List of Excipients in Branded Drug PRALATREXATE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Fresenius Kabi USA LLC	PRALATREXATE	pralatrexate	65219-550	HYDROCHLORIC ACID
Fresenius Kabi USA LLC	PRALATREXATE	pralatrexate	65219-550	SODIUM CHLORIDE
Fresenius Kabi USA LLC	PRALATREXATE	pralatrexate	65219-550	SODIUM HYDROXIDE
Fresenius Kabi USA LLC	PRALATREXATE	pralatrexate	65219-550	WATER

Generic Drugs Containing PRALATREXATE

Company	Ingredient	NDC	Excipient
DrReddy's Laboratories Inc	pralatrexate	43598-342	HYDROCHLORIC ACID
DrReddy's Laboratories Inc	pralatrexate	43598-342	SODIUM CHLORIDE
DrReddy's Laboratories Inc	pralatrexate	43598-342	SODIUM HYDROXIDE
DrReddy's Laboratories Inc	pralatrexate	43598-342	WATER

What are the Most Frequently-Used Excipients in PRALATREXATE?

# Of NDCs	Excipient
1	HYDROCHLORIC ACID
1	SODIUM CHLORIDE
1	SODIUM HYDROXIDE
1	WATER

Pralatrexate Excipient Strategy and Commercial Opportunities

Last updated: September 5, 2026

Pralatrexate is a niche oncology injectable marketed in the United States as Folotyn for relapsed or refractory peripheral T-cell lymphoma (PTCL). Its commercial profile is defined by a narrow indication, intravenous administration, a simple aqueous formulation, and limited competition. The main excipient opportunities are not conventional reformulation of the active ingredient. They are dose-convenience improvements, stability enhancement, ready-to-use presentations, reduced preparation waste, and differentiated packaging for oncology pharmacies.

The current formulation uses pralatrexate at 20 mg/mL in a sterile aqueous solution containing sodium chloride, hydrochloric acid, sodium hydroxide, and water for injection. The product is administered as an intravenous push over three to five minutes after dilution in 0.9% sodium chloride injection. Patients also receive folic acid and vitamin B12 supplementation to reduce treatment-related toxicity (FDA, 2009; DailyMed, 2024).

What is the current FDA-approved formulation of pralatrexate?

Folotyn is a preservative-free, single-dose, sterile solution for intravenous administration. The labeled strengths are 20 mg/1 mL and 40 mg/2 mL vials, both at a concentration of 20 mg/mL.

Formulation attribute	Current product
Active ingredient	Pralatrexate
Strength	20 mg/mL
Presentations	20 mg/1 mL and 40 mg/2 mL single-dose vials
Route	Intravenous
Administration	IV push over 3 to 5 minutes
Diluent	0.9% sodium chloride injection
pH control	Hydrochloric acid and sodium hydroxide
Tonicity agent	Sodium chloride
Vehicle	Water for injection
Preservative	None identified in the U.S. label
Storage	Refrigerated storage under labeled conditions
Indication	Relapsed or refractory PTCL

The formulation is commercially efficient because it avoids a lyophilization cycle, reconstitution step, and separate diluent vial. Its limitations are the need for cold-chain storage, aseptic dose preparation, a single-use vial format, and a narrow concentration range for weight-based dosing.

Pralatrexate is a folate analog metabolic inhibitor. The drug is dosed at 30 mg/m² once weekly for six weeks in seven-week cycles under the approved regimen. The product label requires folic acid and vitamin B12 supplementation, which affects the complete treatment-support package but does not make those vitamins pharmaceutical excipients in the injectable product.

What excipients are protected or commercially important for pralatrexate?

The current excipient system is simple and presents limited composition-of-matter opportunity. Sodium chloride controls tonicity, while hydrochloric acid and sodium hydroxide establish the target pH. Water for injection is the vehicle.

The commercially relevant formulation variables are:

1. pH range and buffer selection.
2. Pralatrexate concentration.
3. Container closure compatibility.
4. Light protection.
5. Adsorption to administration materials.
6. Dilution stability in normal saline.
7. Particulate control.
8. Refrigerated versus room-temperature stability.
9. Ready-to-administer packaging.
10. Reduced residual volume and overfill.

A new composition patent would generally require more than replacing hydrochloric acid or sodium hydroxide with another pH adjuster. Those changes may support patentability only if they produce an unexpected result, such as materially improved chemical stability, lower impurity formation, reduced adsorption, improved compatibility with infusion materials, or extended room-temperature storage.

Potential excipient platforms

Platform	Commercial objective	Likely development value
Buffered aqueous solution	Improve pH control during storage and dilution	Moderate
Stabilized concentrated solution	Reduce vial volume and preparation burden	Moderate to high
Ready-to-use syringe or cartridge	Reduce pharmacy manipulation	High operational value
Room-temperature formulation	Reduce cold-chain costs	High, if stability is demonstrated
Lyophilized powder	Improve long-term stability	Moderate, but adds reconstitution burden
Polymer or surfactant system	Reduce adsorption or aggregation	Low to moderate unless a defined problem exists
Larger multi-dose vial	Reduce packaging cost	Low, because preservative and sterility issues arise
Closed-system transfer-compatible vial	Reduce occupational exposure and waste	Moderate
Prefilled infusion container	Reduce preparation time	High for institutional purchasers

A ready-to-use presentation is likely more commercially attractive than a complex excipient system. Oncology pharmacies value reduced manipulations, predictable dose withdrawal, lower preparation time, and lower risk of product loss. The main technical question is whether pralatrexate remains stable in a syringe, cartridge, or infusion container over the proposed shelf life.

What formulation patents protect pralatrexate?

Publicly available product information identifies Folotyn as the marketed pralatrexate product, but the commercial value of the current product is not dependent solely on an active-ingredient patent. The relevant protection categories include:

• Pralatrexate composition and synthesis patents.
• Pharmaceutical compositions containing pralatrexate.
• Methods of treating lymphoma with pralatrexate.
• Dosing regimens based on body-surface area.
• Folic acid and vitamin B12 supplementation protocols.
• Sterile injectable formulations.
• Stability and storage conditions.
• Container-closure systems.
• Manufacturing and purification processes.

The original active-ingredient and therapeutic-use patent estate is likely less important today than formulation, process, regulatory, and commercial barriers. Pralatrexate was approved in 2009, so basic patent protection associated with early discovery work is unlikely to provide a long remaining term absent patent-term adjustment or later-filed improvements.

A precise current patent-expiration analysis requires matching each patent to the FDA Orange Book entry, patent-term adjustment, pediatric exclusivity, terminal disclaimers, and any continuation claims. The product label does not itself establish the complete patent estate. Patent records must be reviewed through the USPTO, FDA Orange Book, and court dockets.

What is the Orange Book status of Folotyn and pralatrexate?

Folotyn is an FDA-approved prescription oncology product. It is a small-molecule injectable, not a biologic, and therefore does not create a biosimilar pathway under the Public Health Service Act.

The regulatory pathway for a competing product would generally be an abbreviated new drug application if the applicant can establish pharmaceutical equivalence and bioequivalence. A generic injectable could face fewer clinical development requirements than a new drug, but it would still need to demonstrate:

• The same active ingredient.
• The same route of administration.
• Comparable strength and dosage form.
• Sterility and injectable quality.
• Adequate chemistry, manufacturing, and controls.
• Container-closure suitability.
• Labeling conformity, subject to lawful carve-outs for protected methods of use.
• Bioequivalence or an FDA-accepted alternative for an injectable product.

The practical Orange Book question is whether any listed patents or regulatory exclusivities block an ANDA applicant. Because Folotyn is a small-molecule drug, Paragraph IV certification is the relevant challenge mechanism if an applicant asserts that a listed patent is invalid, unenforceable, or not infringed.

When does pralatrexate lose exclusivity?

The key regulatory milestones are:

Event	Date or status
FDA approval of Folotyn	September 24, 2009
Initial indication	Relapsed or refractory PTCL
New chemical entity exclusivity	Five years from approval, subject to statutory exceptions
Orphan-drug exclusivity	Seven years from approval for the approved orphan indication
Patent protection	Depends on individual patent, adjustment, and continuation status
Generic pathway	ANDA, subject to applicable Orange Book patents
Biosimilar pathway	Not applicable

The seven-year orphan exclusivity period from the 2009 approval would have expired in 2016. Five-year new chemical entity exclusivity also would have expired no later than 2014, subject to the timing of any Paragraph IV filing and statutory effects. Current market protection therefore depends primarily on patents, product quality requirements, manufacturing know-how, supply reliability, and the economics of serving a small oncology market.

An orphan product can remain commercially protected after formal exclusivity ends if the market is too small to attract multiple generic entrants. That protection is commercial rather than statutory.

What generic entry risks exist for Folotyn?

Generic entry risk is moderate in technical terms and uncertain in commercial terms.

The formulation is aqueous and relatively simple. That supports generic development. Injectable products, however, impose stringent requirements for sterility, particulate matter, extractables and leachables, container closure, stability, and manufacturing validation. Pralatrexate is also a potent cytotoxic oncology drug, which increases facility, containment, worker-safety, and waste-handling requirements.

Likely generic launch scenarios

Scenario	Market effect
One approved generic	Price pressure, but limited erosion if supply is constrained
Two or three entrants	Material price erosion and hospital contracting pressure
Several entrants	Rapid price compression and possible supply instability
Authorized generic	Faster commercial response and controlled price segmentation
No entrant	Continued premium pricing supported by niche demand and manufacturing complexity

For a generic applicant, the commercial opportunity is constrained by the size of the PTCL population, physician familiarity with Folotyn, reimbursement dynamics, and the need to establish institutional contracts. A technically approvable product may still have weak returns if annual demand does not support dedicated manufacturing and distribution costs.

Which companies are challenging pralatrexate exclusivity?

No broad, high-profile Paragraph IV litigation campaign against Folotyn is established in the core public record comparable to major blockbuster drug challenges. The absence of visible litigation does not eliminate future ANDA risk. Niche injectables often attract challenges only when a manufacturer has confirmed demand, validated a sterile supply chain, and determined that the reference product price supports entry.

Potential competitors include:

• Specialty generic manufacturers with oncology injectable capacity.
• Contract manufacturers with cytotoxic containment capabilities.
• Companies with existing hospital oncology portfolios.
• Regional suppliers seeking a niche injectable product.
• A current or former commercial partner seeking lifecycle control.

The most relevant competitive signal would be an ANDA filing, a Paragraph IV notice, an FDA tentative approval, or a product-specific patent dispute. Standard generic entry under Paragraph III or after patent expiration would create less litigation exposure.

How strong is the pralatrexate patent estate?

The patent estate is likely moderate to weak for basic composition protection and potentially stronger for later formulation or manufacturing claims, depending on the validity and remaining term of specific patents.

Strength factors

• Injectable products can support narrow but enforceable formulation claims.
• Manufacturing claims may be difficult to design around if they cover high-purity or stereochemically controlled pralatrexate.
• Orphan-market economics can reduce the number of actual challengers.
• Regulatory and quality burdens raise the cost of entry.

Weakness factors

• The product has been marketed since 2009.
• The core drug substance is mature.
• The labeled excipient system is conventional.
• Small-molecule ANDA competition is legally available.
• Simple aqueous formulations are often vulnerable to obviousness and design-around arguments.
• Orphan exclusivity has expired.

The strongest lifecycle claims would likely involve a demonstrated stability advantage, a particular concentration range, a low-impurity profile, a container system, or a manufacturing process that materially improves yield or quality.

What manufacturing and IP barriers affect pralatrexate?

Pralatrexate manufacturing requires control of the drug substance, sterile filling, cytotoxic containment, and quality systems appropriate for injectable oncology products. The main barriers are operational rather than purely legal.

Manufacturing barriers

• Handling of a cytotoxic active pharmaceutical ingredient.
• High-potency containment during dispensing and filling.
• Sterile filtration or aseptic processing.
• Control of particulate matter.
• Stability-indicating analytical methods.
• Compatibility with vial elastomers and seals.
• Validation of cleaning and cross-contamination controls.
• Reliable supply of specialized oncology packaging.
• Disposal of cytotoxic waste.

IP and regulatory barriers

• Process patents covering synthesis or purification.
• Formulation patents covering pH, concentration, or stabilizers.
• Method-of-use patents requiring label analysis.
• Trade secrets related to impurity control.
• Regulatory exclusivity associated with later supplements, if any.
• Orange Book patent listing and Paragraph IV litigation risk.

A competitor can often avoid formulation patents by using a different pH-adjustment system or concentration. That strategy can create new development risk if the alternative formulation has inferior stability or requires a different administration procedure.

What excipient strategies offer the best commercial opportunity?

The strongest opportunity is a differentiated presentation that reduces pharmacy labor without adding clinical complexity.

1. Room-temperature stable concentrate

A formulation stable at controlled room temperature could reduce refrigerated storage, improve distribution, and reduce product loss. The development burden is substantial because the formulation must maintain potency, impurity limits, clarity, sterility assurance, and container compatibility.

2. Ready-to-administer syringe

A prefilled syringe could eliminate vial withdrawal and reduce manipulation. The principal barriers are dose flexibility, syringe-material compatibility, extractables and leachables, labeling, transport qualification, and the need to support body-surface-area dosing.

3. Pharmacy-ready infusion container

A premixed container in 0.9% sodium chloride could reduce preparation time and improve dose standardization. This presentation may have stronger institutional value than a prefilled syringe because it aligns directly with administration workflow.

4. Lower-volume concentrated vial

A higher concentration could reduce vial count and waste for larger doses. It would require evidence that the product remains stable and can be administered safely without local irritation, dosing errors, or unacceptable dilution behavior.

5. Cytotoxic-handling package

A vial and transfer system designed for closed-system drug-transfer devices could create commercial differentiation even if the liquid formulation remains unchanged. The value would come from reduced exposure risk and pharmacy workflow compatibility.

How does pralatrexate compare with competing PTCL treatments?

Pralatrexate competes with brentuximab vedotin, romidepsin, belinostat, chemotherapy regimens, and newer targeted therapies depending on disease subtype and treatment history. Unlike brentuximab vedotin, pralatrexate is a small molecule and does not face biosimilar competition. Unlike oral agents, it requires oncology infusion-center or hospital administration.

Product	Modality	Administration	Competition risk
Pralatrexate	Small-molecule antifolate	IV push	Generic injectable risk
Brentuximab vedotin	Antibody-drug conjugate	IV infusion	Biosimilar and clinical-positioning risk
Romidepsin	Small-molecule HDAC inhibitor	IV infusion	Generic or treatment-choice competition
Belinostat	Small-molecule HDAC inhibitor	IV infusion	Generic injectable risk
Oral targeted therapies	Small molecules	Oral	Convenience and reimbursement competition

Pralatrexate's main product disadvantage is administration burden. Its main formulation opportunity is therefore convenience rather than a new therapeutic mechanism.

What is the revenue exposure and commercial outlook?

Standalone Folotyn revenue is not consistently disclosed as a separate public line item by the product's commercial owner. The addressable population is limited to relapsed or refractory PTCL, and treatment duration varies by response, toxicity, and clinical status. Revenue is therefore more sensitive to market access, treatment sequencing, and specialist adoption than to broad oncology prevalence.

Commercial value can be expanded through:

• Preferred formulary placement.
• Reduced preparation and administration costs.
• Lower vial waste.
• Improved inventory flexibility.
• Regional hospital contracts.
• Specialty pharmacy or oncology-network distribution.
• Lifecycle exclusivity around a differentiated presentation.
• International registration using a stable, transport-friendly formulation.

The most defensible commercial strategy is a lifecycle product with measurable workflow benefits, supported by a formulation patent and a device or packaging advantage where possible.

What patent litigation and settlement issues affect pralatrexate?

No major publicly established settlement framework defines the current U.S. pralatrexate market. If an ANDA applicant files a Paragraph IV certification against a listed patent, the reference sponsor may bring an infringement action within 45 days of receiving notice. That filing can trigger a 30-month stay of FDA approval under the Hatch-Waxman framework, subject to statutory exceptions and court developments.

A settlement could include:

• A licensed generic entry date.
• An authorized generic arrangement.
• Restrictions on launch timing.
• Supply or manufacturing terms.
• A covenant not to sue.
• Resolution of formulation or method-of-use claims.

Any settlement analysis should distinguish between a patent covering the drug substance, a formulation patent, and a method-of-use patent. Method-of-use claims may be addressed through label carve-outs, while composition claims generally present a broader barrier.

Key Takeaways

• Pralatrexate is marketed as Folotyn, a 20 mg/mL preservative-free aqueous IV solution.
• The current excipients are sodium chloride, hydrochloric acid, sodium hydroxide, and water for injection.
• Orphan and new chemical entity exclusivity have expired; remaining protection depends on specific patents and commercial barriers.
• Pralatrexate is a small molecule, so biosimilar competition does not apply.
• Generic injectable entry is technically feasible but constrained by cytotoxic handling, sterile manufacturing, limited market size, and hospital contracting.
• The strongest excipient opportunities are room-temperature stability, ready-to-use packaging, premixed infusion containers, and reduced pharmacy manipulation.
• A simple excipient substitution is unlikely to create durable protection without a demonstrated stability, compatibility, or workflow advantage.
• The most valuable lifecycle product would combine a differentiated formulation with a container, device, or pharmacy-process benefit.
• Standalone product revenue is not reliably disclosed, so commercial modeling should use patient volume, dose intensity, treatment duration, and price assumptions rather than reported segment revenue.

FAQs

Can pralatrexate be reformulated as an oral drug?

An oral pralatrexate product would require a new development program addressing bioavailability, food effects, dose proportionality, toxicity, and clinical equivalence. It would not be a routine excipient reformulation of Folotyn.

Is pralatrexate compatible with normal saline?

The approved product is diluted in 0.9% sodium chloride injection before administration. Any alternative diluent or extended in-use storage period requires supporting compatibility and stability data.

Would a lyophilized pralatrexate product be commercially attractive?

A lyophilized product could improve shelf stability but would add reconstitution steps, increase pharmacy labor, and create additional particulate and reconstitution risks. It is less attractive than a stable ready-to-use liquid unless the liquid formulation cannot meet the target shelf life.

Can an ANDA applicant change pralatrexate excipients?

An ANDA applicant may use different inactive ingredients if FDA accepts the formulation and the product remains pharmaceutically equivalent, bioequivalent, safe, sterile, and appropriately labeled. A significant formulation change can increase regulatory and compatibility risk.

Does folic acid supplementation create a separate pralatrexate formulation opportunity?

Folic acid and vitamin B12 are required treatment-support measures under the Folotyn label, but they are not excipients in the injectable product. A coordinated supplementation kit could create commercial convenience, although it would involve separate regulatory, packaging, and reimbursement analysis.

References

1. DailyMed. (2024). FOLOTYN- pralatrexate injection, solution. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/

2. U.S. Food and Drug Administration. (2009). FDA approves Folotyn for relapsed or refractory peripheral T-cell lymphoma. https://www.fda.gov/

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

4. U.S. Food and Drug Administration. (2024). Hatch-Waxman Amendments and abbreviated new drug applications. https://www.fda.gov/drugs

5. National Cancer Institute. (2024). Pralatrexate. https://www.cancer.gov/

6. U.S. Patent and Trademark Office. (2024). Patent Center. https://patentcenter.uspto.gov/