Blog

Archive for De Novo

Classification Recommendation – How to write one for a De Novo request

This article explains how to write your classification recommendation for a De Novo Classification Request using a risk-based approach.

Classification Recommendation 1024x678 Classification Recommendation   How to write one for a De Novo request

“Automatic Class III Designation” does not mean that your device is a Class III device. That phrase means that the device is new, and therefore it will be automatically classified as Class III until a company submits a De Novo Classification Request. You and your company, not the FDA, should make the classification recommendation and propose the regulatory pathway for a new device. Submitting a 513g request is an option, but a 513g request involves paying the FDA money to write a classification recommendation. The FDA will always be more conservative in their assessment than the manufacturer.

Although no FDA guidance explains how to write a classification recommendation, companies have been writing these documents for years–for Technical Files. Most countries have risk-based classification rules, while the FDA’s product classification database is centered upon precedents and adjusted over time by historical trends of adverse events and recalls. Therefore, you should write a classification recommendation for the FDA that is focused on a documented risk assessment. Your approach will also need to be modified to include classification information for similar indications for use and technological characteristics that are already established in the US market.

Most Common Mistake in Writing a Classification Rationale 

Many people mistakenly write a short classification rationale for a technical file, which simply states which classification rule applies and why. Although this approach is acceptable for a Declaration of Conformity, you must provide a comprehensive classification rationale in your technical file. First, you need to make sure that there is only one classification rule that applies. For example, classification rules fall into four general categories:

  1. Non-invasive Devices
  2. Invasive Devices
  3. Active Devices
  4. Special Rules

The software was haphazardly added to the active devices category until recently, and special rules were created to address emerging areas of interest and concern. Therefore, most active devices have a second rule that applies regarding the invasive nature of the device–or lack thereof. In order to write a comprehensive classification rationale, you need to review each classification rule and document your explanation for why it applies or does not apply to your device.

A Classification Recommendation Compares Indications for Use

The FDA does have classification rules, but the rules are not 13 numbered items in the Code of Federal Regulations (CFR). The FDA expects a risk assessment of comparing your device with existing devices on the US market. The basis of comparison should be: 1) the indications for use and 2) the technological characteristics. First, you should identify other devices that have similar indications for use. For example, a device intended for home use or over-the-counter (OTC) use represents a higher risk to patients and users than a device intended for prescription use only. Patients may fail to identify contraindications for a device properly, or the lack of formal medical training may result in use errors that would not occur when a physician uses the same device.

Other aspects of indications for use that impact the risk assessment are the part of the body where your device will be used and the duration for use. For example, implants are higher risk than non-implants, because implants are in contact with the body for a much longer period of time. Implants can also expose the body to systemic risks, while a surface contacting device is likely only to have a localized effect. Degradation of implants also exposes the body small particles, with more surface area, that can travel from one part of the body to another.

If your device is used for life support, the device will also be considered a higher risk than devices that are not required for life support. If your device is the only device used for diagnosis, this also represents a higher risk than a device that acts as an adjunct to other devices. Finally, if your device is an accessory to other devices that are high risk, your device may be considered a higher risk as well–especially if it controls the higher risk device.

In your analysis, you need to identify devices that are already on the US market that have similar indications for use. Usually, those devices will be Class II devices. However, if some of those devices are Class I or Class III, you will need to be more careful with how you differentiate your indications for use from those other devices.

A Classification Recommendation Compares Technological Characteristics

When comparing technological characteristics, the following aspects should be considered: 1) materials, 2) design, 3) energy source, and 4) other design features. For example, absorbable materials are generally considered higher risk than devices that are not absorbable. Sterile devices are generally higher risk than non-sterile devices because the failure of the sterilization process or the package integrity can result in serious infections and death. Devices that are electrically powered are usually considered higher risk than devices that are not powered. Finally, software-controlled devices that provide feedback control are considered higher risk than a device that does not have feedback control. Each technological characteristic also represents a different category of hazard. Hazard categories are listed in Table E1 of Annex E in ISO 14971:2007. These include chemical, biological, electrical, radiation, etc.

Once you have identified the Classification of other devices with similar indications for use and technological characteristics, you need to estimate the risks for each hazard identified. This involves more than just listing hazards and assigning scores for severity and probability for the occurrence of harm. Severity should consider the type of injuries, a number of injuries, and the duration of harm. Probability should consider the frequency of events (P1), and the probability of events resulting in injury (P2). These risk estimates also require clinical data.

Benefit/Risk Analysis

In the end, you prepare a benefit/risk analysis for your device. This is much more than a statement that benefits outweigh the risks. You need to identify the clinical benefits of your device when compared to alternative treatments. You also need to analyze risks relative to alternative treatments. You will need to prepare this as a summary of risks–not a list of hazards. Ultimately, your benefits should be equivalent to the benefits of existing devices on the market or better, and the risks should be equivalent to existing devices on the market or less.

Examples of Classification Recommendation

Eight different medical devices are legally marketed in the USA for weight loss or weight management:

  1. Lap-Band Adjustable Gastric Banding System – Class III, PMA
  2. Maestro Rechargeable System – Class III, PMA
  3. ORBERA Intragastric Balloon System – Class III, PMA
  4. Obalon Balloon System – Class III, PMA
  5. TransPyloric Shuttle/TransPyloric Shuttle Delivery Device – Class III, PMA
  6. AspireAssist – Class III, PMA
  7. Sensor Monitored Alimentary Restriction Therapy (SMART) Device – Class II, De Novo
  8. Plenity – Class II, De Novo

The indications for use for these products are similar, but not identical. Plenity is indicated for patients with a BMI of 25 – 40 kg/m2. In comparison, ORBERA is indicated for patients with a BMI of 30-40 kg/m2, and AspireAssist is indicated for patients with a BMI of 35-55 kg/m2. All three of these indications have overlapping BMI ranges. However, the clinical benefits to a person with a BMI of 25 kg/m2 are not the same as the clinical benefits to a person with a BMI of 40 or 50 kg/m2. Therefore, these minor differences in BMI can have a significant impact upon the benefit/risk analysis used for a De Novo approval decision and the Classification (i.e., Class II or Class III) determined by the FDA.

The only two weight management devices that received the approval of the De Novo Classification Request had very different technological characteristics from the other six devices. All six of Class III, PMA devices, are implants, while the Class II devices are not implants. The risks associated with implants is much greater than non-implants. The risk of implants breaking or leaking, and the difficulty in removing an implant, are just two of the considerations that must be evaluated in deciding whether an implantable device should be a Class II or Class III device.

Posted in: De Novo

Leave a Comment (0) →

De Novo pre IDE Meeting

The article describes the most critical part of the preparation for a De Novo Classification Request, the De Novo pre IDE meeting.pre IDE Meeting Timeline De Novo pre IDE Meeting

There are two critical differences between a De Novo classification request and a 510k submission. First, 510k clearance is based upon a substantial equivalence comparison of a device and a predicate device that is already marketed in the USA, while a De Novo classification is based upon a benefit-risk analysis of a device’s clinical benefits compared with the risk of harm to users and patients. Second, 510k clearance usually does not require clinical data to demonstrate safety and efficacy, while a De Novo classification request usually does require clinical data to demonstrate safety and efficacy. Therefore, it makes sense that the two most common challenges for innovative medical device companies are: 1) learning how to write a benefit-risk analysis, and 2) designing a clinical study. Success with both of these tasks can be significantly improved by requesting a De Novo pre IDE meeting with the FDA.

Benefit-Risk Analysis Questions to Ask During a De Novo pre IDE Meeting

Most device companies are only familiar with substantial equivalence comparisons–not a benefit/risk analysis. The statement “the benefits outweigh the risks” is not a benefit/risk analysis. The European MDD requires a benefit/risk analysis (mentioned eight times), while Regulation (EU) 2017/745 mentions benefit/risk 69 times. Despite the obvious increased emphasis on benefit/risk analysis in the new EU Regulations, the new ISO 14971 standard that is expected to be released next month still does not require a benefit/risk analysis for all risks as required by the regulations. The international standard also does not clearly explain how to perform a benefit/risk analysis. The best explanation for how to perform a benefit/risk analysis is provided in the FDA guidance.

In addition to reading that guidance, you will need to systematically identify all of the current alternative methods of treatment, diagnosis, or monitoring for your intended use. Therefore, you should ask in a pre-submission meeting if there are any additional devices or treatments that the FDA feels should be considered. You should review each of the alternative treatments for clinical studies that may help you in the design of your clinical study. You should carefully review the available clinical data for alternative treatments to help you quantify the risks and benefits associated with those treatments too. Finally, you should consider whether one or more of these alternative treatments might be a suitable control for your clinical study. Ideally, your clinical study design will show that the benefits of your device are greater, and the risks are less, but either may be enough for approval of your classification request. If you think the risks of your device are significantly less than alternative treatments, then ask the FDA about using this factor as an endpoint in your study design.

Clinical Study Design Considerations

Ideally, there is already a well-accepted clinical model for assessing efficacy for your desired indications. This means multiple, published, peer-reviewed journal articles. You might have a better method for evaluating subjects, but don’t propose that method instead of a “gold standard.” If you feel strongly that your method is more appropriate, propose both methods of evaluation. You also need multiple evaluators who can be objective. Randomization, blinding, and monitoring of clinical studies is critical to ensure an unbiased evaluation of clinical results.

You also need to design your study with realistic expectations. Murphy’s law is always active. That means, “things will go wrong in any given situation if you give them a chance.” Therefore, you must avoid optimism and devise methods for detecting errors quickly. This is why electronic data capture systems and eSource is preferred for data collection instead of the manual collection of data on paper case study forms. Not only does it reduce errors in data collection, but it also facilitates remote monitoring of clinical sites. This includes asking questions that are open-ended or quantitative–instead of Yes/No questions or qualitative evaluations that encourage subjectivity. You can always anticipate every mistake that will be made, and open-ended questions often capture essential data that would otherwise be lost. Asking the quantitative questions also will provide you with additional data you can analyze, which may reveal unexpected relationships or help you to explain unexpected results. To help facilitate the development of these questions, try asking yourself how you could detect an error for each data point you are collecting. Then add a detection mechanism to your data collection plan wherever and whenever you can.

Goals of De Novo pre IDE Meeting

A pre-IDE meeting is not typically your first pre-submission meeting with the FDA. Usually, your first pre-submission meeting is to verify that the FDA agrees that the regulatory pathway is a De Novo classification request rather than a 510(k) submission. Hopefully, you also were able to review your overall testing plan with the FDA during your first pre-submission meeting. You may have even reviewed a clinical synopsis with the FDA during your initial pre-submission meeting. During the pre-IDE meeting, your goal is to finalize your clinical study protocol. That doesn’t mean that the FDA should agree 100% with your draft protocol. You want positive and negative feedback on all aspects of your protocol before the IDE submission. During the IDE review, changes will be made.

The most important aspects of getting right before the IDE submission are the fundamentals. Most of my De Novo clients feel that a control group is not possible, because they think that test subjects will know when a sham is used. However, trying to avoid a control group is nearly impossible. The most important factors for why a control group is needed are:

  • you need to minimize differences between experimental and control subjects, but you can’t do that if you are relying on data from other clinical studies
  • you also need to ensure that your evaluation methods are identical, which is nearly impossible when performed by different people, at different facilities, using slightly different protocols

Another area of weakness in most draft clinical protocols is the method of evaluation. Specifically:

  • Who is doing evaluations?
  • Which endpoints are important?
  • When are your endpoints?
  • What are your acceptance criteria?

The last area to consider in a pre-IDE meeting is your statistical plan. You need a statistical plan, but the statistical analysis seldom appears to be the reason for the rejection of clinical data. The reason is that changes can be made to your statistical analysis of data after the study is completed, but you can’t change the data once the study is over. The FDA is now accepting of adaptive designs that allow the company to analyze data during the study to recalculate the ultimate sample size needed based upon actual data rather than initial assumptions.

Other De Novo Classification Request Resources

On Thursday, October 17, we presented a live webinar showing medical device companies on how to avoid a stunning disaster. Click here to access the webinar recording. We recorded another webinar about preparation De Novo Classification Requests that you can download from our website. I wrote a blog about De Novo classification requests. You can also learn a lot about how to Design your own De Novo clinical study by reviewing the Decision Summaries published by the FDA for each De Novo in the list of De Novo classification requests. Finally, the FDA pre-sub guidance 2019 is an invaluable resource for preparing any pre IDE meeting request.

Posted in: De Novo

Leave a Comment (0) →