Structure Encountered

Parabilis Medicines

Clinical-stage biopharma developing stabilized helical peptide therapeutics for previously undruggable intracellular targets.

Regeneron paid $50M upfront + $75M equity + up to $2.2B milestones for Parabilis's Helicon platform via Antibody-Helicon Conjugates.

SIGNAL·Strategic collaboration + equity investment·$50M upfront + $75M equity + up to $2.2B milestones·SCORE 88·19 MAY 2026 · 12:47 UTC

● CAPTURE — IMAGE INCOMINGFRAME 01 / 01

Structure Parabilis Medicines, captured by Voyager

STRUCT. / PARABILIS MEDICINES

/ Cambridge, Massachusetts, United States

CAPT. / 19.05.26 12:47:05Z

SIGNAL / 88 / 100

Image relayed by The Biotech Voyager during pass over structure Parabilis Medicines. Resolution as transmitted.

001Vital Statistics

DATA LOCKED

Designation

Parabilis Medicines

Coordinates

Cambridge, Massachusetts, United States

Stage

Phase 2

Type

Therapeutics

Modalities

peptide · helical peptide · antibody-peptide conjugate

Therapeutic area

Oncology

002Signature Detected

FUNDING EVENT

Event type

Strategic collaboration + equity investment

Magnitude

$50M upfront + $75M equity + up to $2.2B milestones

Lead investor

Regeneron Pharmaceuticals

Participating

5 initial targets, Regeneron options for additional targets, plus stand-alone Helicon peptides

Use of capital

Advance Antibody-Helicon Conjugates and stand-alone Helicon peptide programs alongside zolucatetide Phase 1/2 program.

003Architecture

PLATFORM PROFILE

Target class

Intracellular protein-protein interactions traditionally considered undruggable. Helicon peptides are stabilized cell-penetrant alpha-helices that engage flat protein surfaces lacking conventional small-molecule binding pockets, delivered intact via antibody-mediated cell entry in the AHC format.

Differentiator

Antibody-drug conjugates put cytotoxic small molecules inside cells. Parabilis's Antibody-Helicon Conjugates put stabilized cell-penetrant alpha-helical peptides inside cells. The peptides hit intracellular protein-protein interactions that small molecules cannot drug, the same kind of biology zolucatetide is already pursuing for \u03b2-catenin:TCF. Pairing them with Regeneron's VelocImmune antibodies adds tumor-selective delivery.

Lead asset

Zolucatetide (FOG-001), \u03b2-catenin:TCF direct inhibitor, Phase 1/2 NCT05919264 (n=575). AHC platform now adds 5 Regeneron-collab targets.

Pipeline depth

Clinical: zolucatetide (Phase 1/2, FDA Orphan + Fast Track for desmoid). Preclinical: ERG degraders, allosteric ARON for prostate cancer. Platform extension: AHCs with Regeneron across 5+ targets.

004Voyager Assessment

MACHINE-GENERATED

Five months after $305M Series F, Parabilis pulled $50M upfront plus a $75M equity check from Regeneron, with up to $2.2B in milestones. The Helicon peptide platform is being extended from one clinical asset (zolucatetide in Phase 1/2) to five new targets via Antibody-Helicon Conjugates with Regeneron's VelocImmune antibodies. Parabilis kept ownership of both the conjugates and stand-alone Helicons. Regeneron rarely does external platform deals at this size, which says something about how the in-house ADC bench reads the intracellular peptide opportunity.

005Adjacent Structures

FRONTIER MAP

Regeneron Pharmaceuticals· VelocImmune platform partnerC4 Therapeutics, Inc.· degrader-antibody conjugate, RocheIterion Therapeutics· Wnt pathway porcupine inhibitorDaiichi Sankyo· ADC payload chemistry incumbentFoghorn Therapeutics· Foghorn lab Parabilis spinout originOrum Therapeutics· DAC platform competitorPeptiDream· intracellular peptide therapeutics

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