# PLT+ Characterization and IND-Enabling Studies

> **NIH NIH R44** · STELLULAR BIO, INC. · 2021 · $952,100

## Abstract

PROJECT SUMMARY/ABSTRACT
Platelet BioGenesis has developed a millifluidic bioreactor that reproduces key features of the adult
bone marrow microenvironment to enable clinical-scale production of donor-independent platelets
(PLT+) from human induced pluripotent stem cells (hiPSCs). Based on guidance from the U.S. Food
& Drug Administration (FDA), the goal of this proposal is to perform safety and efficacy studies
following good laboratory practice (GLP) principles to support a regulatory package that will permit
clinical testing of our product. Platelets are essential blood components responsible for clot
formation and blood vessel repair. Low platelet count is a dangerous consequence of cancer
treatment, transplant, and surgery, and platelets are a critical first-line therapy to prevent
uncontrolled bleeding. Transfusion units are derived exclusively from human volunteer donors and
must be stored at ≥22°C to avoid irreversible activation/aggregation. Risk of bacterial growth limits
shelf life to 5 days, 3 of which are consumed by screening and transport. Because of these
limitations, blood centers often only have a 1.5-day inventory that is quickly depleted by
emergencies [1,2]. We have developed a 2-step ex vivo production platform in which hiPSCs
(replenishable progenitors that can be frozen for years) undergo differentiation into pre-
megakaryocytes (preMK+) that are banked and used for on-demand PLT+ generation in our
bioreactor. In our Phase II project, we successfully generated and characterized functional preMKs+
and PLTs+ from a qualified hiPSC line [3,4] using an established serum/feeder-free, scalable current
good manufacturing practice (cGMP)-compliant process [5]. After confirming PLT+ quality and function,
we verified hemostatic and thrombogenic potentials in vivo. Building on these results, this Phase IIB
SBIR proposal outlines three specific aims to perform GLP studies to 1) establish PLT+ release
criteria and storage profile, 2) assess teratoma risk in vivo, and 3) measure circulation and
clearance time in vivo. For all aims, human donor platelets will serve as a physiological benchmark
for comparison. Completion of these aims will facilitate submission of an Investigational New
Drug (IND) application.
Aim 1. Establish PLT+ release quality and storage profile. We will evaluate PLT+ biomarkers,
function, metabolic activity, and sterility under FDA-approved storage conditions.
Aim 2. Assess teratoma risk in mice. Following GLP guidelines, we will determine whether any risk
of tumorigenic growth is associated with PLT+ product in immunocompromised (NSG) mice.
Aim 3. Assess PLT+ circulation and clearance times in mice. We will assess the circulation
and clearance of PLT+ in immunocompromised (NSG) mice.

## Key facts

- **NIH application ID:** 10223403
- **Project number:** 5R44HL131050-04
- **Recipient organization:** STELLULAR BIO, INC.
- **Principal Investigator:** Bradford Dykstra
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $952,100
- **Award type:** 5
- **Project period:** 2016-04-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10223403

## Citation

> US National Institutes of Health, RePORTER application 10223403, PLT+ Characterization and IND-Enabling Studies (5R44HL131050-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10223403. Licensed CC0.

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