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Basket 09 — Regulatory Strategy

US FDA
505(b)(2) Ideas

Active development programmes plus repurposing, new dosage form, new route, new combination and lifecycle extension opportunities under the US FDA 505(b)(2) pathway.

Status

Two named programmes in active development — Eltrombopag and Sucroferric Oxyhydroxide. Further concepts remain at opportunity stage pending internal review.

Concept Areas

New Dosage FormNew Route of AdministrationModified-Release ConceptFixed-Dose CombinationNew Strength or PackagingRepurposing / New Use Concept

The US FDA 505(b)(2) pathway is not a shortcut — it is a legitimate regulatory framework that allows new drug applications to rely, in part, on published literature or existing FDA drug approval findings for at least some portion of the evidence needed for approval. For a manufacturer with GMP-certified API capability and niche therapeutic focus, 505(b)(2) represents an entry mechanism into the US regulated market that does not require a full de novo clinical programme for each molecule.

In Development

Active programmes

Eltrombopag

Technology package complete — ready to transfer

Formulation Development & Technology Transfer

Class

Thrombopoietin Receptor Agonist (TPO-RA)

Reference Product

Promacta® / Revolade®

Dosage Form

Oral tablets — 12.5 mg, 25 mg, 50 mg, 75 mg

Availability

USA & Canada outlicensed — open for Europe and Australia

Eltrombopag is an oral thrombopoietin receptor agonist that stimulates platelet production, indicated in chronic immune thrombocytopenia, severe aplastic anaemia and thrombocytopenia associated with chronic hepatitis C. Polysacc has developed and optimised Eltrombopag tablets with a robust manufacturing process and a complete analytical package. Rights for the United States and Canada have already been outlicensed; commercialisation partners are now being sought for Europe and Australia.

Indications

Chronic immune thrombocytopenia (ITP)Severe aplastic anaemia (SAA)Hepatitis C-associated thrombocytopenia

Strategic Advantage

  • —Proven formulation with a fully characterised manufacturing process.
  • —Successful outlicensing already achieved for the USA and Canada.
  • —Ready-to-transfer technology package — a de-risked route to rapid market entry.
  • —Technical and regulatory support available throughout transfer.
  • —Flexible licensing models: commercialisation partnership or regional technology licensing.

Development Status

API qualificationCompleted
Formulation developmentCompleted
Analytical methodsCompleted
Process optimisationCompleted
Technology packageCompleted
Technology transferReady
Regulatory supportAvailable

Sucroferric Oxyhydroxide

Proof of concept complete — prototype under development

Oral Liquid Reformulation

Class

Iron-based phosphate binder

Reference Product

Velphoro® (chewable tablet)

Dosage Form

Oral liquid — reformulation of the approved chewable tablet

Availability

Open for out-licensing, co-development or technology transfer

Sucroferric oxyhydroxide binds dietary phosphate in the gastrointestinal tract, lowering serum phosphate in end-stage renal disease patients on dialysis. Because iron uptake from the complex is minimal, it avoids the iron-overload risk carried by other iron-based binders. The approved product exists only as a chewable tablet — a form poorly suited to the elderly, frail and dialysis-dependent population that actually takes it. Polysacc is developing an oral liquid to address that gap, pursuing a US FDA 505(b)(2) application with an EU Article 10(3) hybrid application as the parallel route.

Indications

Hyperphosphataemia in chronic kidney diseaseEnd-stage renal disease patients on dialysis

Reformulation Rationale

  • —Taste and staining: the iron-based chewable tablet is unpalatable and discolours the tongue and teeth, which works against long-term adherence.
  • —Administration burden: most CKD dialysis patients are elderly, frequently bedridden or physically weakened, and cannot reliably chew a tablet at every meal.
  • —Moisture sensitivity: the molecule degrades in simple powder form, producing inconsistent dosing and under-dosing risk.
  • —An oral liquid resolves all three — easy to swallow, dose-accurate despite moisture sensitivity, and amenable to effective taste masking.

Development Status

Proof of concept — bench-scale batchesCompleted
Analytical methodsCompleted
Provisional patent applicationSubmitted
Complete specification — early publication requestIn process
Prototype developmentIn progress
In vitro protein binding studiesPlanned

Market Context

Phosphate Binder Market

$3.5BnGlobal phosphate binder market value, 2024
4–5%Projected market CAGR through 2028
15–20%Sucroferric oxyhydroxide share of the binder market

Market Share by Binder Class

Sevelamer (carbonate / hydrochloride)35–40%
Lanthanum carbonate20–25%
Sucroferric oxyhydroxide15–20%
Other phosphate binders10–15%

North America leads in usage, followed by Europe and Asia-Pacific where CKD incidence is rising. The reference product is protected by Orange Book-listed patents expiring between May 2029 and May 2035, several of which remain in active litigation — timing the reformulation entry window is a core part of the programme strategy.

Engagement

Partnering models

ModelPolysacc's RolePartner's RoleRevenue for Polysacc
Out-LicensingProvide IP, patent and product conceptDevelop, register, manufacture and commercialiseUpfront, milestones and royalties on sales
Co-DevelopmentShare R&D and IP, co-invest in developmentShare development, regulatory and manufacturingRevenue or profit share, commercialisation rights split
Technology TransferProvide detailed technology and assist transferScale up, validate and manufactureTech transfer fee plus optional supply or licence deals

Pathway Mechanics

Six regulatory opportunity types

New Dosage Form

Medium

Converting an existing approved drug into a new physical form — tablet to patch, solution to microsphere, immediate-release to modified-release. The 505(b)(2) pathway allows reliance on the safety and efficacy data of the reference listed drug (RLD), requiring only bridging studies for the new form.

Oral → transdermal, IM injectable → subcutaneous depot, immediate-release → extended-release capsule

New Route of Administration

Medium–High

Repurposing an approved molecule via a different delivery route that achieves a meaningfully different pharmacokinetic or clinical outcome. The regulatory argument centres on the new clinical benefit while retaining reliance on the known safety database of the parent compound.

Oral → intravesical, systemic → topical, IV → inhalation

Modified-Release Concept

Medium

Engineering the release kinetics of an approved molecule to reduce dosing frequency, smooth plasma concentration curves, reduce peak-related adverse effects, or achieve site-specific release. A well-characterised pharmacokinetic-pharmacodynamic model underpins the regulatory submission.

Once-daily formulation of a twice-daily molecule, gastric-retention systems, colon-targeted delivery

Fixed-Dose Combination

Medium–High

Combining two or more individually approved molecules into a single dosage form where the combination demonstrates additive or synergistic clinical value, simplifies treatment, or improves adherence meaningfully over co-administration. The 505(b)(2) route allows reliance on each component's existing approval while adding combination-specific bridging data.

Alpha-blocker + 5-ARI combination tablets, OCP combination optimisation, anti-emetic combinations

New Strength or Packaging

Low–Medium

Regulatory opportunities exist where an approved molecule lacks a clinically useful dose strength or patient-appropriate packaging format — paediatric doses, geriatric unit-dose packaging, or precision dose strengths for specific subpopulations.

Paediatric dosing strengths, geriatric blister unit doses, precision microdose formulations

Repurposing / New Use Concept

High — indication-specific trials required

Extending an approved molecule into a new indication where existing safety data supports the regulatory argument and the clinical evidence base is emerging. The 505(b)(2) pathway is ideally suited: the full safety database is inherited; only efficacy for the new indication requires demonstration.

IC/BPS indications for existing urological molecules, neuropathy adjunct use for metabolic drugs