Evalution of Iron Species in Healthy Subjects treated with Generic and Reference Sodium Ferric Gluconate | Apply Online

Frequently Asked Questions (FAQs)

What is the focus of FDA opportunity RFA-FD-14-019?

This FDA cooperative agreement focuses on a safety and equivalence question for intravenous (parenteral) iron drugs, specifically sodium ferric gluconate products used to treat anemia (including in settings such as chronic kidney disease). The project aims to generate well-controlled, prospective human data comparing a generic sodium ferric gluconate product with the reference listed drug.

Why are intravenous iron products treated differently than simple small-molecule drugs?

These iron injections are complex colloidal nanoparticles: carbohydrate-stabilized iron oxyhydroxide particles dispersed in water. Because they are nanoparticle-based colloids rather than simple molecules, their in vivo handling and release characteristics can be more complex, raising questions about whether conventional equivalence approaches fully capture clinically relevant differences.

What biological concern is central to this grant?

The key concern is the formation of non-transferrin bound iron (NTBI) if iron appears in plasma faster than transferrin can bind it, or if a product releases iron too readily. NTBI is viewed as potentially harmful because it can drive oxidative reactions that generate free radicals, contributing to oxidative stress, inflammation, and possibly tissue damage.

What happens to these iron particles after IV administration?

After intravenous dosing, the particles are taken up by phagocytic cells. Iron is processed inside lysosomes, then either stored (as ferritin or hemosiderin) or released back into circulation where it is carried by transferrin to where it is needed.

How does this opportunity relate to generic drug approval?

The opportunity is framed as post-market surveillance and as a way to strengthen confidence in FDA standards for approving generic versions of complex nanoparticle iron products. The underlying premise is that a properly approved generic should not produce meaningfully different NTBI levels compared with the brand/reference product.

What products are being compared in the proposed human study?

The main objective is to directly compare blood iron species after IV administration of a generic sodium ferric gluconate versus the reference sodium ferric gluconate in healthy volunteers.

Which iron measurements are expected in the clinical portion of the project?

The study is expected to measure plasma total iron (TI), transferrin-bound iron (TBI), and non-transferrin bound iron (NTBI), generating comparative time-course data after dosing.

Does the opportunity include evaluation of oxidative stress or toxicity signals?

Yes. In addition to TI, TBI, and NTBI, the work includes evaluation of oxidative stress and toxicity signals using in vitro and in vivo biomarkers. Examples mentioned include malondialdehyde (a lipid peroxidation marker) and heme oxygenase-1 (HO-1) RNA (a stress-response marker), while allowing other justified biomarkers.

What clinical study design does FDA prefer for this project?

The preferred design is a prospective, randomized, two-way crossover study in healthy subjects. Each participant receives both products in separate periods, with the sequence randomized. This is intended to reduce variability and improve the ability to detect true product-related differences.

What is expected during the washout period in the crossover design?

During washout, the protocol is expected to monitor markers such as transferrin-bound iron (TBI), total iron binding capacity, and serum ferritin to confirm that iron transport and storage markers return to baseline before the next dosing period. This helps ensure cleaner interpretation of NTBI and related endpoints.

What are the major project components described in the opportunity?

The described work blends product characterization, method development, clinical sampling, and biomarker evaluation. Expectations include obtaining marketed lots of both products; comparing quality attributes such as potency and impurities (and potentially other relevant physicochemical characteristics); developing/refining bioanalytical methods for TI/TBI/NTBI; running the randomized crossover study; assessing oxidative stress/toxicity biomarkers; monitoring adverse events; and conducting appropriate statistical analyses, with emphasis on NTBI.

Why does the opportunity emphasize bioanalytical method development for NTBI?

Accurately quantifying TI, TBI, and NTBI in plasma is described as a nontrivial analytical challenge because iron species can interconvert and assays can be sensitive to sample handling. The opportunity therefore expects applicants to develop or refine methods capable of reliable measurement.

What kinds of product characterization are expected before or alongside the clinical study?

Applicants are expected to obtain marketed lots of both the brand/reference and the generic sodium ferric gluconate and compare quality attributes such as potency and impurities, and potentially other physicochemical characteristics relevant to nanoparticle behavior.

Are adverse events and side effects part of the study expectations?

Yes. The opportunity explicitly includes closely monitoring participants for adverse events and side effects throughout the study.

What role does statistical analysis play in the project?

Applicants are expected to apply appropriate statistical analyses to determine whether observed differences between the generic and reference products are statistically significant, with particular emphasis on NTBI (but not limited to NTBI).

Why does FDA cite international experience and EMA discussions in this announcement?

FDA notes reports and public concerns about generic iron colloids in European and Asian markets, including concerns raised in citizen petitions about whether conventional equivalence approaches are sufficient for nanoparticle iron products. The European Medicines Agency (EMA) also issued a 2011 reflection paper suggesting some generic nanoparticle iron formulations might contain more labile iron, potentially increasing NTBI and oxidative stress. The funding opportunity aims to generate well-controlled human data to help bridge these perspectives and validate or challenge equivalence assumptions.

What is the funding mechanism used for this opportunity?

The opportunity uses a cooperative agreement mechanism. This typically implies substantial agency involvement during the project compared with a standard grant.

Which CFDA program is associated with this funding opportunity?

The opportunity is listed under CFDA 93.103 (FDA Research).

What were the key dates for this announcement?

The announcement was posted April 18, 2014. The original and final closing date was June 19, 2014. The archive date was July 19, 2014.

How many awards were anticipated?

The opportunity anticipated a single award (Expected Awards: 1).

What was the expected award amount?

The anticipated award range was roughly $450,000 to $500,000 for the cycle described.

Was cost-sharing required?

No cost-sharing requirement was stated in the opportunity description provided.

What was the total funding level mentioned, and how should it be interpreted alongside the single award?

The notice lists an estimated total funding level of $15,000,000, but also indicates a single expected award and provides ceiling/floor figures of roughly $450,000 to $500,000. Based on the provided description, the project for that cycle is intended to be funded within the stated per-award range.

Who was eligible to apply?

Eligibility was described as broad, including for-profit organizations (including small businesses), nonprofits, tribal entities, and many levels of government and higher education. Foreign recipients were also listed as eligible.

What is the overall purpose of the work from FDA's perspective?

The core purpose is to produce rigorous comparative human data on NTBI and oxidative stress after brand versus generic sodium ferric gluconate, helping FDA assess whether current generic approval standards adequately protect patients regarding labile iron release and downstream oxidative risk.