in vivo CAR-T programs – Ph 1 data at EHA?

Research evidence excerpt

in vivo CAR-T programs – Ph 1 data at EHA?

Flash Note Health Care | Biotechnology/Small Cap

May 12, 2026

Legend Biotech Corp. Umer Raffat Jonathan Miller 212-888-3905 212 446 5614

LEGN | $25.58 umer.raffat@evercoreisi.com jonathan.miller@evercoreisi.com

Outperform | Target Price/Base Case: N/A

Commentary

There’s been a strong investor interest in figuring out what Legend’s in vivo CAR-T programs are and what

data is coming

But before we go too far, some of the questions are far more basic … e.g., what is the name of the program

etc.

Let’s go through step by step:

Vector:

Legend is using lentivirus (not LNP).

In theory, this lends itself to cancer setting - and not optimal for immunology setting (in case re-dosing

needed)

First in vivo update: CD19/CD20 … data likely at EHA

The program is called TAVEC-100. On call just now, mgmt. mentioned LB2501 – but that’s an internal name

TAVEC-100 has a n=30 trial ongoing in China

We will get early data from this

What am I looking for in the first in vivo data update in lymphoma for CD19/CD20?

Transduction:

- First: if you dose 10 pts, do all 10 develop CAR-T?

- Transduction and cell growth are critical considerations for in vivo CAR-Ts

- I’ve spoken to some pharma R&D heads who mention in vivo CAR-T datasets where some animals

don’t develop CAR-T/suboptimal cell expansion

- BTW, Legend wants to focus on transduction efficiency (not just transduction units)

Immunogenicity:

- few days post dosing – any gr 3 CRS or neurotox?

Early efficacy signals:

- Starting dose matters

- I believe Legend is using 10^6 as starting dose DL1 – which is lower than what Kelonia used in BCMA

in vivo at DL1 (and they later went to DL-1 at e^6).

- Based on body language on call, they likely have an early efficacy signal … but we don’t know how