Una revisión de idea real, completa

Disclosure first: my search tool hit its usage limit before returning any results, so I could not verify a single external source in this session. Everything below that is not from your brief is labelled as an assumption drawn from prior knowledge, and every number I give needs to be re-checked by you. Treat this as a structured list of demand questions with my priors attached, not as evidence.

The problem itself is almost certainly real, and that is the weakest part of your case, not the strongest.
Mid-treatment dropout in outpatient physio is one of the most heavily marketed pain points in the sector. My strong prior is that a whole product category already exists around it: WebPT Reach (which grew out of WebPT's acquisition of Strive Labs, a PT-specific patient-relationship/reactivation tool), Clinicient's acquisition of Keet Health, and horizontal patient-messaging vendors — Weave, Solutionreach, NexHealth, Podium, Birdeye — that all sell "reactivation campaigns" to small healthcare practices. If that is right, the demand question is settled and irrelevant: people do pay for this. The live question becomes why a standalone $99 tool wins against products already installed, which is a competitive question dressed as a demand question.

So the finding is not "nobody sells this." It is "several people sell this, and mostly bundled." That is a materially worse position than an empty market. An empty market can be a gap. A market where the feature is being given away inside the practice-management system or inside a $300/month messaging suite means your buyer's decision is not "$99 vs nothing" but "$99 vs a checkbox I already pay for."

Your price is anchored badly against the software the clinic already buys. My prior is that Cliniko sits roughly in the £/$45–200 per month range depending on practitioner count, and Jane App in the ~$80–150 range for a small clinic. If so, you are asking a 2–6 therapist clinic to pay roughly as much for one feature as it pays for its entire clinical record, booking, and billing system. That comparison will be made out loud in every sales call. It does not make $99 impossible, but it means the ROI argument must be shown in the clinic's own numbers within the first meeting, not asserted.

The ROI arithmetic is the reason this idea keeps getting built — and the reason it keeps churning. One recovered patient at ~4 remaining visits × $80–120 is $320–480, i.e. three to five months of your fee, from one save. Every vendor in this space uses that pitch. The fact that clinics still churn off such tools suggests the constraint is not the maths, it is that recovered-patient attribution is unprovable to the clinic owner (would they have rebooked anyway?) and that the SMS still requires a human to answer the reply and find a slot. You are selling into a front desk you have described as having no time — which is also the reason the tool underperforms after month two.

Distribution economics are the part I would stress-test hardest. $99/month is ~$1,188 a year per clinic. To clear $100k gross you need roughly 85–100 paying clinics, and with churn of even 3%/month you need continuous new sales forever. Independent clinics are owner-decided, slow, low-trust, and geographically scattered. There is no cheap channel: no dominant subreddit, no single conference that reaches them all, and paid search on terms like "physio patient reactivation software" is contested by well-funded incumbents. Your co-founder's three years on a front desk gives credibility in the room but does not give you a way to get into 100 rooms on evenings and weekends.

A hidden demand-killer: data access. Demand only converts if you can read the clinic's appointment data. My prior is that Cliniko and Nookal have usable public APIs, that Jane App's third-party API access has historically been limited or partner-gated, and that WebPT is effectively closed to outside vendors. If the systems your target clinics actually use won't let you in, a clinic that wants your product still cannot buy it. Check this before anything else — it can kill the business independently of whether anyone wants it.

Compliance is a purchase blocker, not just a legal chore. Outbound SMS to lapsed patients about rebooking sits near the marketing/treatment line. In the US that means TCPA consent questions plus a HIPAA BAA that a two-person evening project must be able to sign; in the UK/EU it means PECR/GDPR and lawful basis. Clinic owners ask this in the first call. "We're pre-BAA" ends the call.

Bottom line on demand: the problem is real and money already moves for it, so I will not tell you the market is empty. But nothing you have told me, and nothing I could verify, shows that independent 2–6 therapist clinics will pay $99/month for a separate tool that does one thing their PMS or their existing messaging vendor arguably already does. That specific willingness to pay is the entire business and it is currently unevidenced.

The slot you want to occupy is already occupied, at three levels

Level 1 — free, inside the software the clinic already pays for. Jane App ships an Unscheduled Patient Report: <cite index="3-6,3-7">a report designed to make the clinic aware of which clients are not booking appointments into the future, or to recall which patients haven't yet booked a future visit</cite> (https://jane.app/guide/unscheduled-patient-report). Jane also sends SMS natively, though <cite index="3-14">SMS reminders are only available on its Legacy, Practice, or Thrive plans</cite>. Cliniko has a recalls feature too (https://help.cliniko.com/en/articles/1023943-recalling-patients). Your detection engine — "who stopped mid-course" — is a report that already exists and costs the clinic nothing. What you'd actually be selling is the automated send on top of it, which is a much thinner wedge than the pitch implies.

Level 2 — third-party apps doing exactly your product, already integrated. This is the part that should worry you most:

• Peptalkr (https://www.cliniko.com/connected-apps/peptalkr/) is a Cliniko connected app whose entire pitch is that <cite index="1-8,1-9">Cliniko's recalls are not automated — you mark patients manually and follow up by letter, text or phone — whereas Peptalkr's system automatically identifies them</cite>. They already segment patients at <cite index="4-13">7, 14, 30, 60, 90 and 180 day intervals plus 1 and 2 year recall segments</cite>, and they <cite index="4-19">tailor the system for a 60-day free trial with no strings attached</cite>. That is your positioning, your trigger logic, and a free trial longer than most of your sales cycle.
• Routiq (https://www.routiq.ai/vs/peptalkr) sells lapsed-patient re-engagement with a compliance layer, describing Peptalkr as <cite index="4-8">the established Cliniko messaging specialist in Australia</cite> — i.e. the category already has a comparison-page war going on.
• Cliniko's own connected-apps directory (https://www.cliniko.com/connected-apps/) lists DataFlows, which <cite index="2-2">automates patient SMS from Cliniko: reminders, AI-handled replies written back to Cliniko, recalls, follow-ups and bulk campaigns, set up in under five minutes</cite>, and another app pitching <cite index="2-4">automatically re-engaging inactive patients</cite>.
• Cliniq Apps (https://www.cliniqapps.com/) markets AI SMS to physio/podiatry/speech clinics.
• My AI Front Desk (https://www.myaifrontdesk.com/therapy/jane-app-ai-integration) advertises <cite index="3-1">voice and HIPAA SMS to reactivate lapsed clients in SimplePractice, TherapyNotes, Jane App and others</cite>.

Level 3 — the platform players who bundle it. WebPT Reach is PT-specific and explicitly retention/reactivation: <cite index="0-3">a fully integrated platform for rehab therapy providers to design and implement patient engagement, retention, reactivation and referral campaigns</cite>, sold in <cite index="0-2">three product tiers</cite> (https://www.webpt.com/products/reach). Pabau runs a physiotherapy vertical page and publishes a "best patient reactivation software" listicle (https://pabau.com/blog/patient-reactivation-software/) — when incumbents write the category listicle, the category is mature, not empty. Weave starts <cite index="7-20">from $199 per month</cite> (https://www.getweave.com/pricing/) and <cite index="7-0">Podium's core plan starts at $399 per month</cite>. One vendor blog claims <cite index="7-13">Clinic OS Pro is a $149 per month retention engine built specifically for small PT clinics</cite> — treat that source as self-promotional, but a named, cheap, PT-specific retention product is exactly the competitor you'd rather not find.

The distribution wall, which is a competitive fact not a technical detail

Jane deliberately does not have an open API: <cite index="3-17,3-18,3-19">they state they're not launching an open, public API where any product can connect to Jane, and are instead building a vetted partnership pathway with an intake and approval process before partners can connect</cite> (https://jane.app/blog/jane-integrations-our-program-our-partners-and-how-to-work-with-us). Jane is one of the dominant systems for independent allied-health clinics. So a two-founder evenings-and-weekends team with under $5,000 is realistically limited at the start to Cliniko's open API — which is precisely the directory where Peptalkr, DataFlows and the AI reactivation apps are already sitting, with a listing you'd have to earn and they already have.

The competitor nobody lists: the front desk booking the whole course up front

The zero-cost substitute for your product is a clinical/ops habit — book the full plan of care at visit one and rebook at the desk before the patient leaves. It prevents the dropout rather than chasing it, and every physio business coach sells that script for free in a blog post. Your own problem statement ("front-desk staff have no time to chase them") describes a clinic that hasn't implemented the free fix. A clinic that won't run a two-minute desk habit is not obviously a clinic that will configure, monitor and act on an SMS automation. That's an adverse-selection problem in your target segment, not a market.

What would have to be true for a switch

Be honest about what the buyer is actually deciding. They have exactly one mental slot for "the thing that texts our lapsed patients". If it's filled, switching costs them: re-consenting the patient list, re-doing templates, changing the SMS sender ID their patients recognise, a new data-processing agreement, and re-training the receptionist. None of that is worth doing for a product that is better at the same job. Realistic switch triggers, none of which "simpler and cheaper" satisfies:

1. Their PMS isn't supported by the incumbent (this is your only real opening — a system Peptalkr/Routiq/WebPT don't cover, e.g. a UK stack like PPS, WriteUpp or TM3, if you can confirm the gap).
2. The incumbent is bundled into a phone-system contract they want out of anyway (Weave/Podium at $199–$399/mo have real switching resentment).
3. A compliance event — the incumbent sent something that breached local advertising or consent rules. Note Routiq already sells compliance checking as a differentiator, so the compliance flank is being defended.
4. You are billed as a service outcome (revenue recovered) rather than a tool, in which case you're competing with marketing agencies, not software, and $99/mo is the wrong price.

The price point works against you competitively

$99/mo is in the dead zone: too high to be an impulse add-on next to a PMS subscription in a similar range, too low to fund the human onboarding that would actually differentiate you from a self-serve app in the Cliniko directory, and too low to justify the sales effort of prising a clinic off Weave. It also gives you no room to absorb SMS carrier costs, which are per-message and rise with exactly the usage that makes the product look successful.

What the founder advantage is worth here

Three years on a front desk is a credibility asset for getting meetings and for writing message copy that doesn't read like spam. It is not a competitive moat against Peptalkr's trigger library or WebPT's EMR bundling, and it does not solve the Jane API problem.

What actually has to exist

This is not "an SMS sender". To ship anything a clinic will pay for, you need six pieces, and four of them depend on other people cooperating:

1. A read integration with the clinic's practice management system (PMS) — appointments, patients, phone numbers, future bookings, and ideally treatment-plan/discharge status.
2. Dropout detection logic that survives contact with real data.
3. Messaging infrastructure with per-clinic sender registration (US 10DLC brand + campaign, or toll-free verification; UK/AU alphanumeric or long code).
4. A reply path. Patients will answer the text. Someone has to read "can I do Thursday?" — either you build an inbox, or you forward to the clinic, or replies vanish and the clinic blames you.
5. Consent, opt-out and audit records — STOP handling, quiet hours, per-patient suppression, proof of who consented when.
6. Contracts: BAA (US), DPA (UK/EU/AU), plus your own terms allocating TCPA/PECR/Spam Act liability.

The parts most likely to be underestimated

Integration gating is the single biggest binary risk. Cliniko and Nookal publish developer APIs; WriteUpp and PPS have partner routes. Jane App — very common among physios in Canada/US/AU — has historically had no open public write/read API for third parties, only a partner programme. US clinics running WebPT, Prompt, Raintree or Clinicient are effectively enterprise sales with gated API access, or you pay an aggregator like NexHealth (list pricing I've seen quoted is in the hundreds to low thousands per month, which annihilates a $99 price point). Before writing a line of code, find out what your first 20 target clinics actually run. If more than half run Jane or a gated US EMR, the product cannot be built at this price.

"Stopped part-way through a course of treatment" is probably not in the API. Most PMS APIs give you appointments and patients. The plan of care ("6 sessions over 4 weeks") usually lives in free-text clinical notes, which are often either not exposed or exposed under stricter permissions. In practice your detection will be a heuristic: last appointment >N days ago, no future booking, fewer than M visits in the episode. That will fire on patients who were discharged, who recovered, who moved, who died, and who left because they disliked the therapist. Your clinical co-founder can tune it, but the false-positive rate is your product quality and you cannot measure it until you have live clinics.

Sender registration is per-clinic manual work. In the US, an ISV reseller model means registering each clinic as a secondary brand (EIN, legal name, address) plus a campaign, with vetting, sample messages and a lead time of days. Rejections happen. That is 30–90 minutes of your time per clinic, repeated, and it blocks activation. Toll-free verification is a similar queue. Budget this as a recurring onboarding cost, not a one-off.

TCPA (US) is the compliance item that can end the business, not HIPAA. HIPAA treats appointment/treatment communications reasonably permissively and Twilio will sign a BAA. TCPA does not care about that: a text nudging someone to book is arguably marketing, statutory damages are $500–$1,500 per message, and plaintiff firms actively troll healthcare SMS. Your defence is the clinic's prior express written consent — which you have to trust the clinic collected, and which their intake form probably doesn't cover for marketing. Your contract can indemnify you on paper; a small LLC with 40 customers being sued alongside its customer still dies. UK/EU (PECR soft opt-in, existing-patient relationship) and Australia (Spam Act, inferred consent) are materially softer. Feasibility improves a lot if you start UK/AU/NZ, which also happens to be where Cliniko and Nookal dominate.

Support load vs $99 ARPU. At $99/month with ~$10–20/month of Twilio and infra COGS per clinic, you have roughly $80 of gross margin. One 45-minute support call, one "why did Mrs Patel get this text" escalation, or one 10DLC rejection wipes out a month. Fifty clinics at $99 is $4,950 MRR — a side income, and enough inbound to consume most of two people's evenings. The business only works if onboarding is under ~2 hours and steady-state support is under ~10 minutes per clinic per month. That is achievable, but only after several iterations you cannot afford to skip.

Incumbent overlap. Cliniko has recalls and SMS reminders built in; Jane has recall/unbooked-patient features; Weave, Solutionreach, RevenueWell and Podium sell reactivation as part of a larger bundle at higher prices. The detection heuristic is the only defensible piece and it is a weekend of work for a PMS vendor. Verify exactly what your target PMS already ships, because "we already have that" from the vendor is a common way this category dies.

Money and time, concretely

• Build to first paying clinic: with two part-time founders, one integration, 10DLC, a reply inbox and a minimal dashboard — realistically 4–7 months of evenings. A 6-week estimate is wrong.
• Cash before revenue: hosting $20–60/mo; Twilio numbers ~$1.15/mo each + campaign fees; SMS ~$0.008–0.011/segment + carrier surcharges; legal for BAA/DPA/terms with a TCPA-literate lawyer $1,500–4,000; E&O + cyber insurance $1,000–2,500/yr; company + ICO registration trivial. Your $5,000 covers infrastructure comfortably and legal or insurance, not both, and leaves nothing for a design or a Cliniko partner listing push.
• Ongoing per month at 30 clinics: infra $100–200, Twilio $300–600, insurance ~$150, plus the real cost — the hours. Assume 15–25 hours/month of support and onboarding at that size.

What would make this feasible

Start in one country, one PMS with a documented public API (Cliniko is the obvious candidate), one message template, replies forwarded to the clinic's existing email/phone rather than a built inbox, and manual onboarding you do yourself. If you cannot get 5 clinics to hand you API keys before you build, the integration question is moot.

The structural problem on this angle, stated first

Your buyer is reachable between roughly 8am and 6pm on weekdays. You are available evenings and weekends. Independent physio clinics do not have a night shift; the owner-principal is treating patients all day and the front desk goes home. Every direct route to the first fifty customers — cold calls, walk-ins, discovery calls, live demos, onboarding, support during a trial — sits inside hours you have said you do not have. This is not a motivation problem you can grind through. Until one of you can be on the phone during clinic hours, or you can get an intermediary who is already in front of these owners to do the talking for you, the acquisition plan does not have a mechanism. Address this explicitly before anything else.

The $99 price does not fund a distribution channel

$99/month is $1,188 a year gross. Strip SMS costs, Stripe, and support and call it $850–$950 contribution. Assume SMB churn of 3–5%/month (my assumption, verify against your own cohort) and lifetime value lands somewhere near $1,500–$2,500. That number has to cover acquisition, a free trial, and any affiliate or reseller cut.

Run it against the one channel where your buyers demonstrably gather in bulk: <cite index="7-1,7-4">the APTA Private Practice Annual Conference & Exhibition, whose exhibit hall "sells out every year" and where booths "sell out quickly"</cite>. Booth plus travel plus stand for two people is, on my assumption, $8,000–$15,000 — two to three times your entire budget — and a first-time unknown vendor at that show should not expect more than a handful of closed accounts. That is a CAC in the high hundreds against an LTV under $2,500, before you have built anything. The same arithmetic kills Google Ads and Meta Ads for this niche. At $99 you can afford exactly one channel: founder-led sales. Which returns you to the hours problem.

Where these people actually gather, named

• The clinic-business coaching ecosystem. This is the single highest-yield route and the only one I can see delivering 50 then 500. Businesses like Clinic Mastery, Breakthrough PT Marketing, and the various "PT owners" mastermind programmes already hold paying cohorts of clinic owners, already teach plan-of-care completion and retention as a KPI, and already have permission to recommend tools. You are not selling to a clinic; you are selling to a coach who will put you in front of 80 owners on a Zoom call. Cost of entry is a revenue share, not cash. Go and get three of these conversations before you write a line of code.
• Practice-management software directories. <cite index="3-4">Cliniko publishes a "connected apps" page for third-party integrations</cite> and <cite index="11-3">issues user-generated API keys that grant an application access to a clinic's Cliniko data</cite> — so a Cliniko-first build is technically open to you and the directory listing is a real, free, intent-qualified channel. Jane is not: <cite index="2-2">Jane has stated it is "not launching an open, public API where any product can connect" and is instead building a vetted partnership pathway</cite>, with <cite index="5-1">documentation restricted to partners already approved into the programme</cite> and <cite index="2-4">selection influenced by "community interest and partner support"</cite>. Practically: Cliniko and Nookal give you a route in months; Jane is a gate you may not get through, and it holds a large share of the allied-health clinics you are targeting.
• Association directories as list sources, not as channels: APTA's Find a PT, Physio First's member directory in the UK, the APA's Find a Physio in Australia. These give you names and phone numbers for a cold-call list; they do not give you distribution.
• Owner-focused Facebook groups and r/physicaltherapy. Assume these are closed to you as a vendor. Most are either run by a competing agency or ban promotion outright, and the ones that don't are already saturated. Being a member who answers front-desk questions for six months is a real strategy; posting a launch is not.

The channel is occupied by the platforms you would depend on

This is a distribution problem, not just a product one: the incumbents are marketing your feature as a reason to stay inside their suite. <cite index="8-1,8-2">Pabau positions reactivation as configurable by last visit date with outreach by SMS or email and explicitly markets "no separate plan, no third-party sync, and no data mapping required"</cite>. <cite index="9-1">Mindbody markets plan-of-care and reactivation campaigns as built-in SMS/email automation</cite>. <cite index="10-2">PT Everywhere markets drip series "segmented by diagnosis, stage, or last-visit date - ideal for reactivation"</cite>. <cite index="1-1">Podium already integrates with Cliniko to sync contacts and send automated status-based messaging</cite>. Your sales conversation therefore does not start at "here is a problem you didn't know about" — it starts at "why not just use the thing already in my software". Your answer has to be a number, and you do not have one yet.

The route I would actually run for the first fifty

Not software. A manual reactivation audit. Get read-only Cliniko/Nookal access from five clinics your clinical founder can reach personally, pull the appointment history, and hand back a one-page report: "214 patients stopped after visit two in the last six months; at your average of $X per visit and an average course of six, that is $Y of unfinished care sitting in your database." Then text them by hand for a month and report the recovered dollars. That report is your entire sales asset. It converts because it is about their money, it can be produced in an evening, and it doubles as the proof you need for every channel above. Fifty customers comes from repeating that audit — via coach introductions and referrals from the first five — not from a launch.

The next five hundred is where I cannot see a route at $99. Coach cohorts run out. The Cliniko directory is passive and small. Conferences don't pay back. If the answer to 51–500 is "more founder calls", the business tops out somewhere around $10–15k MRR and stays there, which is a decent side income and not something to fund with savings at the current price.

One acquisition-blocking objection you will hit in every demo

"Am I allowed to text patients who stopped coming?" A rebooking prompt to a lapsed patient is closer to marketing than to an appointment reminder, and the consent they gave for reminders may not cover it. In the US this collides with A2P 10DLC: <cite index="14-2">campaign registration requires message samples and proof that consumers opted in</cite>, <cite index="15-1">traffic stays blocked until numbers are linked to an approved campaign</cite>, and <cite index="13-1">healthcare senders carry sector content rules on top</cite>. You need a rehearsed, jurisdiction-specific answer with a lawyer's name behind it, or your close rate dies at the objection stage regardless of how good the channel is.

The most likely story, 18 months from now

Failure mode 1 — you never got clean write access to the practice management system, and the manual version wasn't worth $99.

The entire value of this product is that it happens without the front desk doing anything. That requires reading appointment/treatment-plan data out of the clinic's PMS and ideally writing bookings back. In physio, that means Jane App, Cliniko, Nookal, WriteUpp, Physitrack/PracticeHub, WebPT, Raintree — a fragmented list where you must build and maintain one integration per system, each gated by someone else's partner-approval decision. Cliniko and Nookal have public APIs; Jane's API access has historically been restricted and partner-approved rather than open self-serve (verify this yourself — it is the single most important fact in your whole plan, because Jane is very widely used by independent physio/chiro clinics in North America). If your first ten interested clinics are on a PMS that won't let you in, the project is over before you write code.

The fallback — CSV export, or the clinic pastes a list in — degrades the product from "automatic revenue recovery" to "another dashboard someone has to remember to open." That is the same behavioural problem you identified in the clinic. Software that produces a list of lapsed patients does not fix an organisation where nobody has time to work the list.

Failure mode 2 — the unit economics never let two part-time founders reach escape velocity.

$99/mo = $1,188 ARR per clinic. Split between two people working evenings, with under $5,000. To clear even $10k MRR you need ~100 clinics; realistic SMB churn of 3–5%/month means you're replacing 3–5 of them every month just to stand still. Selling to independent clinic owners is one-at-a-time, phone-and-demo work — there is no cheap self-serve channel for a product that requires PMS credentials and a compliance conversation. Paid acquisition at this ACV is arithmetically dead. So the plan implicitly depends on founder-led sales at maybe 2–5 closes a month in whatever hours are left after day jobs. Eighteen months of that is perhaps 30–50 customers, ~$4k MRR gross, before SMS costs, before churn, before the two of you split it. That is a decent side income, not a business you'd fund with savings.

The $99 price also fights itself: if the product genuinely recovers even two patients a month at $70–$90 a visit, it's worth far more than $99, and you've priced away the margin you'd need to pay for sales. If it doesn't recover two patients a month, the clinic cancels.

Other things that will bite

• This category already exists. "Patient reactivation" is a standard product line in dental and chiro, and in physio specifically WebPT sells Reach as a patient re-engagement/marketing product. Weave, Podium, Solutionreach, NexHealth and RepeatMD-style vendors all sell reactivation campaigns into allied health at $300–500/mo. You'd be the cheap unbundled version of a feature several funded companies already ship. Verify these claims, but assume you are not first.
• Platform risk is existential, not theoretical. Cliniko already has recall functionality; Jane has waitlist and follow-up tooling. A single feature release by the PMS you integrate with — the same company whose API approval you depend on — makes you free and redundant. You are building a feature on someone else's roadmap, with their permission.
• SMS compliance eats the margin and the onboarding. In the US you need A2P 10DLC brand + campaign registration per sending brand (one-off vetting fees plus per-campaign monthly carrier fees), TCPA exposure at $500–$1,500 statutory damages per message for consent failures, and a HIPAA BAA because you're processing PHI. In the UK, PECR consent/soft opt-in rules plus UK GDPR. In Australia, Spam Act plus AHPRA advertising rules on practitioner marketing. At $99/mo, a 45-minute compliance onboarding per clinic is most of your first-year gross margin, and the first clinic that gets a complaint will ask you to indemnify them.
• Attribution will be contested. Some share of lapsed patients stopped because they got better, moved, or didn't like the therapist. When the clinic asks "how many of these would have rebooked anyway?", you have no honest answer without holdout groups, which you won't run at 30 customers. Churn follows.
• The stated advantage is insight, not distribution. Three years on a front desk tells you what to build. It does not tell you how to reach 300 clinic owners. If neither founder has a warm list of 100+ clinic owners or an existing audience, sales is a cold-start problem you have not budgeted for.

What depends on luck, timing, or someone else

• Jane/Cliniko/Nookal granting and keeping API access — someone else's decision, revocable.
• Those same vendors not shipping this natively — pure timing luck.
• Carrier/10DLC campaign approval for a healthcare-adjacent messaging use case — someone else's decision.
• Finding a design-partner clinic willing to hand you patient data before you have a product or a DPA/BAA — luck plus trust.
• Whether the geography you're in has permissive marketing-consent rules for lapsed patients — regulator's decision, not yours.

You were not specific about country, target PMS, or whether either founder has a sales list. Those three unknowns determine whether this is merely hard or actually blocked, and none of them are things I can resolve for you.