US Patent 8,735,392: Talazoparib Tosylate Crystal Form, Claim Scope, Expiration, and Patent Landscape
US Patent 8,735,392 protects a specific crystalline tosylate salt of talazoparib, the active ingredient in Pfizer’s Talzenna. The patent does not broadly claim talazoparib, every talazoparib salt, or every polymorph. Its core protection is a defined solid-state form identified through alternative analytical characteristics, including X-ray powder diffraction, solid-state carbon-13 NMR, thermal analysis, and moisture-uptake behavior.
The patent’s baseline expiration date is March 2, 2032, subject to any patent-term adjustment shown in the USPTO patent record. Talzenna received FDA approval in 2018 and is a small-molecule drug, so biosimilar pathways do not apply. Generic entry depends on the Orange Book patent listings, Paragraph IV certifications, litigation, settlements, and the ability of an ANDA applicant to avoid or invalidate the claimed crystalline form.
What drug and solid form does US Patent 8,735,392 protect?
The patent protects the tosylate salt of talazoparib in a particular crystalline form.
The chemical entity is:
(8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one tosylate
This is talazoparib tosylate, the salt form used for the marketed product. Talazoparib is a poly(ADP-ribose) polymerase, or PARP, inhibitor marketed by Pfizer as Talzenna.
The patent is directed to solid-state identity and quality attributes rather than pharmacology. It does not claim:
- The free-base talazoparib molecule as such.
- Every pharmaceutically acceptable salt of talazoparib.
- Every crystalline or amorphous form of talazoparib.
- A specific dosage strength.
- A specific capsule composition.
- A manufacturing process for producing the crystal.
- A method of treating breast or prostate cancer.
- A specific patient population.
Those subjects may be covered by separate patents or regulatory exclusivities.
What does claim 1 of US 8,735,392 cover?
Claim 1 covers the specified crystalline form of talazoparib tosylate when it exhibits at least one of six listed analytical characteristics.
| Analytical characteristic |
Claimed limitation |
| Solid-state 13C NMR |
Peaks at 143.2, 136.0, 131.8, 123.9, 112.2, 105.2, and 100.3 ppm, each within ±0.2 ppm |
| Differential scanning calorimetry |
Endotherm maximum between about 320°C and about 335°C |
| Thermogravimetric analysis |
Thermogram indicative of an unsolvated material |
| Dynamic vapor sorption |
No significant weight change from 0% to 95% relative humidity |
| XRPD d-values |
Peaks at approximately 11.9, 5.9, 4.9, 4.4, 4.3, 3.9, and 3.7 Å |
| XRPD 2θ values |
Peaks at 7.4°, 15.1°, 18.1°, 20.1°, 20.4°, 22.6°, and 24.0°, each within ±0.2° |
The phrase “at least one of” is significant. A material does not necessarily need to satisfy every listed analytical test to fall within the literal language of claim 1. On its face, the claim reaches the crystalline form if it exhibits any one of the specified categories.
That drafting approach creates a broad analytical perimeter but also raises proof issues. In an infringement dispute, the patent owner would need to establish that the accused material is the claimed tosylate crystalline form and that it satisfies at least one claim-defined characteristic. The accused manufacturer could challenge the reliability, reproducibility, or interpretation of the analytical test.
How do claims 2 through 5 narrow the patent?
Claims 2 through 5 add quality, composition, and administration limitations.
| Claim |
Subject matter |
Practical scope |
| 1 |
Crystalline talazoparib tosylate form |
Core solid-form claim |
| 2 |
Claim 1 form with at least about 99.5% purity |
High-purity crystalline material |
| 3 |
Claim 1 form substantially free of amorphous talazoparib or its salt or solvate |
Low-amorphous-content material |
| 4 |
Pharmaceutical composition containing the claimed form and an excipient |
Drug product containing the crystal |
| 5 |
Claim 4 composition formulated for oral administration |
Oral pharmaceutical product |
Claim 4 is commercially important because a finished capsule containing the patented crystalline form could infringe even if the patent does not claim the capsule’s exact excipient system. The composition must contain the claimed crystal, but the claim does not recite a narrow list of excipients, capsule materials, dissolution properties, or release characteristics.
Claim 5 is narrower than claim 4 because it limits the composition to oral administration. Talzenna is administered orally, making this claim particularly relevant to the marketed product.
What are the principal claim-construction issues?
Does “at least one of” broaden claim 1?
Yes. The claim language appears to define the form through alternative analytical tests rather than requiring cumulative satisfaction of all six categories. A challenger may argue that the phrase creates ambiguity if different polymorphs satisfy different individual characteristics. The patent owner would likely argue that the alternatives describe the same disclosed crystalline form and that any one recognized signature is sufficient for identification.
Are the XRPD limitations redundant?
The claim includes both d-spacing values and 2θ values. Those measurements are mathematically related through Bragg’s law, subject to the radiation wavelength and experimental conditions. The two limitations may provide overlapping evidence rather than independent structural requirements.
The d-value limitation may be more portable across instruments when the radiation source is clearly specified. The 2θ limitation may be easier to compare directly with a reference diffractogram but can be affected by instrument calibration, sample preparation, preferred orientation, and peak shifts.
Does the claim require a single polymorph?
The claim is directed to a crystalline form, not merely to a material containing some crystallinity. A product consisting primarily of a different polymorph with trace quantities of the claimed form presents a different infringement analysis from a product that is the claimed form but contains minor amorphous material.
Claim 3 specifically addresses material substantially free of amorphous talazoparib, its salts, or solvates. It does not necessarily require absolute absence. “Substantially free” would be assessed against the specification, technical evidence, and ordinary pharmaceutical interpretation.
Does the patent claim solvates?
The central form is described as unsolvated. Claim 1 includes a thermogravimetric characteristic indicative of an unsolvated material, while claim 3 excludes amorphous forms and related salt or solvate material. A distinct solvate or hydrate would have a stronger noninfringement position if its solid-state properties differ materially from the claimed form.
What is the patent’s priority date and expiration date?
The patent claims priority to an application filed on March 2, 2011. The US patent issued on May 27, 2014, as US 8,735,392 B2. Under the standard 20-year patent-term framework, the baseline expiration date is March 2, 2032, before any patent-term adjustment or patent-term extension analysis.[1]
| Event |
Date |
| Earliest identified priority date |
March 2, 2011 |
| US patent filing |
March 2, 2012 |
| US publication |
2013 |
| Patent grant |
May 27, 2014 |
| Baseline patent expiration |
March 2, 2032 |
| FDA approval of Talzenna |
October 16, 2018 |
The operative expiration date should be confirmed against the USPTO front-page patent-term calculation and the FDA Orange Book listing. Patent-term adjustment can extend the baseline date. Patent-term extension under 35 U.S.C. § 156 is a separate issue and would require a qualifying regulatory application and listed product-specific extension.
What is the FDA and Orange Book status of Talzenna?
The FDA approved Talzenna, also known as talazoparib, under NDA 211710 in 2018. The initial approval covered germline BRCA-mutated, HER2-negative locally advanced or metastatic breast cancer. FDA later approved an indication involving HRR gene-mutated metastatic castration-resistant prostate cancer in combination with enzalutamide.[2]
Talzenna is a small-molecule capsule product. It is not a biologic, so biosimilar approval under the Public Health Service Act does not apply. An authorized generic or conventional ANDA is the relevant competitive pathway.
The Orange Book is the controlling source for determining which patents the NDA holder has submitted for listing against the approved product. The key commercial question is whether US 8,735,392 is listed for the relevant Talzenna dosage forms and whether the listing remains active for the applicable NDA and indication.[3]
Regulatory protection has several distinct components:
| Protection type |
Relevance to Talzenna |
| New chemical entity exclusivity |
Delayed ANDA approval during the applicable FDA exclusivity period |
| Orphan-drug exclusivity |
May restrict approval for the same indication during the orphan period |
| Listed patents |
Can trigger Paragraph IV notice, a 30-month stay, or patent litigation |
| Method-of-use patents |
Can affect indication-specific generic labeling |
| Formulation or solid-form patents |
Can create product-specific infringement risk |
| Patent-term adjustment or extension |
Can move the final patent barrier beyond the baseline term |
FDA exclusivity and patent expiration are separate. Expiration of NCE or orphan exclusivity does not eliminate an unexpired patent. Conversely, patent expiration does not necessarily end FDA exclusivity that remains in force.
What other patents protect talazoparib?
The talazoparib estate is expected to contain several layers:
Core compound patents
Foundational patents cover the talazoparib chemical scaffold, stereochemistry, pharmaceutical salts, and related PARP-inhibitor compounds. These patents are distinct from US 8,735,392 because they focus on chemical structure and therapeutic use rather than one crystalline salt form.
Solid-form patents
US 8,735,392 is the principal patent identified by the supplied claims for the crystalline tosylate form. Solid-form patents can be commercially significant because a generic manufacturer may use the same active ingredient and still infringe if its API has the patented polymorphic form.
Pharmaceutical composition patents
Composition claims may cover tablets, capsules, excipients, particle characteristics, dosage forms, or specific formulations. US 8,735,392 includes a broad composition claim, but the supplied claims do not identify a particular excipient combination or release profile.
Method-of-use patents
Separate patents may cover treatment of breast cancer, ovarian cancer, prostate cancer, or tumors with specified genomic alterations. A method-of-use patent can remain relevant after compound or formulation patents expire, particularly where the generic label includes the patented indication.
Manufacturing and process patents
Process patents may cover crystallization conditions, solvent systems, seeding, purification, or conversion of a salt into the desired crystalline form. A process patent does not necessarily block a product made by a materially different process, but process claims can create manufacturing and supply-chain risk.
How strong is the patent estate represented by US 8,735,392?
The patent has meaningful product protection because the claimed form is tied to the commercial API rather than to an optional formulation component. Its strongest enforcement position would arise if:
- Talzenna uses the claimed crystalline tosylate form.
- A generic manufacturer uses the same salt and crystal form.
- The generic product is made with a purity and solid-state profile matching the claim.
- The patent is listed in the Orange Book for the relevant NDA.
- The accused product satisfies at least one of the analytical alternatives in claim 1.
The main design-around opportunities are:
- Use of a different salt.
- Use of talazoparib free base, if pharmaceutically and operationally viable.
- Use of a distinct polymorph.
- Use of a hydrate or solvate with materially different properties.
- Use of an amorphous dispersion that does not contain the claimed crystalline form.
- Selection of a different manufacturing route that avoids separate process claims.
The most difficult design-around is likely a different solid form that maintains acceptable stability, dissolution, bioavailability, manufacturability, and storage performance. A legal noninfringement position is commercially weak if the alternative form creates unacceptable regulatory or product-quality risks.
What generic entry risks exist for Talzenna?
A generic applicant could pursue several strategies:
Paragraph III certification
The applicant accepts the listed patents and seeks approval after their expiration. For US 8,735,392, the baseline date would be March 2, 2032, subject to any adjustment.
Paragraph IV certification
The applicant alleges that the patent is invalid, unenforceable, or not infringed. The patent owner may file suit within 45 days of receiving notice, potentially triggering a 30-month stay of ANDA approval under the Hatch-Waxman framework.[4]
Section viii statement
The applicant may remove a patented method of use from its labeling if the relevant patent covers only an indication and the product can be marketed for non-patented uses. This strategy is less useful against a product-by-process, composition, or solid-form patent covering the API in the approved product.
Formulation or polymorph design-around
A generic company may develop an alternative crystal, salt, or amorphous form. FDA approval would still require pharmaceutical equivalence, bioequivalence, quality control, and adequate manufacturing support.
No biosimilar challenge is relevant because talazoparib is a conventional small molecule.
Which companies are challenging Talzenna patents?
The supplied claim set does not identify a Paragraph IV challenger, ANDA applicant, district-court case, or settlement agreement. A definitive company-by-company challenge analysis requires matching the current Orange Book listing to FDA Paragraph IV notices and federal litigation records.
The relevant records are:
- FDA Orange Book patent listings.
- FDA Paragraph IV notice information, where publicly available.
- PACER and district-court dockets.
- ANDA litigation complaints and consent judgments.
- SEC filings by Pfizer and generic applicants.
- Settlement agreements filed under the Medicare Modernization Act.
A patent landscape should not treat the existence of an unexpired patent as proof that litigation is pending. Patent status, Orange Book listing status, ANDA certification status, and litigation status are separate data points.
What is the commercial exposure from US 8,735,392?
Talzenna revenue is exposed to the combined patent estate, not to US 8,735,392 alone. The commercial effect of this patent depends on whether the generic applicant can avoid the claimed crystalline form and whether other compound, use, formulation, or process patents remain enforceable.
| Risk factor |
Effect on generic entry |
| Core compound patent remains unexpired |
May block use of talazoparib itself |
| Crystal-form patent remains unexpired |
May block the commercial API form |
| Method-of-use patents remain listed |
May delay or restrict indication approval |
| Alternative polymorph is feasible |
Reduces exposure to US 8,735,392 |
| Alternative polymorph has poor stability |
Increases practical value of the patent |
| Paragraph IV litigation is filed |
May create a 30-month FDA stay |
| Settlement permits an agreed entry date |
Converts litigation risk into a timed launch scenario |
Key Takeaways
- US 8,735,392 protects a specific crystalline tosylate form of talazoparib.
- Claim 1 uses alternative analytical limitations, including XRPD, solid-state NMR, DSC, TGA, and dynamic vapor sorption.
- Claims 2 and 3 add purity and amorphous-material limitations.
- Claims 4 and 5 extend the protection to pharmaceutical compositions and oral products.
- The patent does not broadly claim all talazoparib, all salts, all polymorphs, or all therapeutic uses.
- The baseline expiration date is March 2, 2032, subject to USPTO patent-term adjustment.
- Talzenna is a small-molecule drug; biosimilar competition does not apply.
- Generic entry depends on Orange Book listings, Paragraph III or IV certifications, litigation, settlements, and successful solid-form design-around.
- A distinct salt, polymorph, solvate, or amorphous form may provide a noninfringing route, but regulatory and manufacturing feasibility remain critical.
- The patent’s commercial strength is highest if Talzenna and prospective ANDA products use the claimed unsolvated crystalline tosylate form.
FAQs About US Patent 8,735,392 and Talazoparib
Is US 8,735,392 a patent on Talzenna’s active ingredient?
It is a patent on a specific crystalline tosylate salt form of talazoparib. Broader protection for the talazoparib molecule may arise from separate compound patents.
Can a generic use talazoparib without infringing US 8,735,392?
Potentially. A generic may avoid this patent by using a different salt, polymorph, solvate, or amorphous form, provided the alternative is pharmaceutically suitable and does not infringe other patents.
Does the patent cover Talzenna capsules specifically?
Claim 4 covers a pharmaceutical composition containing the claimed crystal and an excipient. Claim 5 covers an oral version. The claims do not require a particular capsule shell, excipient mixture, or strength.
What test is most important for proving infringement?
No single test is necessarily controlling because claim 1 recites “at least one of” several analytical characteristics. XRPD is likely to be central, with solid-state NMR and thermal analysis used to confirm identity and distinguish related forms.
Will patent expiration automatically permit generic Talzenna approval?
No. Generic approval may also depend on other unexpired listed patents, FDA exclusivity, litigation stays, method-of-use restrictions, and the applicant’s ability to satisfy ANDA requirements.
References
- United States Patent and Trademark Office. (2014). US Patent No. 8,735,392 B2: Crystalline form of (8S,9R)-5-fluoro-8-(4-fluorophenyl)-9-(1-methyl-1H-1,2,4-triazol-5-yl)-8,9-dihydro-2H-pyrido[4,3,2-de]phthalazin-3(7H)-one tosylate salt.
- U.S. Food and Drug Administration. (2023). Talzenna prescribing information. Pfizer Laboratories.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. §§ 355, 355(j); 35 U.S.C. §§ 154, 156.
