Issue 243
Welcome back to E&O: SaMD, a paying subscribers-only weekly newsletter focused on the world of digital pharma products, prescription digital therapeutics and other FDA-regulated digital health.
E&O: Software as a Medical Device
One quick follow-up from last week before we dig in…
- Click Therapeutics sent me a note in response to my reporting last week about its Series C round. Just as a reminder: I scooped the dollar amounts that added up to Click’s Series C, which officially remains undisclosed: $40 million from Medidata + nearly $9 million in converted debt from Suvretta Capital + $3 million from unnamed investor(s). That comes to about $52 million for the Series C, which matches the company’s $52 million Series B from 2021. That led me to wonder if it was a down round or a flat round. I speculated that given the dollar amounts and the current funding environment for digital health companies — it likely was. Click says: Not true. In an email to me, Click did not confirm or deny the numbers I put together but it said on the record that: “To date, all of Click’s financing rounds have been completed at substantially higher valuations than the one prior. We have not had a down or flat round.” Impressive.
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Scoop: Whoop’s first FDA clearance (and what its second clearance will likely be)
While the company hasn’t announced this yet, the FDA recently granted wearable device maker Whoop its first FDA 510(k) clearance for an over the counter Software as a Medical Device named Whoop ECG (electrocardiogram) Feature (1.0). And E&O has reason to believe an abnormal rhythm notification feature is likely the second SaMD that Whoop has submitted to the FDA for clearance (more on that at the end of this article).
The product code for the FDA-cleared feature is QDA, the same one the FDA created after its surprising and confusing De Novo clearance for the same feature on the Apple Watch back in 2018. Since then Fitbit/Google, Garmin, and Samsung have all secured 510(k) clearances for similar OTC ECG features for their wearable devices. This OTC ECG feature is not for diagnosis. Here’s the official definition of this product code (QDA):
“An electrocardiograph software device for over-the-counter use creates, analyzes, and displays electrocardiograph data, and can provide information for identifying cardiac arrhythmias. This device is not intended to provide a diagnosis.”
Whoop officially submitted its ECG feature for FDA clearance in October 2024 and received the clearance letter in early April 2025. We don’t have access to the FDA’s summary document for this clearance yet, but the indication will be similar to the generic device definition listed above. E&O readers saw this one coming since at least 2021 when I reported on a Whoop job posting that made it clear the company was pursuing FDA clearances:
“As an extension of that mission, we are exploring new opportunities to deliver value via Software as a Medical Device. This will propel WHOOP into the broader health and wellness arena with a creditable solution enabling us to further move the needle on public health. As a Tech Lead on the FDA team, you’ll be leading the development of a brand new product offering. A key component to leading the team will be developing software under a Quality Management System (QMS) that is compliant with the FDA guidelines. In addition, you will be collaborating with quality, legal, and other engineering teams to assess risk, development mitigation strategies, and play a vital role in ensuring compliance is met.”
UPDATE (May 5, 2025): The FDA has just posted the summary document for the initial 510(k). It shows that Whoop’s ECG Feature is substantially equivalent to Apple Watch’s. Whoop’s ECG feature includes Whoop’s app, which runs on iPhones and Androids. The device also includes Whoop’s strap, which includes an ECG module with sensors embedded. Here is the official Indications for Use language, which closely matches Apple’s ECG 2.0 clearance language, for Whoop’s first 510(k):
“The WHOOP ECG Feature is a software-only mobile medical application intended for use with the WHOOP Strap to create, record, store, transfer, and display a single-channel electrocardiogram (ECG) qualitatively similar to a Lead I ECG. The WHOOP ECG Feature determines the presence of atrial fibrillation (AFib), normal sinus rhythm, low heart rate (≤ 50 beats per minute [bpm]), and high heart rate (≥ 100 bpm) on a classifiable waveform. The WHOOP ECG Feature is not recommended for users with other known arrhythmias.
The WHOOP ECG Feature is intended for over-the-counter (OTC) use. The ECG data displayed by the ECG Feature are intended for informational use only. The user is not intended to interpret or take clinical action based on the device output without the consultation of a qualified healthcare professional. The ECG waveform is meant to supplement rhythm classification for the purposes of discriminating AFib from normal sinus rhythm and is not intended to replace traditional methods of diagnosis or treatment.
The WHOOP ECG Feature is intended for use by adults 22 years of age and older.”
Whoop hired Anthony Owusu for this position in September 2021. Owusu spent 2.5 years at Whoop leading its regulatory affairs efforts before he left to join Meta/Facebook as its head of medical devices quality management systems and compliance in February 2024.
Before Owusu left, Whoop hired Nikki Batista as its VP of Digital Health. Batista previously worked at IQVIA company MCRA as the VP of digital health regulatory affairs. Prior to that she was at the FDA working in the division focused on cardiovascular devices. Batista left Whoop in November 2024 — soon after the 510(k) was submitted — and opened her own consulting practice in January.
Before Batista left, Whoop hired Shweta Parwe (from Teva Pharmaceuticals) to lead regulatory affairs. Pawre is still at Whoop and is currently hiring for another regulatory affairs position. That job post makes clear (if the fact that Whoop already has full-time people focused on FDA clearances and compliance) that Whoop is planning to pursue additional 510(k)s. Note the plural — “SAMDs”:
“As the Quality Systems & Regulatory Affairs Specialist, you will execute regulatory strategy and support QMS maintenance deliverables for WHOOP SAMDs in a dynamic and agile environment.”
Given Whoop’s first FDA clearance mirrors Apple’s early FDA strategy, it’s worth reviewing which other SaMDs Apple has secured 510(k)s for over the years:
Irregular Rhythm Notification Feature: Apple has two 510(k)s and a de novo for a feature that alerts users when their heart rhythm is irregular. This feature makes the ECG app more actionable.
Sleep Apnea Notification Feature: Apple secured this 510(k) in September 2024. Given Whoop’s focus on sleep quality, I would expect a clearance similar to this one to be high on its list.
Apple also has 510(k)s for AFib history and digital prism correction (which is just for its Apple Vision Pro vr headset). It has a de novo clearance focused on its hearing aid tech too.
Here’s why I think Whoop is about to secure its second 510(k) clearance: The company actually completed its clinical trial for an abnormal rhythm notification feature months before it completed its clinical trial for its ECG sensing feature. Whoop worked with Yale University researchers and ZS Associates to conduct the notification feature study:
“The purpose of this protocol is to assess the sensitivity and specificity of a photoplethysmography (PPG)-based algorithm for the detection of atrial fibrillation as compared to a gold-standard assessment (wearable ECG patch) among a population of individuals with known atrial fibrillation and without known atrial fibrillation over a 7-day study period.”
There’s a good chance that Whoop hasn’t announced its first 510(k) clearance yet because it is waiting on this notification feature clearance to come through first. Apple announced both of those at the same time when it launched these features for the Apple Watch back in 2018.
Natural Cycles makes a puzzling move in its latest 510(k) — from OTC only to Rx+OTC
Last week I noted that the FDA posted a new 510(k) for birth control app, Natural Cycles. Since there was no summary document yet, I wondered if the clearance was for yet another body temperature sensing input device. NC currently works with Oura rings and Apple Watches so I figured maybe this was about adding a Samsung wearable. Well, the summary document was posted this week and the 510(k) is not focused on a new data input — it is making clear that Natural Cycles is both an over the counter device and a prescription device. Prior to this clearance NC was just an OTC device.
Moving from Rx-only to Rx and OTC is fairly common in the medical device world, but going the other way is odd.
I asked longtime digital health regulatory expert M. Jason Brooke, Attorney & Managing Member, Brooke & Associates why a company would submit a 510(k) to make that change.
“You are correct that it’s very uncommon to add Rx to an OTC device. A device that requires a prescription is one that requires clinician oversight to ensure its safe and effective use. An OTC device, on the other hand, is one for which the FDA has determined that the lay user is adequately capable of self-identifying as an appropriate user and self-selecting the device as appropriate for their condition without the input or oversight of a clinician. If a device is already cleared to be OTC, the device inherently does not require clinician oversight for its safe and effective use, so it would not make much sense to include or add the Rx limitation on an OTC product.”
Brooke speculated that there were a few scenarios where it might make sense:
“A few reasons come to mind as to why a company might add the Rx when it already has OTC status:
- the product might have two versions with different features, some of which require Rx to be used safely and effectively;
- some states might require the product to be prescribed by a clinician under the state practice of medicine laws; and
- the product might need to be prescribed in order to facilitate certain reimbursement for the clinician. The FDA doesn’t really get involved in [number two] or [number three] but I could see a scenario where the company conveys their reasoning for adding Rx to the FDA and the agency doesn’t push back.
On this 510(k) in particular, it’s interesting that they described the addition of Rx use as not raising different questions of safety and effectiveness to justify that a 510(k) is appropriate. There are inherent differences in the risk profiles of an Rx device and OTC device (as noted above) so to say that adding Rx doesn’t raise new questions of safety or effectiveness would suggest that the Rx label is not required–meaning that the device is effectively just an OTC device. The company notes that ‘[n]o changes have been made to the device technology, meaning there are no differences between’ the subject device and the predicate device. Given that, reason [number one] above wouldn’t apply here.”
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