Partnership Proposal

Verzenio works.
It just can't reach
30% of your patients.

We've solved the blood-brain barrier problem for abemaciclib. The question is whether we solve it together — or separately.

60^×

Increase in abemaciclib M20 brain penetration when P-gp & BCRP are inhibited — confirmed in knockout mouse models.

This is not an incremental PK improvement. This is the difference between sub-therapeutic and therapeutic concentrations in the brain. Our bioavailable elacridar formulation replicates this effect orally, chronically, and safely.

The Problem You Know

30% of HR+/HER2− metastatic breast cancer patients develop brain metastases. When they do, Verzenio — your $5.7B drug — achieves a 6% intracranial response rate.

Not because abemaciclib doesn't work in the brain. It does. The Phase 1 glioblastoma data confirmed CSF penetration. The problem is P-glycoprotein and BCRP at the blood-brain barrier actively ejecting the drug before it can reach therapeutic concentrations. This is a transporter problem, not a biology problem.

The Solution We Built

Elacridar has been the gold-standard dual P-gp/BCRP inhibitor in research for two decades. Its clinical development stalled for one reason: catastrophically poor oral bioavailability. You can't chronically dose a patient with a drug that won't absorb.

We solved it. Our lipid nanoparticle / microemulsion platform achieves systemic elacridar exposure sufficient to fully inhibit BBB efflux transporters — orally, once-daily, at well-tolerated doses. Phase I safety data is clean. The formulation is patent-protected through 2041.

What This Means for Lilly

A co-formulated Verzenio + elacridar tablet, dosed to patients with or at risk of breast cancer brain metastases, would be the first CDK4/6 inhibitor approved for this indication.

Backed by independent P-gp/BCRP knockout data and our clinical-stage formulation, a Phase 1b/2 programme with CSF pharmacokinetic endpoints could deliver proof-of-concept within 24–30 months. This is a new indication, new IP, new pricing tier — and a defence of the Verzenio franchise against the generic cliff arriving in 2033.

$5.7B

Verzenio FY2025
worldwide revenue

~30%

HR+/HER2− MBC patients
who develop brain mets

~2033

Verzenio core
patent LOE

2041

Our formulation
patent expiry

Why Partner Now

The window is specific. And it won't stay open.

Verzenio's LOE is 2033. A combination product requires 6–8 years of development. The arithmetic is unambiguous: a partnership decision made in 2026 is the last opportunity to launch a CDK4/6 + elacridar combination under Verzenio's commercial infrastructure — with your sales force, your oncologist relationships, and your Verzenio brand equity intact. Wait two years and the window closes. We are also in active discussions with two other major oncology companies around selpercatinib and next-generation KRAS inhibitors. The exclusive opportunity on abemaciclib is time-limited.

What We're Proposing

Co-development agreement: Lilly funds Phase 1b/2; BBB-X provides formulation, IP licence, and scientific leadership
BBB-X retains manufacturing rights for bioavailable elacridar component; Lilly handles commercial combination product
Milestone-based deal structure: upfront + Phase 1b readout + Phase 3 initiation + regulatory approval
Royalty on combination net sales; Lilly retains full abemaciclib commercial rights
Option to licence BBB-X platform across Lilly pipeline (Retevmo, imlunestrant, olomorasib) at pre-agreed terms
Joint patent filings on combination, method-of-use, and dosing regimen — protecting both parties to 2040+

"You built one of the greatest oncology franchises of the decade. We built the key to unlock the one place it can't yet reach. Together, we finish the job for the 30% of patients Verzenio currently fails in the brain — and we extend that franchise a decade beyond the patent cliff."

Next Step

Request a scientific briefing

bd@bbbx-therapeutics.com · +44 1865 000 000

Verzenio works. It just can't reach30% of your patients.

Verzenio works.
It just can't reach
30% of your patients.