Okay, what’s going on with target alpha therapies right now?
Lilly paid $1.4 billion for RayzeBio’s actinium radioligand program in 2024.
Bicycle Therapeutics locked up 15 years of uranium supply to make its own Pb-212.
Perspective, AdvanCell, RadioMedix and TAG1 are all working on different pieces of the supply chain.
Seems like everyone wants alpha-emitting radioligands because the physics is just better than beta emitters for killing cancer cells without hitting neighbors.
At AACR this weekend, AlphaGen Therapeutics, a Shanghai-based player, presented preclinical data on two Pb-212 programs.
One of them already has human imaging data.
The lead asset, AG1206, is a macrocyclic peptide radioligand targeting fibroblast activation protein (FAP). Reported picomolar binding affinity. Favorable tumor-to-kidney ratios in preclinical models. And, crucially, early clinical imaging validation with strong tumor uptake and minimal background signal.
Imaging validation is the tell here.
If you have human PET/SPECT imaging with your tracer showing it gets to the tumor and nowhere else, you’ve de-risked a huge part of the radioligand development problem before dosing a single therapeutic patient.
Every Pb-212 program lives or dies on biodistribution. *Kidney accumulation is what kills most radioligand programs in Phase 1.
AlphaGen’s two Pb-212 programs
AG1206 — FAP radioligand
Macrocyclic peptide · picomolar binding · targets tumor microenvironment
AG1002 — SSTR2 radioligand
Non-agonist · targets tumor cells directly
Both programs use Pb-212 as the alpha emitter
The second program, AG1002, is a non-agonist radioligand targeting SSTR2.
SSTR2 is the same target Novartis’s Lutathera (177Lu-DOTATATE) and RadioMedix’s AlphaMedix (212Pb-DOTAMTATE) are hitting.
Going “non-agonist” is AlphaGen’s differentiator.
The argument is that non-agonists can bind more receptor sites on the tumor surface without triggering receptor internalization kinetics that are optimized for agonists, giving you higher tumor uptake per dose.
Whether that argument holds up in patients is a Phase 1 question. But it’s a legitimate mechanistic hypothesis, not a vibes-based differentiation.
The Biotech Voyager
Early-stage biotech signals, personalized.
The signals that matter to you, contextualized and written directly to you, so you cut through the noise and immediately understand why it matters.
AlphaGen hasn’t disclosed clinical trial phases, regulatory designations, or partnership terms.
They’re early, and they’re Chinese, which means you’ll most likely see IND filings in China first before anything moves to the US.
That’s been the playbook for the whole Asian radioligand cohort.
The elephant in the room – for ANY radiopharma company – is supply chain.
Pb-212 has historically been hard to make in clinical quantities, which is why Bicycle went to the UK’s Nuclear Decommissioning Authority for uranium. AlphaGen hasn’t said where their Pb-212 is coming from. That’s either a non-issue (they’ve got a supplier locked up) or a bigger problem than the chemistry.
Still, two programs, dual targeting strategies (tumor cell for SSTR2, tumor microenvironment for FAP), imaging already done on the lead.
If Pb-212 really is the future of alpha therapy and not another decade-long infrastructure problem, AlphaGen may be positioned to be part of the answer.
