anti-BCMA therapy for relapsed or refractory multiple myeloma.
- Caribou called the workforce reduction only "substantial"; it had 97 employees as of February 27, according to its 10-K filed March 5.
- Both programs came out of Caribou's move from a platform company serving biopharma partners to a developer of its own genome-edited therapies.
- In April 2025 Caribou had already cut its workforce by 32% and ended all preclinical research and its lupus trial of vispa-cel, before a first patient was dosed.
Why it matters
- contradiction Positive readouts, as GEN describes them, did not buy financing. Either funders found them too thin or the sector is closed whatever the data, and the reporting cannot separate the two.
- constraint A trial stopped for funding yields no efficacy answer. Caribou's clinical test of a PD-1 knockout in an allogeneic CAR-T, a first by its own account, ends with vispa-cel.
- decision Investors and partners sizing allogeneic CAR-T deals now have one company's statement that capital was unobtainable. It comes from the company that failed to raise it, so they must decide how far it generalises.
Haurwitz's post makes two claims, and they need different kinds of evidence. The first is that the science holds up. "This decision is not a loss of belief in our science, our clinical data, or what these programs could mean for patients," Haurwitz, Caribou's co-founder, president and CEO, said in a LinkedIn post [5][7]. GEN reports that the company's turn toward its own therapies "has generated positive data readouts" [15]. The thing this doesn't tell you is what those readouts showed: the report does not include response rates, safety data or Caribou's cash position.
The second claim is about the market. Here the evidence is the company's own failed search for capital and the reaction of its stock, and both fit her account. The shares fell 62% in the week and 83% over the year [1][2]. If the 83% includes the 62%, the shares had already lost about 55% over the earlier part of the year [18].
Both programs stopping together fits a cash decision. It also fits a pipeline with little left in it, since the April 2025 cuts had already closed the preclinical work and the lupus study [16]. The two designs differ. vispa-cel makes three edits with Cas9 chRDNA guides and targets CD19 [11]. CB-011 makes four edits with Cas12a chRDNA guides and targets BCMA [12]. Its B2M edits are there, Caribou said on its website, "to blunt both T and NK cell-mediated rejection of the CAR T-cell therapy by the patient's immune system" [13]. A trial stopped for money does not say whether that works in patients.
We think the record supports a narrow reading: Caribou could not fund these two trials.
The capital markets Caribou entered were different. Its 2021 IPO sold 21.85 million shares at $16, up from an earlier plan of 13.5 million [9]. That is about $350 million gross [17] and $321 million net [8].
What to watch
- What Caribou says the "substantial" workforce cut and the other unspecified cost measures amount to.
- What the strategic review produces, and whether Caribou discloses its cash position alongside it.
- Whether other allogeneic CAR-T developers report the same financing constraint in their own filings.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence55
- Adoption
- Insufficient
- Hype gap−10
- Incentives
- Insufficient
- Confidence55
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
Caribou Biosciences shares plunged 62% over the past week after the company announced plans to evaluate strategic alternatives.
- [2]
The selloff capped a one-year 83% decline in Caribou's stock.
- [3]
Caribou announced an unspecified 'substantial' reduction of its workforce, which numbered 97 people as of February 27 according to its Form 10-K filed March 5, along with other cost reduction measures yet to be specified.
- [4]
Caribou halted trials of vispacabtagene regedleucel (vispa-cel, formerly CB-010) for relapsed or refractory B cell non-Hodgkin lymphoma and of CB-011, an allogeneic anti-BCMA CAR-T therapy for relapsed or refractory multiple myeloma; both are allogeneic CAR T-cell programs and the company's only two clinical-phase candidates.
- [5]
"This decision is not a loss of belief in our science, our clinical data, or what these programs could mean for patients."
- [6]
Haurwitz said the current financing environment for allogeneic CAR T-cell therapies has made it impossible to secure the capital required to responsibly advance them.
- [7]
Rachel Haurwitz is Caribou's co-founder, president and CEO and announced the strategic review in a post on LinkedIn.
- [8]
Caribou's 2021 initial public offering raised $321 million in aggregate net proceeds after underwriting discounts and commissions and other offering expenses.
- [9]
In its 2021 IPO Caribou sold 21.85 million shares at $16 a share, up from earlier plans to sell 13.5 million shares.
- [10]
Caribou has said vispa-cel is the first allogeneic CAR T-cell therapy 'to our knowledge' to reach the clinic with a PD-1 knockout, a strategy designed to limit premature CAR T-cell exhaustion.
- [11]
To manufacture vispa-cel, Caribou uses Cas9 hybrid RNA-DNA guides (chRDNA) to make three edits: a TRAC knockout to remove the T cell receptor, insertion of an anti-CD19 CAR into the TRAC gene, and a PD-1 knockout.
- [12]
To manufacture CB-011, Caribou uses Cas12a chRDNAs to make four edits: a TRAC knockout, insertion of a humanized anti-BCMA CAR into TRAC, insertion of a B2M-HLA-E-peptide fusion gene into the B2M gene, and the resulting knockout of endogenous B2M.
- [13]
Caribou explained on its website that the CB-011 method eliminates endogenous HLA class I presentation on the CAR T cells and expresses HLA-E "to blunt both T and NK cell-mediated rejection of the CAR T-cell therapy by the patient's immune system".
- [14]
CB-011 and vispa-cel followed a strategic pivot by Caribou from a platform company for biopharma partners applying genome editing in research or product development to a developer of genome-edited therapies based on its own CRISPR technology.
- [15]
GEN reports that the pivot 'has generated positive data readouts' but has not shielded Caribou from the financial challenges faced by numerous gene-edited therapy developers.
- [16]
In April 2025 Caribou cut its workforce by 32% and pruned its pipeline by ending all preclinical research and the Phase I GALLOP trial of vispa-cel in lupus, before the first patient could be dosed.
- [17]
The IPO's gross proceeds were about $349.6 million, assuming all 21.85 million shares sold at $16.
- [18]
If the one-year 83% decline includes the 62% weekly drop, shares had fallen about 55% before the week: 1 - (0.17 / 0.38) = 0.553.
Sources
1 independent publisher whose own reporting we read for this story.
- genengnews.comStockWatch: Caribou Plunges as It Pursues Strategic Alternatives
1 article · October 12, 2026
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