Two-phase development is a startup strategy, not just a regulatory tactic. Phase 1 is the exploratory work that proves the product is worth building at all — the market verification, the technology feasibility, the workflow reality check. Phase 2 is the committed, compliant build that turns a proven idea into a certifiable medical device under Regulation (EU) 2017/745. The two phases have different tempos, different risks, different investors, and different founder psychology. Startups that treat them as one continuous project burn runway on the wrong work at the wrong time. Startups that run them deliberately — with a clean design freeze between them — ship.

By Felix Lenhard and Tibor Zechmeister. Last updated 10 April 2026.

TL;DR

  • Two-phase development is most often written about as a regulatory tactic — a way to avoid over-documenting prototypes. Seen from the founder's seat, it is first and foremost a capital strategy and a business strategy.
  • Phase 1 answers the question "is this worth building?" Phase 2 answers the question "can we build it the way the Regulation requires?" The two questions cost radically different amounts of money and take radically different kinds of courage.
  • The design freeze between the phases is a business decision as much as a technical one. Frozen too early, the company commits capital to the wrong product. Frozen too late, the company stays exploratory forever and runs out of runway.
  • Investors read Phase 1 and Phase 2 differently. Phase 1 is a seed-stage bet on a team and a hypothesis. Phase 2 is a Series A bet on execution against a known regulatory and clinical target. Confusing the two in a pitch is how founders get turned down.
  • The most common founder mistakes are starting Phase 2 before the market is verified, dragging Phase 1 into permanent exploration, and treating the design freeze as a paperwork event instead of a governance decision.

A founder's view of the two phases

Most discussion of two-phase development in MedTech starts from the regulatory side: what documentation must you produce, what counts as placing a device on the market, where does MDR Article 10(9) obligation begin. That conversation is covered in depth in the regulatory-angle companion post. This post takes the other seat at the table — the founder's seat — and asks what the two phases mean for capital, for team, for time, and for the set of decisions that keep the company alive.

From the founder's perspective, Phase 1 and Phase 2 are not mainly about paperwork. They are two different kinds of business. Phase 1 is an exploration business. You are buying information. Every euro you spend is meant to reduce uncertainty — about the technology, about the buyer, about the workflow, about whether the problem is real. Phase 2 is a construction business. You are buying a certified product. Every euro you spend is meant to convert a frozen design into something a Notified Body will accept.

Those are not the same skills. They are not the same team. They do not attract the same investors. They do not reward the same founder habits. Running them with the same mindset is one of the most common reasons MedTech startups burn through runway without shipping.

A founder Felix worked with spent EUR 1.8 million on a device that was beautiful in a lab and broke the moment a real clinician picked it up in a real ward. The money was spent in what looked like Phase 2 — engineering, iteration, polish. It should have been Phase 1 — shadowing real users in the real setting, discovering the workflow gap, deciding whether to pivot, cut, or push through. The company had collapsed the two phases into one long construction project and skipped the exploration business entirely. That is the failure mode this post exists to prevent.

Phase 1 from the founder's perspective — the commercial risks

Phase 1 looks cheap from the outside. No full QMS, no technical file, no Notified Body contract, no clinical investigation budget. Founders who learn about two-phase development sometimes walk away thinking Phase 1 is the easy part. It is not. It is where the company's most expensive mistakes are actually made, because the mistakes compound silently and only surface once Phase 2 is underway.

The first commercial risk in Phase 1 is the risk of verifying the wrong thing. Founders in Phase 1 tend to run the technology track and neglect the market track. They build prototypes. They run bench tests. They refine algorithms. All of it feels like progress. None of it answers the questions that matter to a hospital buyer, a practising clinician, or a patient. When Phase 2 begins, the company discovers that the thing they verified is not the thing the market wants, and the cost of pivoting has gone up by an order of magnitude because the design is now partly frozen.

The second commercial risk is Phase 1 eternal. A founder who loves building and hates commitment will iterate forever. Every week produces a slightly better prototype, a slightly sharper demo, a slightly refined pitch. Nothing ever freezes. The runway runs out in a long, slow exhale, with a founder who can honestly say they never stopped working. Felix has watched this in at least one founder he begged for eighteen months to go out and talk to customers. The founder did nothing — no customer conversations, no letters of intent, no revenue, no clinical partners — for eighteen consecutive months. The company dissolved. It was not Phase 2 that killed it. It was a Phase 1 that never ended.

The third commercial risk is the silent ethics drift. Phase 1 is where founders are tempted to "just let a friendly doctor try it." Not a clinical investigation, not an ethics-approved study — a favour. This is not a corner to cut. It is a legal red line and a career-ending decision. Phase 1 stays inside research and ethics-approved boundaries, or it stops being Phase 1.

The fourth commercial risk is failing to capture what Phase 1 actually learns. Phase 1 does not require a full QMS, but it does require discipline. The decisions made in Phase 1 — why this architecture, why this patient population, why this workflow, why this intended purpose — become the input to the Phase 2 technical documentation. Founders who treat Phase 1 as a free-for-all and then cannot reconstruct their own reasoning in Phase 2 lose months rebuilding what they already knew.

Phase 2 from the founder's perspective — the commercial advantages

If Phase 1 is risky in invisible ways, Phase 2 is risky in visible ones. The costs are large and obvious — EN ISO 13485 QMS build, technical documentation to Annex II, clinical evaluation, Notified Body fees, PRRC, usability engineering, cybersecurity. The calendar is long. The audit is real. Founders looking at Phase 2 often see only the weight.

The weight is there. What is less often discussed is the commercial advantage that comes with crossing into Phase 2 correctly.

A company in Phase 2 is a different kind of asset. The product exists, the design is frozen, the intended purpose is sharp, the classification is settled, the regulatory route is known, and the path to CE marking can be costed and scheduled. All of that is legible to a sophisticated MedTech investor in a way that a Phase 1 company is not. A founder who walks into a Series A with a Phase 2 company can answer the questions that matter — what does it cost from here, how long does it take, what are the specific risks on the critical path — with numbers rather than hand-waving.

A company in Phase 2 also has a team shape that looks right. Phase 1 is usually a small, generalist, exploratory team. Phase 2 needs QA, regulatory, clinical, software lifecycle, verification and validation, PMS planning. The team build-out in early Phase 2 is one of the most meaningful proof points a founder can show an investor. It signals that the company has committed to the construction business and knows what that business requires.

A company in Phase 2 also has leverage with clinical partners that a Phase 1 company does not. Clinical partners who were courted in Phase 1 can now be converted into investigation sites. Letters of intent collected in Phase 1 can be converted into first purchase orders. The commercial machine assembled in Phase 1 starts to turn in Phase 2.

None of this happens automatically. The Phase 2 commercial advantage is available only to founders who entered Phase 2 deliberately, with the market already verified and the design ready to freeze. Founders who fall into Phase 2 by accident — because they felt they should, or because an investor pushed them, or because they were bored of exploring — inherit the weight without the leverage.

The design freeze as a business decision

The transition between the phases is not a regulatory stamp. It is a governance decision. Founders often frame it as a technical milestone ("the prototype works") or a documentation event ("we started the QMS"). Both framings miss the point. The design freeze is the moment the company commits the majority of its remaining capital to a specific product, for a specific intended purpose, for a specific buyer and clinical setting, over a twelve to twenty-four month horizon. It is the single largest allocation decision in the company's early life.

A competent design freeze is made when three business conditions are simultaneously true. The first is that the market is verified in enough depth that the founder could defend the buyer, the user, the clinical benefit, and the pricing in front of a sceptical board. The second is that the technology is proven enough that the founder would personally bet their own money on the device working in the real world, not the lab world. The third is that the financial model supports the cost of Phase 2 — with honest numbers on development, certification, PMS, team build-out, and working capital — and still ends up profitable at a reasonable unit volume.

When those three conditions are met, the design freeze becomes a business milestone worth celebrating. When they are not, the design freeze is a decision to spend money against unverified assumptions, and the founder should either resist the pressure to freeze or go back and verify what is missing.

The hardest version of this decision is the one where the technology is clearly working but the market is not clearly verified. Founders in this situation are tempted to freeze the design because the engineering is ready. They should not. Phase 2 against a verified technology and an unverified market is the fastest way to burn a Series A.

How investors react to each phase

Investors read Phase 1 companies and Phase 2 companies as two different asset classes, and founders who understand the distinction get better terms in both rounds.

Phase 1 is a seed-stage story. The pitch is about the team, the hypothesis, the market insight, the early clinical partners, and the specific experiments that will resolve the biggest risks. Investors at this stage are buying conviction in the founder's ability to navigate uncertainty. They expect the device not to exist yet in a frozen form. They do not want to see a full regulatory project plan — if they do, they will worry that the founder has committed capital before the learning is done. The right Phase 1 pitch shows discipline about what will be learned with the next tranche of capital, not a five-year regulatory Gantt chart.

Phase 2 is a Series A story. The pitch is about execution against a known target. The intended purpose is written down and stable. The classification is settled. The conformity assessment route is selected. The clinical evaluation strategy is defensible. The team build-out is planned. The cost and calendar to CE marking are specific numbers with ranges. Investors at this stage are buying execution capacity against a de-risked plan. They want to see the Phase 1 learnings carried into Phase 2 concretely, not paraphrased.

Founders get into trouble when they pitch Phase 1 as if it were Phase 2 — claiming certainty they do not have, promising calendar dates they cannot hit, showing regulatory plans that have no foundation in verified market reality. Equally, founders get into trouble when they pitch Phase 2 as if it were Phase 1 — sounding exploratory when the investor expects execution clarity.

The honest framing in both cases is the same: "We are in Phase [X], here is what we have verified, here is what we still need to verify, and here is the decision the next round of capital funds." Any investor worth taking money from understands this and will respect it more than false certainty.

Common founder missteps

The pattern of mistakes around two-phase development is small and repetitive. A founder with a strong regulatory partner can avoid almost all of them.

  • Starting Phase 2 on a lab-verified prototype. The prototype works in the founder's hands, in the founder's lab, with the founder's workflow. That is not verification. Phase 2 on a lab-only prototype produces the EUR 1.8 million failure pattern — a certified device nobody can actually use.
  • Treating the design freeze as a paperwork event. Founders sometimes "freeze" the design by writing it down in a document and then keep iterating informally. The regulatory trail and the engineering reality drift apart within weeks. The audit catches it eventually, and the correction is expensive.
  • Letting investor pressure set the phase boundary. An investor who wants to see "progress toward CE marking" can push a founder into Phase 2 before Phase 1 is complete. The right response is to reframe the investor question — progress toward CE marking is impossible before the design is freezable. Pushing into Phase 2 early does not accelerate CE marking. It delays it.
  • Keeping Phase 1 open as a comfort zone. Exploration is easier than commitment. Founders who prefer the open-ended nature of Phase 1 can rationalise staying there indefinitely. The symptom is an eighteen-month stretch with no new customer conversations, no letters of intent, no clinical partners advancing, and no team build-out. The cure is a hard external deadline tied to runway.
  • Running the two phases with the same team mindset. Phase 1 rewards generalists and fast iteration. Phase 2 rewards specialists and disciplined execution. Founders who do not shift the team mindset at the phase boundary get either chaos in Phase 2 or paralysis in Phase 1.
  • Forgetting that Phase 1 failures are the point. Phase 1 exists to kill bad ideas cheaply. A Phase 1 that produces a pivot, a scope cut, or a decision to stop is not a failed Phase 1. It is a successful one. The failure is only when Phase 1 money was spent and nothing was learned.

The Subtract to Ship angle

Two-phase development is the time-axis expression of the Subtract to Ship framework. Phase 1 subtracts every activity that does not reduce uncertainty about the product, the market, or the workflow. Phase 2 subtracts every activity that does not contribute to the technical documentation, the risk file, the clinical evaluation, or the QMS records a Notified Body will actually review.

The phase boundary is the single highest-leverage subtraction point in a MedTech company's early life. Before it, the question is always "what are we learning from this?" After it, the question is always "what article, annex, or standard does this trace to?" A founder who can answer both questions sharply at the boundary is a founder who has earned the right to spend Phase 2 capital.

Reality Check — Where do you stand?

  1. Can you state, in one sentence, whether you are currently in Phase 1 or Phase 2? If the answer is both, you are in neither, and your capital is at risk.
  2. Have you verified your market — buyer, user, patient, workflow, pricing — to the point where you would personally bet your own savings on the business model?
  3. Is your technology proven in the real setting, not the lab setting? Have you watched a real clinician use it in a real ward, with real interruptions and real time pressure?
  4. Is your intended purpose stable enough that it has not changed in the last sixty days? If it has, you are still in Phase 1 no matter what the engineering looks like.
  5. Do you have at least one clinical partner who would say yes to participating in a clinical investigation tomorrow if the device were ready?
  6. Have you costed Phase 2 honestly — QMS, technical documentation, clinical evaluation, Notified Body fees, PRRC, team build-out, working capital — and does your runway actually cover it?
  7. Does your current investor pitch match your current phase, or are you claiming Phase 2 execution clarity on top of Phase 1 exploration?
  8. Is there a specific decision-maker on the team who owns the design freeze call, and do they have the authority to say no to freezing early?

Frequently Asked Questions

Is two-phase development only relevant for regulated industries? No. The distinction between an exploration phase and a committed build phase is a general startup discipline. It shows up in consumer products, in enterprise software, in deep tech. MedTech makes the distinction louder because the cost of the committed build phase is so much larger and the regulatory consequences of freezing the wrong thing are so much more expensive, but the strategic logic applies anywhere capital commitment compounds with calendar time.

How do I know when I am ready to move from Phase 1 to Phase 2? When three business conditions are true at once. The market is verified in enough depth that you could defend the buyer, the user, the benefit, and the pricing in front of a sceptical board. The technology is proven in the real setting, not only the lab. The financial model supports the cost of Phase 2 and still produces a profitable business at a realistic unit volume. If any one of those is weak, stay in Phase 1.

What do I tell an investor who wants to see regulatory progress before market verification is done? Tell them the honest sequence. Market verification is the foundation that makes the regulatory project legible and fundable. Starting the regulatory project before market verification produces a regulatory plan built on guesses and wastes the money that could have been spent verifying the guesses. A sophisticated MedTech investor will understand this. An investor who does not is an investor whose money will burn before it helps you.

Can the two phases overlap? Some thinking overlaps. Light Phase 2 thinking — intended purpose drafts, classification hypothesis, regulatory route sketch — can start late in Phase 1 because it sharpens the questions Phase 1 is trying to answer. Heavy Phase 2 spending — QMS build, technical file, Notified Body contracts, formal clinical investigation under Annex XV — should wait until the design is actually ready to freeze. The rule is cheap overlap, not expensive overlap.

What if my investors are pushing me into Phase 2 before I think I am ready? Have the conversation before you take the money. Investors who understand MedTech will respect a founder who can explain why the design is not yet ready to freeze and what the next tranche of capital is actually funding. Investors who cannot have that conversation are the wrong investors for this company. Taking their money and spending it on a premature Phase 2 is one of the most expensive mistakes a MedTech founder can make, and it is usually irreversible.

How does two-phase development connect to product-market fit? Phase 1 is where product-market fit gets verified. Phase 2 is where the verified fit gets turned into a certified product. A founder who enters Phase 2 without verified product-market fit is building a compliant version of something nobody has said yes to. See product-market fit for MedTech startups for the full treatment of how MedTech PMF actually works.

Sources

  1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, consolidated text. Articles and annexes cited: Article 10(9) (quality management system obligation for manufacturers, with the exception for investigational devices); Annex II (technical documentation); Annex XV (clinical investigations — requirements for investigational devices). Official Journal L 117, 5.5.2017.
  2. Regulation (EU) 2023/607 of the European Parliament and of the Council of 15 March 2023 amending Regulations (EU) 2017/745 and (EU) 2017/746 as regards the transitional provisions for certain medical devices and in vitro diagnostic medical devices. Official Journal L 80, 20.3.2023.

This post is part of the MedTech Startup Strategy & PMF series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. Two-phase development is first a business strategy and only second a regulatory tactic. Get the phases right and the certification work gets tractable. Get them wrong and no amount of regulatory expertise will save the company.