# Long-acting injectable tacrolimus for chronic immunosuppression

> **NIH NIH R44** · AURITEC PHARMACEUTICALS, INC. · 2023 · $1,023,600

## Abstract

PROJECT SUMMARY
The broad, long-term goal of this Direct to Phase II SBIR is to improve immunosuppression outcomes in organ
transplant recipients by developing a long-acting injectable calcineurin inhibitor (CNI). For more than two
decades, tacrolimus is a valuable pharmacological tool in the prophylaxis of organ transplant rejection. It is
commercially available as twice and once-daily oral pills. Oral formulations undergo first-pass metabolism and
suffer from low and variable bioavailability which in turn leads to high intra- and inter- patient pharmacokinetic
(PK) variability. Tacrolimus has a narrow therapeutic index, hence sub-therapeutic blood levels (<5 ng/ml)
results in organ rejection whereas supra-therapeutic levels (>15 ng/ml) are toxic. Daily dosing has been
associated with medication non-adherence. The medical costs transplant recipients with poor adherence are
~$30,000 higher than patients with high adherence at 3 years post-transplant. Thus, the three reported unmet
needs are higher medication adherence, better outcomes of graft survival, and linear PK profile.
Auritec Pharmaceuticals has developed a subcutaneous injectable formulation of tacrolimus that provides
consistent therapeutic blood levels of the drug for 30 days after a single administration. The product is based
on Auritec’s innovative Plexis technology that has shown clinical proof of concept in two Phase 1 trials. The
Plexis technology is differentiated from other long-acting injectable technologies in terms of its high drug
loading, scalable manufacturing process, and more linear release kinetics. The product has demonstrated safe
and sustained release of tacrolimus in a first-in-human safety/PK study using the “exploratory IND” approach.
PK modeling shows that a monthly dosing schedule can be readily achieved in transplant recipients to maintain
tacrolimus blood levels in the safe and efficacious range (5-15 ng/ml). The benefits of our product include 1)
complete medication adherence for 1 month after one administration; 2) fewer episodes of graft rejections; 3)
simpler dosing schedule, and; 4) a smooth PK profile without sub- or supra-therapeutic levels. The populations
anticipated to benefit from the product are: Patients who have demonstrated tolerability to tacrolimus but find it
challenging to adhere to a daily fixed schedule (such as younger patients) and/or rapid metabolizers of
tacrolimus. The end result will be a cost-effective maintenance therapy for maintenance therapy.
The specific aims of this Direct to Phase II SBIR are to perform activities in pursuit of a “traditional Phase 1
IND” allowance. The proposed work includes - manufacturing in accordance with current Good Manufacturing
Practices (cGMP); animal testing in compliance with Good Laboratory Practices (GLP); analytical method
development; Chemistry, Manufacturing and Controls (CMC) testing; and finally, IND submission to the FDA.
These efforts will result in an IND approval and allow for the first...

## Key facts

- **NIH application ID:** 10662560
- **Project number:** 5R44AI170362-02
- **Recipient organization:** AURITEC PHARMACEUTICALS, INC.
- **Principal Investigator:** Sarjan Shah
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $1,023,600
- **Award type:** 5
- **Project period:** 2022-07-08 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10662560

## Citation

> US National Institutes of Health, RePORTER application 10662560, Long-acting injectable tacrolimus for chronic immunosuppression (5R44AI170362-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10662560. Licensed CC0.

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