Use of patent term extensions to restore regulatory time for medical devices in the United States

ABSTRACT

Background

Medical devices can seek patent term extensions (PTEs), which extend market exclusivity to compensate for delays related to clinical trials and regulatory review. Pharmaceutical companies commonly use PTEs, but their use by medical device companies has not been clear.

Research Design and Methods

We examined the use of PTEs by medical device companies between 1984 and 2024 using a database published in the Federal Register and a list published by the Patent and Trademark Office.

Results

Only 178 medical device submissions were linked to a PTE application. They were mostly concentrated in 116 product codes associated with 15 medical specialties; nearly half were associated with cardiovascular devices. Numbers increased significantly in the past decade. Successful applications restored 987 days on average.

Conclusions

The patent restoration opportunity appears underutilized. It is unclear whether some companies do not recognize the opportunity it promises, or whether it does not meet their needs. Different business features and marketing strategies in device versus pharmaceutical industries may decrease the usefulness of the PTE program for these types of medical products. However, the finding that a small subset of manufacturers operating in competitive markets adopted patent extension strategies more commonly suggests a significant competitive advantage when competition increases.

KEYWORDS:

• The drug price competition and patent term restoration act
• market exclusivity
• patent
• patent term extension
• patent term restoration
• PTE
• PMA

1. Introduction

Novel products that are marketed in the US can be protected by patents that typically shield the product from competition for 20 years [1,2]. For a medical product, however, the duration of this exclusivity can be eroded if the product cannot enter the market without extensive testing and regulatory review to guarantee its safety and efficacy. To compensate for this situation, the Drug Price Competition and Patent Term Restoration Act (DPCPTRA; also known as the Hatch-Waxman Amendments) of 1984 (Pub. L. No. 98–417) [3], along with the Generic Animal Drug and Patent Term Restoration Act of 1988 (Pub. L. No. 100–670) [4] introduced a program by which a patent may be extended for up to 5 years and not exceeding 14 years beyond regulatory approval if the patented item must undergo regulatory review by the FDA before entering the market [5–8]. These laws have been interpreted broadly to include medical devices, biologics, food and color additives, as well as human and animal drugs [9]. Under these rules, the patent extension period will be calculated as the sum of the length of the regulatory review period and half the length of the allowable clinical trial period. A manufacturer seeking a Patent Term Extension (PTE) under 35 U.S.C. § 156 [10] must submit the PTE application to the United States Patent and Trademark Office (USPTO) within 60 days of receiving FDA approval for the device. The application should specify the associated patent for which an extension is sought. The USPTO will verify the FDA authorization and coordinate with the FDA to obtain regulatory dates and periods related to the approval. Once the information has been received, the FDA will provide a response letter to the USPTO that includes details about the identified patent, FDA authorization information, and pertinent regulatory timeframes. Subsequently, this information will be made public through publication in the Federal Register (35 U.S.C. § 156(2)(A)) [10].

Patent term extension has been widely embraced by pharmaceutical and biotechnology companies to capitalize on competitive advantages and to extend market exclusivity after the product is launched [11–14]. This PTE practice has been adopted and stipulated into laws around the world, including countries such as Australia, Brazil, India, Japan, and Europe [15–19]. The extension allows them to maintain a monopoly and thus sell the product at a higher price than would be possible if the drug were off patent. Medical device companies are also eligible for the same opportunity. However, anecdotal evidence suggests that medical device companies are less likely to seek market exclusivity than companies in the pharmaceutical and biotechnology sectors [20,21]. This study examines systematically the use of patent extension across different medical device types. It confirms that adoption of the program is relatively low. However, it also identifies that the rates are much higher for certain types of medical products than for others.

2. Methods

2.1. Data compilation and determination

We identified manufacturers and their associated devices that had filed for Patent Term Extension (PTE) through information sourced from the USPTO and the Federal Register websites. In the USPTO website, we used the latest available data, published in November 2023 [22]. From these data, we compiled two lists. One detailed PTE application filed in the last five years (constrained because the PTO has only published data for this period) and the other enumerated patents that were successfully extended. The Federal Register website was utilized to download FDA response letters pertaining to PTE. As of 8 February 2024, the FDA database contained a total of 50,051 approvals with an approval date between 1 January 1984, and 31 December 2023, including 1251 Premarket Approvals (PMAs), 101 Humanitarian Device Exemptions (HDEs), and thousands of Supplements, mostly directed at changes in manufacturing processes, design components, or labeling.

The compiled lists were verified against both the FDA and USPTO databases so that unspecified records, including several entries in the USPTO lists, could be removed. Specifically, both ‘Vending Machine’ and ‘Vending Machine and Computer Assembly’ were excluded because regulatory information was absent, rendering them ineligible for Patent Term Extension (PTE) as determined by the USPTO. In cases of a conflict between the ‘medical specialty’ and the ‘review code,’ the analysis prioritized information from the medical specialty. The terms, ‘medical specialty’ or ‘advisory committee,’ are used in different databases and are used interchangeably in this study.

Some devices were associated with not only an original regulatory application but also one or more supplements updating the marketing approval with modifications of the device or its labeling; only 18 of these were associated with a PTE. The FDA database does not always include regulatory information for the correct supplement, so we analyzed the data available in the immediately subsequent supplement. The application filing dates and FDA approval dates were thus not current, but other information relating to review panel and applicant information was consistent with the missing application.

To examine the association between the numbers of single PTE applications and time, the 40-year period since the inception of the DPCPTRA was divided into four 10-year epochs. A Fisher – Freeman – Halton exact test (n x m table) was conducted using IBM SPSS Statistics [23] (Version 28, IBM, New York, NY, U.S.A.). The p-values $\le$0.05 were considered significant. Durations of PTEs were compared to those of drugs and biologics by dividing the data into four 10-year epochs and exercising Levene’s Test of Equality of Error Variances between Means.

2.2. Competitiveness analysis

Product codes are unique identifiers assigned to specific types of medical devices categorized by intended use, technological characteristics, and other characteristics. To assess competitiveness, we curated company information associated with PTE filings for each product code. The product codes were categorized as follows: 1) Fierce Competition was designated when the product code involved multiple companies, and the ratio of PTEs to PTE filing companies exceeded 1; 2) Strong Competition when the product code involved multiple companies and the ratio of PTE to PTE filing companies equaled 1; 3) No Competition when the product code involved multiple companies but only one of them filed one or more PTE applications; and 4) No Competition/Sole Company when the product code was associated with only one company.

3. Results

3.1. Characteristics of PTE applications

We identified 178 regulatory submissions linked to a PTE application since the inception of the DPCPTRA in 1984. They included 153 PMAs, 18 PMA supplements and 4 HDEs. In addition, three PTE applications were associated with products in Class II, including 2 De Novo applications (for devices that were unclassified at the time of submission and were requesting Class II designation), and 1 510(k) application (for devices in Class II with a predicate). Cardiovascular codes comprised the largest subset, accounting for 42%, and were followed by Orthopedic (13%) and Ophthalmic (10%) codes (Table 1). Further details of product information, including product types, are readily available in the table in the Supplemental Section. More recent sampling periods show a notable increase in the numbers of PTEs for Gastroenterology & Urology (Table 1). The 178 submissions were distributed across 116 product codes associated with 15 medical specialties (see Supplement for detailed data). About half of the product codes (49%) had only one instance in which a PTE was sought. Another 13.8% of product codes had two such PTEs and 22% had 3 to 5 PTEs. Additionally, 15.6% of product codes had 8 PTE applications, as detailed in the Supplemental material.

Table 1. Classification of PTE applications by medical specialty.

Time Period Medical Specialty	I (84–93)	II (94–03)	III (04–13)	IV (14–23)	Count	%
Cardiovascular	9	13	16	37	75	42.1%
Orthopedic	2	7	4	10	23	12.9%
Ophthalmic	2	7	3	6	18	10.1%
Gastroenterology & Urology	1	1	1	9	12	6.7%
Neurology		2	3	7	12	6.7%
General & Plastic Surgery	3	4	3	1	11	6.2%
Anesthesiology			4	3	7	3.9%
Obstetrics/Gynecology	1	3		1	5	2.8%
Radiology	1	2		1	4	2.2%
Hematology				3	3	1.7%
Clinical Chemistry			1	1	2	1.1%
Pathology			1	1	2	1.1%
General Hospital	1				1	0.6%
Dental			1		1	0.6%
Ear, Nose, & Throat				1	1	0.6%
Physical Medicine				1	1	0.6%
Immunology					0	0.0%
Microbiology					0	0.0%
Clinical Toxicology					0	0.0%
Total	20	39	37	82	178	100%

3.2. PTE approvals and characteristics

To date, of 178 PTE submissions, 125 successfully obtained a PTE; most others are still in process. The large majority were associated with PMA applications but 3 HDE applications (H010002/S001, H070003; H110002) and 6 PMA supplements (P880038/S013; P910030/S005; P930014/S009; P110019/S025; P000025/S084; P050006/S071) were included. On average, the period of the extension was 987 days, comparable to that of drugs with 1063 days and biologics with 1057 days (Table 2).

Table 2. Average PTE durations for different product types.

Product Type*	Mean ± S.D.^†	N	%	N of FDA Approvals
BLA	1057.0 ± 523.4	140	14.1%	746^‡
Food Additive	1132.0 ± 487.5	11	1.1%
NADA	1101.5 ± 468.5	49	4.9%
NDA	1063.4 ± 518.3	670	67.3%	1040^‡
PMA	987.2 ± 560.7	125	12.6%	1251^§
Total	1055.6 ± 521.6	995	100.0%

*Abbreviations for different product types. BLA: Biologics License Application; NADA: New Animal Drug Application; NDA: New Drug Application; PMA: Premarket Approval.

^†S.D. = Standard Deviation.

^‡CDER NME and New Biologic Approvals 1985–2023 and Biologic Approvals in the Purple Book 2023 December Editon.

^§The number of PMAs whose decision date is between January 1, 1984, through December 31, 2023.

^¶ANOVA analysis conducted on the granted period of extension (in days) revealed no statistically significant differences among various product types with respect to the time restored (Levene’s Test of Equality of Error Variances between means: 1.774, Sig. 0.132, p ≤ 0.05).

3.3. Time trend for PTE submissions

Of 178 PTE applications submitted over the last 40 years, 20 were from 1984 through 1993, 39 from 1994 through 2003, 37 from 2004 through 2013, and 82 from 2014 through 2023. Product codes with a single PTE application dominated all four periods (Table 3). A Fisher-Freeman-Halton Exact Test was conducted to determine if the rate of single PTE applications changed over time (Table 4). It gave an estimate of 17.989, p = 0.028, indicating a significant increase of single PTE applications in the recent decade.

Table 3. Changes in rates of PTEs over time.

PMA Decision Year in 4 Periods	Group	Total Number of PTEs in 4 Groups				Count
		A (8)*	B (3–4)	C (2)	D (1)**
I (84–93)	Count	4	2	2	12	20
	% within PMA Decision Year	20.0%	10.0%	10.0%	60.0%	100.0%
	% within PTE Group	16.7%	5.3%	7.1%	13.6%	11.2%
	% of Total	2.2%	1.1%	1.1%	6.7%	11.2%
II (94–03)	Count	4	16	2	17	39
	% within PMA Decision Year	10.3%	41.0%	5.1%	43.6%	100.0%
	% within PTE Group	16.7%	42.1%	7.1%	19.3%	21.9%
	% of Total	2.2%	9.0%	1.1%	9.6%	21.9%
III (04–13)	Count	8	7	6	16	37
	% within PMA Decision Year	21.6%	18.9%	16.2%	43.2%	100.0%
	% within PTE Group	33.3%	18.4%	21.4%	18.2%	20.8%
	% of Total	4.5%	3.9%	3.4%	9.0%	20.8%
IV (14–23)	Count	8	13	18	43	82
	% within PMA Decision Year	9.8%	15.9%	22.0%	52.4%	100.0%
	% within PTE Group	33.3%	34.2%	64.3%	48.9%	46.1%
	% of Total	4.5%	7.3%	10.1%	24.2%	46.1%
	Total	24	38	28	88	178
	% within PMA Decision Year	13.5%	21.3%	15.7%	49.4%	100.0%
	% within PTE Group	100.0%	100.0%	100.0%	100.0%	100.0%
	% of Total	13.5%	21.3%	15.7%	49.4%	100.0%

Individual PTE applications increased significantly in recent time periods. Group A: Products with a total of 8 PTE applications with the same product code; Group B: Products with a total of 3 to 5 PTE applications with the same product code; Group C: Products with a total of 2 PTE applications with the same product code; Group D: Products with only 1 PTE application associated with the product code.

Table 4. Chi-square tests.

	Value	df	Asymptotic Significance (2-sided)	Exact Sig. (2-sided)
Likelihood Ratio	19.003	9	0.025	0.036
Fisher-Freeman-Halton Exact Test	17.989			0.028
N of Valid Cases	178

3.4. Competitiveness analysis

To assess competitiveness, we curated company information associated with PTE filings for each product code. For example, in the case of a cardiovascular device product code LWS with 27 PMAs, 8 PTE applications were identified which were filed by 4 companies, resulting in a PTE to PTE companies ratio of 2.0 (1st row, Table 6). In this way, PTE applications from the various medical specialties were broken down according to the four levels of competitiveness of the product code (Table 5), with detailed information shown in Table 6.

Table 5. Competitiveness analysis identified four primary types of product codes based on PTE filing conditions.

Medical Specialty	Fierce Competition	Strong Competition	No Competition	Sole Company	Count
Cardiovascular	5	7	11	15	38
Ophthalmic	1	2	9	1	13
General & Plastic Surgery	1	1	2	1	5
Orthopedic		4	4	8	16
Gastroenterology/Urology		1	4	6	11
Obstetrics/Gynecology		1	3		4
Neurology		1	1	6	8
Anesthesiology			2	5	7
Radiology			2	2	4
Clinical Chemistry			1	1	2
Dental			1		1
Ear, Nose & Throat			1		1
General Hospital			1		1
Pathology				2	2
Hematology				2	2
Physical Medicine				1	1
Total	7	17	42	50	116
%	6.0%	14.7%	36.2%	43.1%	100.0%

Table 6. Examples of product codes categorized into one of the four competition categories.

Medical Specialty	Medical Specialty	Product Code	I (84–93)	II (94–03)	III (04–13)	IV (14–23)	PTE Count	PMA Count	% PMA Seeking for PTE	PMA & Supplements Count	PTE Company Count	PTE/PTE Company	PMA Company Count	Competition Level
Cardiovascular	CV	LWS	4	3	1		8	27	30%	2539	4	2.0	7	Fierce Competition
Cardiovascular	CV	NIQ		1	6	1	8	16	50%	1307	4	2.0	8	Fierce Competition
Cardiovascular	CV	NPT			1	7	8	7	114%	574	3	2.7	4	Fierce Competition
Cardiovascular	CV	LWQ	1	2			3	12	25%	367	3	1.0	8	Strong Competition
General & Plastic Surgery	SU	LMH	1	1	2	1	5	17	29%	882	4	1.3	10	Fierce Competition
Cardiovascular	CV	MAF		4			4	24	17%	860	3	1.3	10	Fierce Competition
General & Plastic Surgery	SU	MGR		3			3	5	60%	162	3	1.0	4	Strong Competition
Orthopedic	OR	MAX		3			3	6	50%	58	3	1.0	6	Strong Competition
Ophthalmic	OP	HQL		2		1	3	67	4%	1577	2	1.5	23	Fierce Competition
Neurology	NE	LGW		1		2	3	8	38%	1165	3	1.0	8	Strong Competition
Cardiovascular	CV	MIH			3	1	4	21	19%	935	4	1.0	9	Strong Competition
Orthopedic	OR	MJO			2	2	4	13	31%	197	4	1.0	9	Strong Competition
Cardiovascular	CV	LWR				3	3	13	23%	506	2	1.5	5	Fierce Competition
Neurology	NE	NHL				3	3	2	150%	62	1	3.0	2	No Competition
Cardiovascular	CV	DXY	2				2	20	10%	632	2	1.0	8	Strong Competition
Obstetrics/Gynecology	OB	MNB		1		1	2	9	22%	269	2	1.0	7	Strong Competition
Orthopedic	OR	MOZ		1		1	2	14	14%	287	2	1.0	9	Strong Competition
Orthopedic	OR	NQO			2		2	3	67%	65	2	1.0	3	Strong Competition
Gastroenterology/Urology	GU	LNM			1	1	2	9	22%	257	2	1.0	8	Strong Competition
Ophthalmic	OP	OGO			1	1	2	5	40%	68	1	2.0	3	No Competition
Cardiovascular	CV	OAE			1	1	2	10	20%	289	2	1.0	6	Strong Competition
Cardiovascular	CV	NKM			1	1	2	2	100%	74	2	1.0	2	Strong Competition
Cardiovascular	CV	NIP				2	2	12	17%	487	2	1.0	9	Strong Competition
Ophthalmic	OP	LQE				2	2	3	67%	27	2	1.0	3	Strong Competition
Hematology	HE	PJF				2	2	2	100%	73	1	2.0	1	Sole Company
Cardiovascular	CV	PNJ				2	2	2	100%	184	2	1.0	2	Strong Competition
Ophthalmic	OP	POE				2	2	4	50%	13	2	1.0	3	Strong Competition
Cardiovascular	CV	QCT				2	2	2	100%	14	1	2.0	1	Sole Company
Gastroenterology/Urology	GU	LNR	1				1	1	100%	105	1	1.0	1	Sole Company
General & Plastic Surgery	SU	GAS	1				1	6	17%	50	1	1.0	4	No Competition
General & Plastic Surgery	SU	GAM	1				1	3	33%	29	1	1.0	2	No Competition

Five of the 7 product codes identified as having fierce competition were codes for cardiovascular devices, including LWS: Implantable Cardioverter Defibrillator; NIQ: Coronary Drug-Eluting Stent; NPT: Aortic Valve, Prosthesis, Percutaneously Delivered; MAF of Stent, Coronary; and LWR: Heart-Valve, Non-Allograft Tissue (Table 6). The remaining two product codes were LMH (General & Plastic Surgery): Implant, Dermal, For Aesthetic Use, and HQL (Ophthalmic): Intraocular Lens (Table 6).

4. Discussion

PTE is actively pursued by pharmaceutical companies in the U.S. and widely utilized worldwide. This study aimed to uncover the reasons behind the low level of PTE utilization and included all PTE applications for analysis, including a class II device reviewed under 510(k) process. A 510(k) device is not eligible for patent term extension under 35 U.S.C. 156, which applies to class III devices reviewed under section 515 of the Food, Drug, and Cosmetics Act (FFDCA), but does not mention section 510K of the FFDCA. For this case, and other class III devices that failed to receive a PTE certificate, further research is warranted, but beyond the scope of this study.

4.1. Current status of PTE use for medical devices

Results presented here show a striking difference between the use of PTEs by companies that market medical devices compared to those that market drugs [24–26]. To some degree, this might be explained because medical devices vary widely in their risk profiles. Devices with relatively low risk, and fall into FDA’s Class I and II, typically have shorter development and review periods and seldom require clinical trials. Further, they usually have predicates already on the market and do not base their market strategy on having patent protection. Thus, patent extensions are most appropriate for Class III medical devices that typically have a lengthy development and regulatory review periods associated with PMA, PMA supplement or HDE submissions [20,21]. Nonetheless, even for Class III devices, the PTE opportunity seems undersubscribed. Class III devices are distributed across 529 product codes (475 for PMA and 54 for HDE, FDA Product Code database accessed on 9 February 2024) and have made 1251 submissions (PMAs and HDEs whose decision date is between 1 January 1984, through 31 December 2023). Nonetheless, only 116 product codes and 125 PMAs were found in which at least one device participated in the PTE program.

4.2. Trends for PTE filing

This study also reveals a notable increase in PTE applications for medical devices over the past decade, suggesting two interesting trends. First, there is a substantial rise in the number of supplements seeking extensions. Supplements typically are needed when the original product has been changed to modify or add functionality [27]; most are for changes that would not qualify for PTEs. However, a minority are for line extensions or new indications that would require a clinical trial and for which the PTE might be justified. In these cases, some manufacturers are actively pursuing patent safeguards for incremental advancements as well as novel products [28,29].

Second, an increase was seen in the number of PTE applications linked to a new product code. A new product code signifies the entry of a previously unrecognized category of innovative products that are distinct from existing ones [30]. In this study, some of the product codes which had only one or two PTEs also had only a few PMAs overall, a pattern typically seen shortly after the introduction of a new product code. Pressures to protect these innovative products from competition seem compelling. Over the past decade, the testing and regulatory requirements for high-risk, Class III medical devices have increased, so that millions of dollars must be invested for many years to bring such products to market [31]. A PTE offers to opportunity to recoup this investment over a longer marketing period during which the device is protected from competition. The increased use of these PTEs may underscore the strategic approach that companies are now taking to identify ways in which they can gain market advantage for certain product types [32]. Data also suggest that PTE filing is heightened for products entering highly competitive markets [28]. In the latter situations, it is not surprising that patent term extension might be seen as providing an economic advantage to discourage and delay competition.

4.3. Competitiveness analysis

What is not clear is whether the modest use of the PTE program occurs because many medical device companies do not understand its availability or usefulness, or because the PTE system is viewed as ‘more trouble than it is worth’ for most types of products. The use of the PTE system by companies in strongly competitive sectors suggests that at least some of these manufacturers are not only familiar with the PTE program but are also enthusiastic about to using it to protect their products [33–36]. If the goal of PTE program is to foster the introduction of innovative medical devices, thought should be given to understanding the views and experiences of industry stakeholders regarding its usefulness. This will best be assessed by a different type of study in which industry stakeholders are consulted about their needs and concerns. Otherwise, it is not clear whether more education regarding the use and advantages of the PTE program would increase its use as a mechanism to encourage investments in novel medical devices.

This study identified a low level of PTE utilization even by device companies making Class III devices that have a long developmental and regulatory path. We acknowledge that a lack of familiarity with the PTE program may be responsible for its low use. However, the fact that manufacturers in competitive markets are adopting patent extension strategies more commonly may suggest that the PTE program [30], with its inherent costs to obtain and manage, is considered useful only by a small subset of companies in which it is seen to offer significant competitive advantage.

4.4. Limitations and delimitations

This study was limited by the data availability. We incorporated PTE applications published by the USPTO and in the Federal Register before 1 January 2024 but could not capture data related to some regulatory submissions made in and before 2023, because some applications might not have been posted by the regulatory agencies at the time of the analysis. Therefore, for the most recent two periods, from 2014 to 2023, the numbers are likely to be underestimated. Challenges were also identified in determining the patent landscape for PMA supplements, many of which were missing in the FDA databases.

5. Conclusions

This study aimed to uncover the reasons behind the low level of PTE utilization. Our findings indicated that the use of the PTE is lower for medical devices than drugs. However, it is increasing over time and is primarily though not exclusively associated with a small number of product codes with PMAs for products in new or competitive markets. A lack of awareness about the PTE program may be a potential factor in the uneven adoption, but manufacturers also appear to be increasing their use of patent extension strategies when they align with their marketing approaches.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Author contributions

CBK: Study design, data analysis, manuscript drafting, review, and critique. FJR: Data interpretation, manuscript drafting, review, and critique.

Acknowledgments

The authors thank Dr. Gerald Loeb for his helpful discussions of the data and manuscript.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/17434440.2024.2363298.

Additional information

Funding

This paper was not funded.