United States General Accounting Office

GAO Report to the Chairman, Subcommittee

on Oversight and Investigations,

Committee on Commerce, House of

Representatives

October 1995 MEDICAL DEVICES

FDA Review Time

GAO/PEMD-96-2

GAO United States

General Accounting Office

Washington, D.C. 20548

Program Evaluation and

Methodology Division

B-261822 

October 30, 1995

The Honorable Joe Barton

Chairman, Subcommittee on Oversight

 and Investigations

Committee on Commerce

House of Representatives

Dear Mr. Chairman:

As you know, the Food and Drug Administration (FDA) regulates the

manufacture and marketing of medical devices in this country. Some

criticism has been expressed that FDA’s review of medical devices is

excessively lengthy and can impose inordinate delays upon the

introduction of new devices into the market. At your request, we examined

FDA’s review time and how it has changed from fiscal year 1989 to May 18,

1995. We analyzed data provided by FDA on applications to market new

devices or to begin clinical research on unapproved devices. We briefed

your staff on the findings of our preliminary analysis in June 1995, and we

have since requested and received comments on these findings from FDA.

Background

Types of FDA Reviews Medical devices can range in complexity from a simple tongue depressor

to a sophisticated CT (computed tomography) x-ray system. Most of the

devices reach the market through FDA’s premarket notification (or 510(k))

review process.1

 Under its 510(k) authority, FDA may determine that a

device is substantially equivalent to a device already on the market and

therefore not likely to pose a significant increase in risk to public safety.

When evaluating 510(k) applications, FDA makes a determination regarding

whether the new device is as safe and effective as a legally marketed

predicate device. Performance data (bench, animal, or clinical) are

required in most 510(k) applications, but clinical data are needed in less

than 10 percent of applications.2

1

Premarket notification is commonly called 510(k) in reference to section 510(k) of the Federal Food,

Drug, and Cosmetic Act.

2

510(k) applications must contain a description of the device, description of the predicate device with

which it is substantially equivalent, proposed labeling, intended use, and directions for use.

Page 1 GAO/PEMD-96-2 FDA Medical Device Review Time
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An alternative mode of entry into the market is through the premarket

approval (PMA) process. PMA review is more stringent and typically longer

than 510(k) review. For PMAs, FDA determines the safety and effectiveness

of the device based on information provided by the applicant. Nonclinical

data are included as appropriate.3

 However the answers to the

fundamental questions of safety and effectiveness are determined from

data derived from clinical trials.4

FDA also regulates research conducted to determine the safety and

effectiveness of unapproved devices. FDA approval is required only for

“significant risk” devices.5

 Applicants submit applications for such devices

to obtain an investigational device exemption (IDE) from regulatory

requirements and approval to conduct clinical research. For an IDE, unlike

PMAs and 510(k)s, it is the proposed clinical study that is being

assessed—not just the device.

Modification of Cleared or

Approved Applications for

Devices

Modifications of medical devices, including any expansion of their labeled

uses, are also subject to FDA regulation. Applications to modify a device

that entered the market through a PMA are generally linked to the original

PMA application and are called PMA supplements. In contrast, modifications

to a 510(k) device are submitted as new 510(k) applications. References

may be made to previous 510(k) applications.

Measuring the Length of

FDA Reviews

FDA uses several measures of duration to report the amount of time spent

reviewing applications. In this letter, we use only three of those measures.

The first is simply the time that elapses between FDA’s receipt of an

application and its final decision on it (total elapsed time). The second

measure is the time that FDA has the application under its review process

(FDA time). This includes both the time the application is under active

review and the time it is in the FDA review queue. The amount of time FDA’s

3

Nonclinical data may include microbiological, toxicological, immunological, biocompatibility, shelf

life, animal, engineering (stress, wear, fatigue) data.

4

For PMAs, information on the device and its components, the manufacturing process, labeling that

includes its intended use and directions for use as well as clinical and nonclinical studies are included

in the submission.

5

A “significant risk” device is one that is intended as an implant, used in supporting or sustaining

human life, of substantial importance in diagnosing, curing, mitigating or treating disease, or otherwise

prevents impairment of human health, and presents a potential for serious risks to the health, safety,

or welfare of a subject (21 C.F.R. 812.3(m)). For a nonsignificant risk device only Institutional Review

Board approval is required.

Page 2 GAO/PEMD-96-2 FDA Medical Device Review Time
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review process has been suspended, waiting for additional information

from the applicant, is our third measure (non-FDA time).

Our measures of review time are not intended to be used to assess the

agency’s compliance with time limits for review established under the

Federal Food, Drug, and Cosmetic Act (the act).6

 The time limits for PMA,

510(k), and IDE applications are 180, 90, and 30 days, respectively. FDA

regulations allow for both the suspension and resetting of the FDA review

clock under certain circumstances.7

How review time is calculated differs for 510(k)s and PMAs. If a PMA

application is incomplete, depending on the extent of the deficiencies, FDA

may place the application on hold and request further information. When

the application is placed on hold, the FDA review clock is stopped until the

agency receives the additional information. With minor deficiencies, the

FDA review clock resumes running upon receipt of the information. With

major deficiencies, FDA resets the FDA clock to zero upon receipt of the

information. In this situation, all previously accrued FDA time is

disregarded. (The resetting of the FDA clock can also be triggered by the

applicant’s submission of unsolicited supplementary information.) The

amount of time that accrues while the agency is waiting for the additional

information constitutes non-FDA time. For 510(k)s, the FDA clock is reset

upon receipt of a response to either major or minor deficiencies.

For this report, we define FDA time as the total amount of time that the

application is under FDA’s review process. That is, our measure of FDA time

does not include the time that elapses during any suspension, but does

include time that elapsed before the resetting of the FDA clock. The total

amount of time that accrues while the agency is waiting for additional

information constitutes non-FDA time. (The sum of FDA and non-FDA time is

our first measure of duration—total elapsed time.)

Classes and Tiers of

Medical Devices

The act establishes three classes of medical devices, each with an

increasing level of regulation to ensure safety and effectiveness. The least

regulated, class I devices, are subject to compliance with general controls.

Approximately 40 percent of the different types of medical devices fall into

6

FDA, as indicated by its own reports, has sometimes failed to meet these time limits. For example, in

1994, only 45 percent of its 510(k) reviews were completed within 90 days.

7

See 21 C.F.R. 814.37 and 814.40 for PMAs and 21 C.F.R. 807.87(k) for 510(k)s. The review of IDE

applications is not subject to the resetting of the FDA review clock; investigations for which IDE

applications are submitted may begin within 30 days of application receipt if FDA fails to act (see 21

C.F.R. 812.30).

Page 3 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

class I. At the other extreme is premarket approval for class III devices,

which constitute about 12 percent of the different types of medical

devices. Of the remainder, a little over 40 percent are class II devices, and

about 3 percent are as yet unclassified.8

In May 1994, FDA implemented a three-tier system to manage its review

workload. Classified medical devices are assigned to one of three tiers

according to an assessment of the risk posed by the device and its

complexity. Tier 3 devices are considered the riskiest and require intensive

review of the science (including clinical data) and labeling. Review of the

least risky devices, tier 1, entails a “focused labeling review” of the

intended use. In addition to the three tiers is a group of class I devices that

pose little or no risk and were exempted from the premarket notification

(510(k)) requirements of the act.9

Under the class and tier systems, approximately 20 percent of the different

types of medical devices are exempted from premarket notification.10 A

little over half of all the different types of medical devices are classified as

tier 2 devices. Tiers 1 and 3 constitute 14 and 12 percent of the different

types of medical devices, respectively.11

Results in Brief Review times and trends for medical device applications varied widely

over the period beginning October 1, 1988, through May 18, 1995. For

510(k) applications submitted in a given fiscal year, the review time

remained stable over the 3 years from 1989 to 1991, then rose sharply in

1992 and 1993 before dropping in 1994. For 1994, the median was 152 days.

The mean time to a decision was higher, at 166 days, and this mean will

8

General controls for class I devices include registering device manufacturing facilities, providing FDA

with regularly updated lists of marketed devices, complying with good manufacturing practices (as

established by FDA), and maintaining records and filing reports of device-related injuries and

malfunctions. The Safe Medical Devices Act of 1990 revised the requirements for class II devices,

subjecting them to both general and special controls. Special controls include performance standards,

postmarket surveillance, patient registries, and other controls as deemed necessary. Class III devices

require clinical data to demonstrate safety and effectiveness.

9

These exempted devices remain subject to other requirements of the act. (See footnote 8.)

10Our 20-percent figure was determined by obtaining a frequency distribution by tiers of the

information FDA provided.

11Medical devices have both a class and a tier designation associated with them. Although tiers were

not implemented until 1994, for this report, we have applied the tier classification retrospectively to

our data to examine review time.

Page 4 GAO/PEMD-96-2 FDA Medical Device Review Time
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continue to grow as the remaining open cases (13 percent) are

completed.12

The review time trend for original PMAs was less clear, in part because a

large proportion of the applications have yet to be completed. Open cases

ranged from 4 percent of 1989 to 81 percent of 1994 applications. More

than 40 percent of the 1992 and 1993 applications were still open. The

median for 1994 was undetermined as less than 50 percent of the

applications were completed. For 1993, the median review time was 804

days.

The review time for PMA supplements, however, fluctuated slightly in the

first 3 years, before peaking in 1992 and declining thereafter. The median

for 1994 was 193 days as opposed to a mean of 162 days. Again, the mean

will increase when the remaining open cases (21 percent) are closed.

Not all the time that elapsed between an application’s submission and its

final determination was spent under FDA’s review process. In many

instances, FDA had to wait for additional information. This non-FDA time

comprised about one-fifth of total elapsed review time for 510(k)s. It

constituted about one-fourth of total elapsed review time for original PMAs

and one-third for PMA supplements.

Principal Findings

Premarket Notifications

(510(k)s)

From 1989 through 1991, the median time between the submission of a

510(k) application and FDA’s decision (total elapsed time) was relatively

stable at about 80 to 90 days. The next 2 years showed a sharp increase

that peaked at 230 days in 1993. Although the median review time showed

a decline in 1994 (152 days), it remained higher than that of the initial 3

years. (See figure 1.)

12We report our findings here in terms of two measures: median review time (that is, how long the case

representing the midpoint in review time took to complete review), and mean review time (the average

time to complete review). The median includes all cases (so long as at least one-half of cases

submitted in a given year were completed). By necessity, the mean includes only those cases that have

been completed. Both measures are reported by year of submission, not year of decision. For greater

detail on the two measures and the implications of their use, see pp. 12-14.

Page 5 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

Figure 1: Median Review Time for

510(k)s by Fiscal Yeara Days

0

50

100

150

200

250

300

1989 1990 1991 1992 1993 1994

Fiscal year

aThe median includes open cases.

Similarly, the mean also indicated a peak in review time in 1993 and a

subsequent decline. The mean review time increased from 124 days in 1989

to 269 days in 1993. In 1994, the mean dropped to 166 days; however, this

mean will increase as the 13 percent of the applications that remained

open are closed. (See table II.1.)

Of all the applications submitted to FDA to market new devices during the

period under review, a little over 90 percent were for 510(k)s. Between

1989 and 1994, the number of 510(k) applications remained relatively

stable, ranging from a high of 7,023 in 1989 to a low of 5,774 in 1991. In

1994, 6,446 applications were submitted.

Of the 40,950 510(k) applications submitted during the period under

review, approximately 73 percent were determined to be substantially

equivalent. (That is, the device is equivalent to a predicate device already

on the market and thus is cleared for marketing.) Only 2 percent were

found to be nonequivalent, and 6 percent remained open. Other

decisions—including applications for which a 510(k) was not required and

those that were withdrawn by the applicant—account for the rest. (See

appendix I for details on other FDA decision categories.)

Page 6 GAO/PEMD-96-2 FDA Medical Device Review Time
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For applications determined to be substantially equivalent, non-FDA

time—the amount of time FDA placed the application on hold while waiting

for additional information—comprised almost 20 percent of the total

elapsed time. (See table II.7.) Figure 2 displays FDA and non-FDA time to

determine equivalency for 510(k) applications.

Figure 2: Mean Time to Determine

Equivalency for 510(k)s by FDA and

Non-FDA Timea

Days

0

50

100

150

200

250

300

350

1989 1990 1991 1992 1993 1994

Fiscal year

Non-FDA time

FDA time

aOpen cases are not included. The means shown will increase when open cases are completed.

Premarket Approvals

(PMAs)

The trends in review time differed for original PMAs and PMA supplements.

There was no clear trend in review times for original PMA applications

using either medians or means since a large proportion of the applications

had yet to be completed. The median time between the submission of an

application and FDA’s decision (total elapsed time) fluctuated from a low of

414 days in 1989 to a high of 984 days in 1992. Less than 50 percent of the

applications submitted in 1994 were completed; thus, the median review

time was undetermined. (See figure 3.)

Page 7 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

Figure 3: Median Review Time for

Original PMAs by Fiscal Yeara Days

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1989 1990 1991 1992 1993

Fiscal year

aThe median includes open cases. Data for 1994 are omitted because less than 50 percent of the

applications submitted had been completed.

Except for 1989, the means were lower than the medians because of the

large number of open cases. The percent of applications that remained

open increased from 4 percent in 1989 to 81 percent in 1994. The means,

then, represent the time to a decision for applications that were less

time-consuming. When the open cases are completed, lengthy review

times will cause an increase in the means. (See table III.1.)

For PMA supplements, the median time ranged from 126 days to 173 days in

the first 3 years, then jumped to 288 days in 1992. In 1993 and 1994, the

median declined to 242 and 193 days, respectively. (See figure 4.)

Page 8 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

Figure 4: Median Review Time for PMA

Supplements by Fiscal Yeara Days

0

50

100

150

200

250

300

350

1989 1990 1991 1992 1993 1994

Fiscal year

aThe median includes open cases.

This trend was reflected in the mean review time that peaked at 336 days

in 1992. Although the mean dropped to 162 days in 1994, this is expected

to increase because 21 percent of the applications had not been completed

at the time of our study. (See table III.7.)

Applications for original PMAs made up less than 1 percent of all

applications submitted to FDA to market new devices in the period we

reviewed. PMA supplements comprised about 8 percent of the applications.

The number of applications submitted for PMA review declined each year.

In 1989, applications for original PMAs numbered 84. By 1994, they were

down to 43. Similarly, PMA supplements decreased from 804 in 1989 to 372

in 1994. (See tables III.1 and III.7.)

Of the 401 applications submitted for original PMAs, 33 percent were

approved, 26 were withdrawn, and nearly a third remained open. The

remainder (about 9 percent) fell into a miscellaneous category. (See

appendix I.) A much higher percentage of the 3,640 PMA supplements

(78 percent) were approved in this same period, and fewer PMA

supplements were withdrawn (12 percent). About 9 percent of the

Page 9 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

applications remained open, and 2 percent fell into the miscellaneous

category.

For PMA reviews that resulted in approval, non-FDA time constituted

approximately one-fourth of the total elapsed time for original PMAs and

about one-third for PMA supplements. The mean FDA time for original PMAs

ranged from 155 days in 1994 to 591 days in 1992. Non-FDA times for those

years were 34 days in 1994 and 165 days in 1992. For PMA supplements, FDA

review times were lower, ranging from a low of 105 days (1990) to a high

of 202 days (1992). Non-FDA time for those years were 59 days (1990) and

98 days (1992), respectively. (See table III.13.) Figures 5 and 6 display the

proportion of FDA and non-FDA time for the subset of PMAs that were

approved.

Figure 5: Mean Time to an Approval for

Original PMAs by FDA and Non-FDA

Timea

Days

0

100

200

300

400

500

600

700

800

900

1989 1990 1991 1992 1993

Fiscal year

Non-FDA time

FDA time

aData for 1994 are omitted because less than 50 percent of the applications submitted had been

completed. Open cases are not included. The mean times shown will increase when open cases

are closed.

Page 10 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

Figure 6: Mean Time to an Approval for

PMA Supplements by FDA and

Non-FDA Timea

Days

0

25

50

75

100

125

150

175

200

225

250

275

300

325

1989 1990 1991 1992 1993 1994

Fiscal year

Non-FDA time

FDA time

aOpen cases are not included. The mean times shown will increase when open cases are closed.

Investigational Device

Exemptions (IDEs)

For IDEs, the mean review time between submission and FDA action was 30

days, and it has not changed substantially over time. Unlike 510(k)s and

PMAs, IDEs are “deemed approved” if FDA does not act within 30 days. Of the

1,478 original IDE submissions from fiscal year 1989 to 1995, 33 percent

were initially approved (488) and 62 percent were denied or withdrawn

(909). The number of IDE submissions each year ranged from a high of 264

in 1990 to a low of 171 in 1994. (See table IV.1.)

Objectives, Scope,

and Methodology

Our objective was to address the following general question: How has the

time that 510(k), PMA, and IDE applications spend under FDA review

changed between fiscal year 1989 and the present? To answer that

question, we also looked at a subset of applications that were approved,

distinguishing the portion of time spent in FDA’s review process (FDA time)

from that spent waiting for additional information (non-FDA time). For

applications that were approved, we present the average number of

Page 11 GAO/PEMD-96-2 FDA Medical Device Review Time
B-261822 

amendments that were subsequently added to the initial application as

well as the average number of times FDA requested additional information

from the applicant. (Both of these activities affect FDA’s review time.)

We used both the median and mean to characterize review time. We use

the median for two reasons. First, a large proportion of the applications

have yet to be completed. Since the median is the midpoint when all

review times are arranged in consecutive order, its value can be

determined even when some applications requiring lengthy review remain

open. In contrast, the mean can only be determined from completed

applications. (In this case, applications that have been completed by

May 18, 1995.) In addition, the mean will increase as applications with

lengthy reviews are completed.

To illustrate, for applications submitted in 1993, the mean time to a

decision was 269 days for 510(k) applications that have been closed.

However, 3 percent of the applications have yet to be decided. If these

lengthy reviews were arbitrarily closed at May 18, 1995 (the cutoff date for

our data collection), the mean would increase to 285 days. In contrast, the

median review time (230 days) would remain the same regardless of when

these open applications were completed.

The second reason for using the median is that the distributions of review

time for 510(k), original PMA, and PMA supplement applications are not

symmetric, that is, having about the same number of applications requiring

short reviews as lengthy reviews. The median is less sensitive to extreme

values than the mean. As a result, the review time of a single application

requiring an extremely lengthy review would have considerably more

effect on the mean than the median. Figure 7 shows the distribution for

510(k)s submitted in 1993, the most recent year in which at least

95 percent of all 510(k) applications had been completed. The distribution

is skewed with a mean review time of 269 days and a median review time

of 222 days for all completed applications.13

13See appendix III for the distribution of review time for original PMAs and PMA supplements.

Page 12 GAO/PEMD-96-2 FDA Medical Device Review Time
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Figure 7: Time to a Decision for 510(k)s Submitted in Fiscal Year 1993a

100 200 300 400 500 600 700 800 900

0

50

100

150

200

250

Days

Frequency

Mean = 269

Median = 222

aThe number of cases in this frequency distribution is 6,101. (The one application with over 1,500

days was dropped from this figure.) As of May 18, 1995, 3 percent of applications submitted had

not been completed and were not included. When these applications are closed, the mean will

increase.

To provide additional information, we report on the mean review times as

well as the median. The discrepancy between the two measures gives

some indication of the distribution of review time. When the mean is larger

than the median, as in the case of the 510(k)s above, it indicates that a

group of applications required lengthy reviews.14 Another reason we report

14For original PMAs, the mean is smaller than the median. The smaller mean results from the large

number of open cases. Applications requiring lengthy reviews have yet to be completed. As these

reviews are completed, the mean will increase.

Page 13 GAO/PEMD-96-2 FDA Medical Device Review Time
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the means is that, until recently, FDA reported review time in terms of

means.

In appendix I, we provide the categories we used to designate the different

FDA decisions and how our categories correspond to those used by FDA.

Detailed responses to our study objective are found in tabular form in

appendixes II, III, and IV for 510(k)s, PMAs, and IDEs, respectively.

We report our findings according to the fiscal year in which the

applications were submitted to FDA. By contrast, FDA commonly reports

review time according to the fiscal year in which the review was

completed.15 Although both approaches measure review time, their

resultant statistics can vary substantially. For example, several complex

applications involving lengthy 2-year reviews submitted in 1989 would

increase the average review time for fiscal year 1989 in our statistics and

for fiscal year 1991 in FDA’s statistics. Consequently, the trend for review

time based on date-of-submission cohorts can differ from the trend based

on date-of-decision cohorts. (See appendix V for a comparison of mean

review time based on the two methods.)

The two methods provide different information and are useful for different

purposes. Using the date-of-decision cohort is useful when examining

productivity and the management of resources. This method takes into

consideration the actual number of applications reviewed in a given year

including all backlogs from previous years. Alternatively, using the

date-of-submission cohort is useful when examining the impact of a

change in FDA review policy, which quite often only affects those

applications submitted after its implementation.16 To minimize the effect

of different policies on review time within a cohort, we used the

date-of-submission method.

We conducted our work in accordance with generally accepted

government auditing standards between May and June 1995.

Agency Comments Officials from FDA reviewed a draft of this report and provided written

comments, which are reproduced in appendix VI. Their technical

15Using date-of-decision cohorts obviates the problem of open cases. Both means and medians can be

easily determined.

16FDA has indicated that it plans to include statistics on review time based on the year of submission in

its reports.

Page 14 GAO/PEMD-96-2 FDA Medical Device Review Time
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comments, which have been incorporated into the text where appropriate,

have not been reprinted in the appendix.

FDA believed that the report misrepresented the current state of the

program as the draft did not acknowledge recent changes in the review

process. FDA officials suggested a number of explanations for the apparent

trends in the data we reported (see appendix VI). Although recent

initiatives to improve the review process provide a context in which to

explain the data, they were outside the scope of our work. We were not

able to verify the effect these changes have actually had on review time.

To the extent that these changes did affect review time, they are reflected

in the review times as presented and are likely to be reflected in future

review times.

The agency also believed that the draft did not reflect the recent

improvements in review time. We provided additional measures of review

time in order to present the review times for the more recent years. We

have also included more information on the difference between the

date-of-submission and date-of-decision cohorts, and we have expanded

our methodological discussion in response to points FDA made on the

clarity of our presentation. (Additional responses to the agency comments

are included in appendix VI.)

As agreed with your office, unless you publicly announce its contents

earlier, we plan no further distribution of this report until 30 days after its

date of issue. We will then send copies to other interested congressional

committees, the Secretary of the Department of Health and Human

Services, and the Commissioner of Food and Drugs. Copies will also be

made available to others upon request.

Page 15 GAO/PEMD-96-2 FDA Medical Device Review Time
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If you or your staff have any questions about this report, please call me at

(202) 512-3092. The major contributors to this report are listed in appendix

VII.

Sincerely yours,

Kwai-Cheung Chan

Director of Program Evaluation

 in Physical Systems Areas

Page 16 GAO/PEMD-96-2 FDA Medical Device Review Time
Page 17 GAO/PEMD-96-2 FDA Medical Device Review Time
Contents

Letter 1

Appendix I 

FDA Decision Codes

and GAO’s Categories

22

Appendix II 

Premarket

Notification (510(k))

Tables II.1 - II.12

24

Appendix III 

Premarket Approval

Tables III.1 - III.18

39

Appendix IV 

Investigational Device

Exemption Tables IV.1

- IV.6

65

Appendix V 

Comparision in Table

V of Alternative

Methods for

Determining Average

Days to Decision by

Fiscal Year

73

Page 18 GAO/PEMD-96-2 FDA Medical Device Review Time
Contents

Appendix VI 

Comments From the

Food and Drug

Administration

74

Appendix VII 

Major Contributors to

This Report

87

Table Table I.1: Correspondence Between GAO Categories and FDA

Decision Codes

22

Figures Figure 1: Median Review Time for 510(k)s by Fiscal Year 6

Figure 2: Mean Time to Determine Equivalency for 510(k)s by

FDA and Non-FDA Time

7

Figure 3: Median Review Time for Original PMAs by Fiscal Year 8

Figure 4: Median Review Time for PMA Supplements by Fiscal

Year

9

Figure 5: Mean Time to an Approval for Original PMAs by FDA

and Non-FDA Time

10

Figure 6: Mean Time to an Approval for PMA Supplements by

FDA and Non-FDA Time

11

Figure 7: Time to a Decision for 510(k)s Submitted in Fiscal Year

1993

13

Figure III.1: Average Days to Decision on Premarket Approvals

by Milestone by Year, October 1, 1988 - May 18, 1995

42

Figure III.2: Time to a Decision for Original PMAs Submitted in

Fiscal Year 1989

44

Figure III.3: Time to a Decision for PMA Supplements Submitted

in Fiscal Year 1991

45

Figure VI.1: Total Elapsed Time for 510(k) Reviews, 1989-95:

Mean, Median for Closed Cases, and Median for All Casesa

84

Page 19 GAO/PEMD-96-2 FDA Medical Device Review Time
Contents

Abbreviations

CT Computed tomography

DCLD Division of Clinical Laboratory Devices

DCRND Division of Cardiovascular, Respiratory and Neurological

Devices

DGRD Division of General and Restorative Devices

DOD Division of Ophthalmic Devices

DRAER Division of Reproductive, Abdominal, Ear, Nose and Throat,

and Radiological Devices

FDA Food and Drug Administration

IDE Investigational device exemption

PMA Premarket approval

Page 20 GAO/PEMD-96-2 FDA Medical Device Review Time
Page 21 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix I 

FDA Decision Codes and GAO’s Categories

FDA uses different categories to specify the type of decision for 510(k)s,

PMAs, and IDEs. For our analysis, we collapsed the multiple decision codes

into several categories. The correspondence between our categories and

FDA’s are in table I.1.

Table I.1: Correspondence Between

GAO Categories and FDA Decision

Codes

Type of application GAO category FDA decision code

Premarket notification Equivalent Equivalent

Nonequivalent Nonequivalent

Other Additional information requested;

applicant cannot respond within 30

days

Forwarded to drugs/biologics

Deleted/duplicate

Deleted

Drug (CDER) review required

Exempted by regulation

General purpose article

Closeout letter issued

Not actively regulated

Not a device

Not a finished product

Not a required submission

Preamendment exempt

Refuse to accept

Reconditioner/remanufacturer

Transitional device

Withdrawn by applicant

Premarket approval Approved Approved

Denied Denied

Withdrawn Withdrawn

Other Abandoned

Converted

Reclassified

Other

(continued)

Page 22 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix I 

FDA Decision Codes and GAO’s Categories

Type of application GAO category FDA decision code

Investigational device

exemption

Approved Approved

Approved with conditions

Deemed approved and request

information

Denied Disapproved

Refuse to accept

Withdrawn Deemed approved/immediate

withdraw

Immediate withdrawal by FDA

Withdrawn by sponsor

Other Acknowledge incoming

Study exempt from part 812

Inadequate incoming

Incomplete

Product jurisdiction pending

Product jurisdiction transferred

No response necessary

Nonsignificant risk device study

Other

Request for progress report

Investigation terminated/

inadequate/no final report

Telephone response

Voluntary termination requested

Page 23 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Tables Page

Table II.1: Average Days to Decision on 510(k)s

and Number of Open Cases by Fiscal Year 27

Table II.2: Summary of Average Days to Decision on 510(k)s

and Number of Open Cases 28

Table II.3: Average Days to Decision and Number of Open

Cases for 510(k)s by Class of Medical Device 29

Table II.4: Average Days to Decision and Number of Open Cases

for 510(k)s by Tier of Medical Device 30

Table II.5: Average Days to Decision and Number of Open Cases

for 510(k)s by Medical Specialty of Device 31

Table II.6: Average Days to Decision and Number of Open Cases

for 510(k)s by Reviewing Division 32

Table II.7: Average Days to Equivalency for 510(k)s

by Fiscal Year 33

Table II.8: Average Days to Equivalency for 510(k)s by Class,

Tier, Medical Specialty, and Division 34

Table II.9: Average Days to Equivalency for 510(k)s by Class

of Medical Device 35

Table II.10: Average Time to Equivalency for 510(k)s by Tier

of Medical Device 36

Table II.11: Average Time to Equivalency for 510(k)s by

Medical Specialty of Device 37

Table II.12: Average Time to Equivalency for 510(k)s by 

Reviewing Division 38

Page 24 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Review Time for

Premarket

Notification

The following tables present the data for premarket notifications, or

510(k)s, for fiscal years 1989 through May 18, 1995. The first set of tables

(tables II.1 through II.6) presents the time to a decision—from the date the

application is submitted to the date a decision is rendered.

We first present a summary table on the time to a decision by fiscal year

(table II.1). The grand total for the number of applications includes open

cases—that is, applications for which there had not been any decision

made as of May 18, 1995. As the distribution for time to a decision is not

symmetric (see figure 1 in the letter), we present the means and

percentiles to characterize the distribution. (The means and percentiles do

not include open cases.)

The second table is a summary of the time to a decision by class, tier,

medical specialty of the device, and reviewing division (table II.2). The

next four tables (II.3 through II.6) provide the details for these summary

tables. The totals in these tables include only applications for which a

decision has been rendered.

The class, tier, and medical specialty of some of the devices have yet to be

determined and are designated with N/A. Medical specialties other than

general hospital or general and plastic surgery include anesthesiology;

cardiovascular; clinical chemistry; dental; ear, nose, and throat;

gastroenterology/urology; hematology; immunology; microbiology;

neurology; obstetrics/gynecology; ophthalmic; orthopedic; pathology;

physical medicine; radiology; and clinical toxicology.

The five reviewing divisions in FDA’s Center for Devices and Radiological

Health are Division of Clinical Laboratory Devices (DCLD); Division of

Cardiovascular, Respiratory and Neurological Devices (DCRND); Division of

General and Restorative Devices (DGRD); Division of Ophthalmic Devices

(DOD); and Division of Reproductive, Abdominal, Ear, Nose and Throat,

and Radiological Devices (DRAER).

The second set of tables (tables II.7 through II.12) presents the mean time

to determine equivalency. We provide the means for total FDA time,

non-FDA time, and total elapsed time. FDA time is the total amount of time

the application was under FDA review including queue time—the time to

equivalency without resetting the FDA review clock. The total elapsed time,

the duration between the submission of the application and FDA’s decision,

equals the sum of the FDA and non-FDA time.

Page 25 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

We deleted cases that had missing values or apparent data entry errors for

the values relevant to calculating FDA and non-FDA time. Therefore, the

total number of applications determined to be equivalent in this group of

tables differs from that in the first set. Again, we have two summary tables,

followed by four tables providing time to determine equivalency by class,

tier, medical specialty, and reviewing division (tables II.7 through II.12).

Page 26 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 27 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 28 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 29 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 30 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 31 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 32 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 33 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 34 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 35 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 36 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 37 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix II 

Premarket Notification (510(k)) Tables II.1 -

II.12

Page 38 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Tables Page

Table III.1: Average Days to Decision on Original PMAs by Fiscal

 Year and Number of Open Cases 47

Table III.2: Summary of Average Days to Decision on PMAs and

Number of Open Cases 48

Table III.3: Average Days to Decision on Original PMAs by Class

of Medical Device and Number of Open Cases 49

Table III.4 Average Days to Decision on Original PMAs by Tier

of Medical Device and Number of Open Cases 50

Table III.5: Average Days to Decision on Original PMAs by

Medical Specialty of Device and Number of Open Cases 51

Table III.6: Average Days to Decision on Original PMAs by

Reviewing Division and Number of Open Cases 52

Table III.7: Average Days to Decision on PMA Supplements by

Fiscal Year and Number of Open Cases 53

Table III.8: Summary of Average Days to Decision on PMA

Supplements and Number of Open Cases 54

Table III.9: Average Days to Decision on PMA Supplements by

Class of Medical Device and Number of Open Cases 55

Table III.10: Average Days to Decision on PMA Supplements by

Tier of Medical Device and Number of Open Cases 56

Table III.11: Average Days to Decision on PMA Supplements by

Medical Specialty of Device and Number of Open Cases 57

Table III.12: Average Days to Decision on PMA Supplements by

Reviewing Division and Number of Open Cases 58

Table III.13: Average Days to Approval for PMAs by Fiscal Year 59

Table III.14: Average Days to Approval for PMAs by Class, Tier,

Medical Specialty, and Reviewing Division 60

Page 39 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Table III.15: Average Days to Approval for PMAs by Fiscal Year

and Class of Medical Device 61

Table III.16: Average Days to Approval for PMAs by Fiscal Year

and Tier of Medical Device 62

Table III.17: Average Days to Approval for PMAs by Fiscal Year

and Medical Specialty of Device 63

Table III.18: Average Days to Approval for PMAs by Fiscal Year

and Reviewing Division 64

Page 40 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Review Time for

Premarket Approval

In reviewing a PMA application, FDA conducts an initial review to determine

whether the application contains sufficient information to make a

determination on its safety and effectiveness. A filing decision is

made—filed, filed with deficiencies specified, or not filed—based on the

adequacy of the information submitted. The manufacturer is notified of the

status of the application at this time, especially since deficiencies need to

be addressed.

As part of the substantive review, a small proportion of PMA applications

are also reviewed by an advisory panel.1

 These panels include clinical

scientists in specific medical specialties and representatives from both

industry and consumer groups. The advisory panels review the

applications and provide recommendations to the agency to either

approve, deny, or conditionally approve them. FDA then makes a final

determination on the application.

To examine in greater detail those cases where the intermediate

milestones were applicable, we calculated the average duration between

the various dates—submission, filing, panel decision, and final decision.

The number of applications differs for each of the milestones as not all

have filing or panel dates. (See figure III.1.)

1

Of the 401 original PMAs, 87 (22 percent) were reviewed by panels. Of the 3,640 PMA supplements,

only 9 (0.2 percent) received panel review.

Page 41 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Figure III.1: Average Days to Decision on Premarket Approvals by Milestone by Year, October 1, 1988 - May 18, 1995

Page 42 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

The following tables present information on review time for PMA

applications for fiscal years 1989 through 1995. Original PMA applications

are distinguished from PMA supplements. Some observations were deleted

from our data because of apparent data entry errors. The first set of tables

(tables III.1 through III.6) presents the time to a decision for original

PMAs—from the date the application is submitted to the date a decision is

rendered. The second set of tables (tables III.7 through III.12) provides

similar information, in the same format, for PMA supplements.

We first present a summary table on the time to a decision by fiscal year

(tables III.1 and III.7). Again, the grand total for the number of applications

includes the number of open cases—that is, applications for which there

had not been any decision made as of May 18, 1995. As with 510(k)s, the

distributions of time to a decision for original PMAs and PMA supplements

are not symmetric. Thus we report means and percentiles to characterize

these distributions. (These means and percentiles do not include open

cases.)

Figure III.2 presents the distribution for original PMAs submitted in 1989,

the most recent year for which at least 95 percent of the applications had

been completed. Figure III.3 presents the distribution for PMA supplements

submitted in 1991, the most recent year with at least a 95-percent

completion date.

Page 43 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Figure III.2: Time to a Decision for Original PMAs Submitted in Fiscal Year 1989a

200 400 600 800 1000 1200 1400 1600 1800

0

2

4

6

8

10

Days

Frequency

Mean = 513

Median = 409

aThe number of cases in this frequency distribution is 81. As of May 18, 1995, about 4 percent of

the applications submitted had not been completed and were not included.

Page 44 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Figure III.3: Time to a Decision for PMA Supplements Submitted in Fiscal Year 1991a

200 400 600 800 1000 1200

0

5

10

15

20

25

30

35

40

Days

Frequency

Mean = 261

Median = 154

aThe number of cases in this frequency distribution is 577. As of May 18, 1995, 3 percent of the

applications submitted had not been completed and were not included.

Page 45 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

The second table is a summary of the time to a decision by class, tier,

relevant medical specialty of the device, and reviewing division (tables

III.2 and III.8). The two summary tables are followed by four tables (tables

III.3 through III.6 and III.9 through III.12) presenting the details by class,

tier, medical specialty, and reviewing division. The totals in these tables

include only applications for which a decision has been rendered.

The class, tier, and medical specialty of some of the devices have yet to be

determined and are designated with N/A. Medical specialities other than

cardiovascular or ophthalmic include anesthesiology; clinical chemistry;

dental; ear, nose, and throat; gastroenterology/urology; general and plastic

surgery; general hospital; hematology; immunology; microbiology;

neurology; obstetrics/gynecology; orthopedic; pathology; physical

medicine; radiology; and clinical toxicology.

The third set of tables provides information on the time to an approval, for

both original PMAs and PMA supplements (tables III.13 through III.18). Four

different measures of duration are provided—total FDA time, non-FDA time,

total elapsed time, and FDA review time. Total FDA time is the amount of

time the application is under FDA’s review process. Non-FDA time is the

time the FDA clock is suspended waiting for additional information from

the applicant. The total elapsed time, the duration from the date the

application is submitted to the date of FDA’s decision, equals the sum of

total FDA and non-FDA time. FDA review time is FDA time for the last

cycle—excluding any time accrued before the latest resetting of the FDA

clock.

Again, we first provide a summary table for time to an approval by fiscal

year (table III.13). In this table, we also provide the number of

amendments or the number of times additional information was added to

the initial submission. Not all amendments were for information requested

by FDA as can be seen from the number of requests for information.

Table III.13 is followed by a summary by class, tier, medical specialty, and

reviewing division (table III.14). Tables III.15 though III.18 provide the

details for these two summary tables.

Page 46 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 47 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 48 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 49 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 50 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 51 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 52 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 53 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 54 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 55 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 56 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 57 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 58 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 59 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 60 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 61 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 62 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 63 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix III 

Premarket Approval Tables III.1 - III.18

Page 64 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Tables Page

Table IV.1: Average Days to Decision on Investigational Device

Exemptions by Fiscal Year 67

Table IV.2: Summary of Average Days to Decision on

Investigational Device Exemptions 68

Table IV.3: Average Days to Decision on Investigational Device

Exemptions by Class of Medical Device 69

Table IV.4: Average Days to Decision on Investigational Device

Exemptions by Tier of Medical Device 70

Table IV.5: Average Days to Decision on Investigational Device

Exemptions by Medical Specialty of Device 71

Table IV.6: Average Days to Decision on Investigational Device

Exemptions by Reviewing Division 72

Page 65 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Review Time for

Investigational Device

Exemptions

The following tables present the average days to a decision for

investigational device exemptions. The first table presents the averages for

the years from October 1, 1988, through May 18, 1995. This is followed by

summaries by class, tier, medical specialty, and then reviewing division.

The next four tables (tables IV.3 through IV.6) provide the details for these

summary tables.

Page 66 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 67 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 68 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 69 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 70 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 71 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix IV 

Investigational Device Exemption Tables

IV.1 - IV.6

Page 72 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix V 

Comparision in Table V of Alternative

Methods for Determining Average Days to

Decision by Fiscal Year

Alternative

Calculation of Review

Time by Year of

Decision

We reported our findings according to the fiscal year in which the

applications were submitted to FDA (date-of-submission cohort). By

contrast, FDA commonly reports review time according to the fiscal year in

which the review was completed (date-of-decision cohort). This led to

discrepancies between our results and those reported by FDA. The

following table illustrates the differences in calculating total elapsed time

by the year that the application was submitted and the year that a decision

was rendered. Comparisons are provided for 510(k)s, PMA supplements,

original PMAs, and IDEs.

Our dataset did not include applications submitted before October 1, 1988.

Consequently, the results presented in the following table understated the

number of cases, as well as the elapsed time, when calculated by the year

of decision. That is, an application submitted in fiscal year 1988 and

completed in 1989 would not have been in our dataset.

Page 73 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

Note: GAO comments

supplementing those in the

report text appear at the

end of this appendix.

Page 74 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 1.

Page 75 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 2.

See comment 3.

Page 76 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 4.

See comment 5.

Page 77 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 6.

See comment 7.

See comment 8.

Page 78 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 1.

See comment 9.

Page 79 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

See comment 10.

FDA also provided

technical comments,

which have been

incorporated into the text

where appropriate but

have not been reprinted

here.

Page 80 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

Page 81 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

Page 82 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

The following are GAO’s comments on the August 2, 1995, letter from FDA.

GAO Comments 1. The purpose of our review was to provide to FDA’s congressional

oversight committee descriptive statistics on review time for medical

device submissions between 1989 and May 1995. It was not to perform an

audit of whether FDA was in compliance with statutory review time, nor to

examine how changes in FDA management practices may have resulted in

shortening (or lengthening) review times. FDA officials suggested that a

number of process changes and other factors may have contributed to the

trends we reported—for example, the increased complexity of the typical

submission that resulted from the agency’s exemption from review of

certain low-risk devices. We are not able to verify the effect changes have

actually had on review time, and it may be that it is still too early for their

impact to be definitively assessed.

2. In discussing our methodology in the draft report, we noted the

differences between FDA’s typical method of reporting review time

according to the year in which action on applications is finalized, as

opposed to our method of assigning applications to the year in which they

were submitted. We also included an appendix that compares the results

of the two different approaches. (See appendix V.) We agree with FDA that

it is important for the reader to understand these differences and have

further expanded our discussion of methodology to emphasize this point.

(See p. 14.)

3. We agree with FDA that our report “deals only with calculations of

averages and percentiles”—that is, with means, medians (or 50th

percentile), as well as the 5th and 95th percentiles. However, FDA’s

suggested additions do not extend beyond such descriptive statistics.

We also agree that mean review times in the presence of numerous open

cases may not be meaningful. For this reason, we have included open

cases in our tables that report review time, but we have excluded them

from the calculation of means. FDA suggests that we include open cases in

our calculation of medians. We have adopted this suggestion and

presented our discussion of trends in terms of the median review time for

all cases. It should be noted, however, that including open cases increases

our estimate of review time. (For example, including open cases raises the

calculation of 510(k) median review time from the 126 days we reported

for 1994 to 152 days.)

Page 83 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

Figure VI.1 depicts the relationship among the three measures of elapsed

time for 510(k) submissions: the mean of closed cases, the median of

closed cases, and the median of all cases. The two measures of closed

cases reveal roughly parallel trends, with median review time averaging

some 45 days fewer than mean review time. The two estimates of median

review time are nearly identical from 1989 through 1990 since there are

very few cases from that period that remain open. The divergence between

the two medians increases as the number of open cases increases in recent

years until 1995, when the median, including open cases, is larger than the

mean of closed cases.

Figure VI.1: Total Elapsed Time for

510(k) Reviews, 1989-95: Mean, Median

for Closed Cases, and Median for All

Casesa

Days

0

50

100

150

200

250

300

1989 1990 1991 1992 1993 1994 1995

Fiscal Year

Mean (Closed Cases)

Median (Closed Cases)

Median (All Cases)

aFiscal year 1995 includes actions only through May 18, 1995.

Page 84 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

4. While we are unable to reproduce the calculations performed by FDA, we

agree in general with the trends indicated by FDA. Specifically,

• Our calculations, as presented in our draft report tables II.7 and following,

showed a decrease from 1993 to 1994 in FDA review time for finding a

510(k) submission substantially equivalent. By our calculation, this

declined from a mean of 173 days in 1993 to 100 days in 1994.

• The proportion of 510(k) applications reaching initial determination within

90 days of submission increased from 15.8 percent in 1993 to 32 percent in

1994 and 57.9 percent between October 1, 1994, and May 18, 1995.

Clearly, since 1993, more 510(k) cases have been determined within 90

days, and the backlog of undetermined cases has been reduced. Because a

review of the nature and complexity of the cases still open was beyond the

scope of this study, we cannot predict with certainty whether, when these

cases are ultimately determined, average review time for 1995 cases will

be shorter than for cases submitted in 1993.

5. FDA time was reported in our draft report tables II.7 through II.12, and

findings contrasting the differences between FDA time and non-FDA time

were also included. Additional language addressing this distinction has

been included in the text of the report.

6. FDA’s contends that 1989 was an atypical year for 510(k) submissions

and therefore a poor benchmark. However, we do not believe that starting

our reporting in 1989 introduced any significant bias into our report of the

510(k) workload. Indeed, our draft report concluded that the number of

510(k) submissions had “remained relatively stable” over the 1989-94

period. If we had extrapolated the data from the first 7-1/2 months of 1995

to a full year, we would have concluded that the current fiscal year would

have a substantially lower number of 510(k) submissions (16 percent to

31 percent) than any of the previous 6 years.

7. The tier classification was created by FDA to manage its review

workload; however, it was not our intention to evaluate or in any way

assess the use of tiers for such purposes. The tier classification was based

on “the potential risk and complexity of the device.” Accordingly, both

class and tier provide a rough indication of a device’s complexity.

8. We agree that our draft report aggregated original PMA submissions and

PMA supplements in summarizing its findings. We have now disaggregated

PMA statistics throughout.

Page 85 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VI 

Comments From the Food and Drug

Administration

9. We interpret the figures presented by FDA to represent the mean number

of days elapsed between receipt (or filing) of a PMA submission and a given

month for cases that have not been decided. We agree with FDA that the

average review time for open original PMAs does not appear to have

increased substantially since the beginning of calendar 1994 and that the

average review time has decreased for PMA supplements since late 1994.

Decreasing these averages is the product of either an increasing number of

new cases entering the system or of closing out older cases in the backlog

or both. Since the number of PMAs (originals and supplements) submitted

in recent years has declined, the evidence suggests that the drop in

average time for pending PMA supplements resulted from eliminating

lengthy backlogged cases.

10. As noted earlier, assessing the impact of specific management

initiatives is beyond the scope of this report. However, we do agree with

FDA that the approval rate for initial IDE submissions doubled between 1994

and 1995; by our calculations, it increased from 25 percent to 54 percent.

We have not independently examined the total time to approval for all

IDEs.

Page 86 GAO/PEMD-96-2 FDA Medical Device Review Time
Appendix VII 

Major Contributors to This Report

Program Evaulation

and Methodology

Division

Robert E. White, Assistant Director

Bertha Dong, Project Manager

Venkareddy Chennareddy, Referencer

Elizabeth Scullin, Communications Analyst

(973425) Page 87 GAO/PEMD-96-2 FDA Medical Device Review Time
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