Updated: December 13, 2025
Milestone Pharmaceuticals Inc. (Nasdaq: MIST) just crossed the line that separates “clinical-stage story stock” from “commercial execution stock.” Late Friday, the company announced FDA approval of CARDAMYST™ (etripamil)—a self-administered nasal spray for adults to convert acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm. [1]
And because markets love drama, MIST didn’t celebrate with a calm, rational repricing. Instead, the stock spent the week building into the decision, then delivered a violent rollercoaster session into Friday’s close—before the after-hours approval news hit. Now investors head into next week with a new reality: the regulatory question is answered, and the next debate is whether Milestone can launch, win reimbursement, and drive adoption fast enough to justify the expectations embedded in biotech land.
Below is the full “what happened / what it means / what to watch next” breakdown—built for readers tracking Milestone Pharmaceuticals stock, MIST stock news, and the CARDAMYST FDA approval catalyst.
The headline catalyst: FDA approves CARDAMYST (etripamil) for PSVT
Milestone said the FDA approved CARDAMYST (etripamil) nasal spray as a prescription medication for adults to treat PSVT episodes on demand—specifically, to convert PSVT to sinus rhythm. [2]
Milestone positioned the approval as the first FDA-approved treatment in 30+ years for a U.S. population it estimates at more than two million Americans living with PSVT—emphasizing that patients can self-administer outside emergency settings. [3]
Importantly for near-term revenue expectations, the company said CARDAMYST is expected to be available in retail pharmacies in Q1 2026. [4]
Clinical data: what the company highlighted (and why investors care)
In its approval announcement, Milestone leaned heavily on both scale and speed:
- Safety database: more than 1,800 participants and more than 2,000 PSVT episodes across the program. [5]
- Phase 3 RAPID trial (key efficacy):64% of patients who self-administered CARDAMYST converted within 30 minutes vs 31% on placebo (hazard ratio 2.62, p<0.001). [6]
- At one hour: Milestone cited 73% conversion in the treatment group. [7]
Clinical outcomes matter for adoption, but investors tend to translate them into two blunt questions:
- Will doctors prescribe it and will payers reimburse it?
- How quickly can Milestone scale commercialization without burning the balance sheet?
Those questions—more than the FDA decision itself—are what typically drive post-approval stock performance over the following weeks and months.
MIST stock this week: volatility first, certainty second
The numbers (week ending Friday, Dec. 12)
MIST entered the week trading around the mid-$2 range and ultimately finished lower, despite enthusiasm into the regulatory event.
Using daily pricing history:
- Mon, Dec. 8 close:$2.66
- Thu, Dec. 11 close:$2.95 (a sharp pre-decision move higher)
- Fri, Dec. 12 close:$2.41, down 18.31% on the day, with a massive 27.87M shares traded and an intraday range of roughly $1.61 to $3.06. [8]
That puts the stock down about 9%–10% across the week depending on whether you measure Monday-to-Friday or prior-Friday-to-Friday—while still showcasing the kind of “event risk” behavior biotech traders live for. [9]
Timing nuance that matters
Milestone’s FDA approval announcement is timestamped 8:00 p.m. ET on Dec. 12—after the regular session ended—so Friday’s regular-session plunge happened ahead of the official approval headline. [10]
That setup often produces weird tape action: some traders de-risk into binary events, others hedge with options, and the stock can swing hard even before the news becomes public.
Why would a stock drop into approval? The “sell-the-news” logic (and other plausible drivers)
A post-approval selloff (or a selloff right before an approval is confirmed) is not rare. A few forces can stack:
1) Expectations were already priced in.
If a large chunk of the investor base believed approval was likely, the stock can rise into the decision—then fall when the uncertainty is removed because there’s no longer a “lottery premium.”
2) Commercial execution replaces regulatory speculation.
FDA approval is a gate; it’s not the finish line. Next comes payer negotiations, physician education, distribution, and adherence—plus the reality that revenue often ramps slower than traders want.
3) Financing fears don’t vanish—sometimes they get louder.
Commercial launches cost money (sales force, market access, inventory, post-marketing work). Even with a cash cushion, biotech investors often assume dilution risk until product revenues become visible.
This leads directly into Milestone’s capital position and the much-watched RTW agreement.
Balance sheet and funding: cash today, royalty financing tomorrow
Milestone reported $82.6 million in cash, cash equivalents, and short-term investments as of Sept. 30, 2025. [11]
The $75 million RTW royalty purchase agreement — now front and center
In the approval release, Milestone described a $75.0 million royalty purchase agreement with RTW Investments, structured as a sale of rights to receive tiered royalties on U.S. net sales in exchange for the purchase price—subject to conditions. [12]
Milestone said an amendment extended the “approval date” requirement such that, to receive the $75 million purchase price, the company must obtain FDA marketing approval on or prior to Dec. 31, 2025 and satisfy other customary closing conditions—and it anticipates the newly announced FDA approval will satisfy the requirements to receive the purchase price. [13]
This is the kind of detail markets obsess over because it affects two things at once:
- Runway confidence (how long they can fund launch without raising more money), and
- Future economics (royalty financing can reduce long-term take-home revenue in exchange for near-term cash).
Recent financing backdrop
Earlier in 2025, Milestone also completed a public offering that produced immediate net proceeds of approximately $48.7 million (with additional gross proceeds possible if warrants are exercised), as disclosed in company materials filed with the SEC. [14]
From rejection to approval: the 2025 regulatory arc investors will keep referencing
This approval story has a plot twist that still matters for sentiment: Milestone previously received a Complete Response Letter (CRL).
In March 2025, Reuters reported the FDA declined to approve Milestone’s nasal spray and called for an inspection of a facility performing testing, sending shares sharply lower at the time. Reuters also reported the CRL referenced additional data requests related to nitrosamine impurities guidance (while noting the FDA did not raise concerns about safety or efficacy in that letter). [15]
Milestone later moved through the resubmission process, and by July 2025 it announced the FDA accepted its response for review and set a new action date (the “PDUFA date”) for December. [16]
Now that the FDA has approved the product, the narrative shifts from “can it get through the agency?” to “how clean is the launch runway?”
What analysts and market trackers are saying: targets, ratings, and the reality that they may change fast
Forecasting a small-cap biotech right after approval is like forecasting weather on a moon with active volcanoes: you can try, but you should keep your hands inside the vehicle.
Still, here’s the landscape as of today:
- MarketBeat reported Wall Street Zen downgraded Milestone from “hold” to “sell” on Dec. 13, 2025, while MarketBeat’s aggregated consensus rating remained “Hold” with an average price target of $4.50. [17]
- Investing.com displayed an average 12‑month price target of $3.75 (high $5, low $2) and noted the stock’s 52‑week range around $0.625–$3.060. [18]
Two key cautions for readers:
- Many published targets were set pre-approval and may be updated quickly after management gives launch specifics.
- Small-cap biotech targets often reflect scenario models (penetration, pricing, compliance, payer friction), so a tiny tweak in assumptions can swing “fair value” a lot.
The strategic upside: approval in PSVT opens the door for a broader franchise
Milestone explicitly framed PSVT approval as more than a single-product moment. In its Q3 update, the company said it had finalized a Phase 3 protocol (ReVeRA‑301) for atrial fibrillation with rapid ventricular rate (AFib‑RVR) and intends to leverage the regulatory pathway using PSVT data alongside a planned AFib‑RVR Phase 3 study for a potential second indication. [19]
And in the approval announcement, Milestone stated that FDA approval in PSVT enables development of AFib‑RVR under an sNDA pathway (supplemental New Drug Application). [20]
That matters because investors usually assign much higher long-term value to a product that can expand into adjacent, high-prevalence use cases—if the company can fund the studies and execute without overextending.
Week ahead (Dec. 15–19, 2025): the events and signals that could move MIST stock next
1) Monday: Milestone’s investor conference call and webcast
Milestone said management will host a conference call and live webcast at 8:00 a.m. ET on Monday, Dec. 15, 2025 to discuss the FDA approval. [21]
This is likely the single most important near-term catalyst because investors will listen for specifics that the press release doesn’t fully answer, such as:
- Launch sequencing: what “available in Q1 2026” practically means (early Q1 vs late Q1)
- Pricing and market access: payer strategy, formulary pathway, prior authorization expectations
- Commercial buildout: sales force scale, targeting strategy (EPs vs ER vs primary care), distribution and specialty pharmacy mix
- Early demand indicators: any pre-launch interest from clinicians, conference feedback, or patient advocacy engagement
- Cash burn guidance: how launch spending ramps relative to current runway
2) Potential post-approval research updates
After a first-in-decade approval in a niche cardiovascular segment, it’s common to see analysts publish rapid reaction notes. If targets or ratings shift, MIST can move sharply—especially with relatively small-cap liquidity dynamics.
3) Watch the “funding headline” channel
Because Milestone discussed anticipating receipt of the $75 million RTW purchase price following the approval (subject to conditions), traders may be sensitive to any update that confirms timing and closing mechanics. [22]
4) Technical aftershocks
Even if you don’t worship at the altar of candlesticks, it’s hard to ignore a session like Dec. 12: a huge volume spike and an extreme intraday range often leads to continued volatility as the market digests who’s trapped, who’s hedged, and who’s rotating from event-trading into longer-term positioning. [23]
Key risks (the stuff that can bite even after “winning”)
A sober checklist investors will keep circling:
- Commercial uptake risk: approval doesn’t guarantee rapid adoption; physician habit and payer friction can slow ramp.
- Launch cost vs runway: Milestone’s own financials show commercial expenses rising as it prepared for launch, and losses continuing as of Q3 2025. [24]
- Label/real-world constraints: the prescribing population is shaped by contraindications and patient selection (a normal part of medicine, but relevant for commercial forecasts). [25]
- Financing structure: royalty financing can strengthen near-term liquidity but may reduce long-term economics if sales scale. [26]
- Biotech volatility: small-cap names can swing hard on sentiment, not just fundamentals—especially around “first launch” moments.
Bottom line
Milestone Pharmaceuticals just achieved the milestone its ticker has been teasing for years: FDA approval of CARDAMYST. [27] But the market’s job is not to clap politely—it’s to price the messy next phase: execution.
Next week’s narrative will likely be written on Monday morning’s call: pricing, access, launch cadence, and cash runway. If management’s answers reduce uncertainty, MIST may find its footing. If they raise new questions—about cost, timing, or commercialization friction—the stock could keep swinging.
References
1. www.globenewswire.com, 2. www.globenewswire.com, 3. www.globenewswire.com, 4. www.globenewswire.com, 5. www.globenewswire.com, 6. www.globenewswire.com, 7. www.globenewswire.com, 8. stockanalysis.com, 9. stockanalysis.com, 10. www.globenewswire.com, 11. www.globenewswire.com, 12. www.globenewswire.com, 13. www.globenewswire.com, 14. www.sec.gov, 15. www.reuters.com, 16. www.globenewswire.com, 17. www.marketbeat.com, 18. www.investing.com, 19. www.globenewswire.com, 20. www.globenewswire.com, 21. www.globenewswire.com, 22. www.globenewswire.com, 23. stockanalysis.com, 24. www.globenewswire.com, 25. www.globenewswire.com, 26. www.globenewswire.com, 27. www.globenewswire.com
