Milestone Pharmaceuticals (MIST) Stock Update: FDA Approves CARDAMYST (Etripamil) — This Week’s Volatility, Analyst Forecasts, and What to Watch Next (Updated Dec. 12, 2025)

Updated: Friday, December 12, 2025 (U.S. market close)

Milestone Pharmaceuticals Inc. (NASDAQ: MIST) closed out the week in the spotlight after the company announced U.S. FDA approval of CARDAMYST™ (etripamil)—positioning Milestone to transition from a development-stage biotech to a commercial-stage cardiovascular company. ^[1]

The stock action was anything but calm. MIST closed at $2.41 on Dec. 12, down 18.31%, after swinging through a wide intraday range and printing exceptionally heavy volume. After-hours trading showed a modest rebound. ^[2]

Below is a detailed breakdown of the latest Milestone Pharmaceuticals news, this week’s trading story, forecasts and analyst targets, and the week-ahead catalysts investors will be watching as CARDAMYST moves toward launch.

What’s driving MIST stock: FDA approval of CARDAMYST (etripamil) for PSVT

Late on December 12, Milestone said the FDA approved CARDAMYST (etripamil) as the first and only self-administered nasal spray for adults to convert acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm. The company framed the approval as the first FDA-approved PSVT treatment in 30+ years for more than 2 million Americans living with PSVT. ^[3]

Milestone also guided that CARDAMYST is expected to be available in retail pharmacies in Q1 2026, setting up commercialization milestones that could define the next phase for the company and its stock. ^[4]

What the clinical data says (and why it matters for commercialization)

Reports tied to the approval highlight results from Milestone’s late-stage program:

In the Phase 3 RAPID trial, 64% of patients self-administering CARDAMYST converted to normal rhythm within 30 minutes versus 31% on placebo (median time to conversion reported as 17 minutes vs. 54 minutes). ^[5]
A separate medical-news summary of trial data described conversion within 30 minutes at 59.6%, with a median conversion time of 18.5 minutes (reflecting a broader interpretation of the dataset). ^[6]
Frequently reported adverse events were primarily nasal-related (e.g., nasal discomfort, congestion, runny nose/rhinorrhea, throat irritation, nosebleed/epistaxis). ^[7]

For investors, these details matter because real-world uptake will likely hinge on how cardiologists and emergency clinicians view the product’s “at-the-ready” profile, and how payers assess its ability to reduce emergency department utilization—a theme highlighted across multiple reports. ^[8]

The “news tape” this week: the most important MIST headlines in recent days

Here are the key Milestone Pharmaceuticals developments that shaped sentiment into and through Dec. 12:

Dec. 12, 2025 — FDA approves CARDAMYST (etripamil) for PSVT; Milestone schedules an investor conference call/webcast for Monday, Dec. 15 at 8:00 a.m. ET. ^[9]
Dec. 12, 2025 — “Trading halted, news pending” headlines circulated via market-news aggregators (The Fly/TipRanks), a common pattern around major regulatory catalysts. ^[10]
Dec. 5, 2025 — Pre-decision coverage flagged the upcoming FDA action date as a defining catalyst and noted that approval would represent the first new pharmacological PSVT option in decades. ^[11]
Dec. 2, 2025 — Inducement grants: Milestone issued 30,000 stock options under its inducement plan to hire new employees (exercise price $2.69, equal to the closing price on the grant date; vesting over four years). ^[12]

MIST stock recap: what happened this week (Dec. 8–Dec. 12)

Regulatory weeks can create “binary-event” price action—fast rotations between risk-on speculation and risk-off de-risking. MIST was a textbook example.

Weekly performance snapshot (as of Dec. 12 close)

Based on daily closes from Dec. 8 through Dec. 12, MIST fell about 9.4% for the week (from $2.66 on Dec. 8 to $2.41 on Dec. 12). ^[13]

Day-by-day closes and the volatility story

Dec. 8: $2.66 (–0.75%) ^[14]
Dec. 9: $2.63 (–1.13%) ^[15]
Dec. 10: $2.67 (+1.52%) ^[16]
Dec. 11: $2.95 (+10.49%) — a classic “positioning ahead of decision” move ^[17]
Dec. 12: $2.41 (–18.31%) with an intraday high of about $3.06 and low near $1.61 ^[18]

Volume spike: investors re-priced the story in real time

Volume is often the tell during catalyst weeks. On Dec. 12, volume jumped to ~27.9 million shares, far above the prior days in the week (generally ~3–7 million shares). ^[19]

The takeaway: regardless of where MIST trades next, institutional and retail attention is elevated—and that tends to keep volatility higher than normal into the following week.

Why this approval is different from “just another biotech headline”

Investors have followed Milestone’s etripamil story through setbacks, including an FDA Complete Response Letter (CRL) earlier in 2025. In July 2025, the company said the FDA accepted its response to the CRL and set a PDUFA target action date of Dec. 13, 2025—a timeline that put December’s decision at the center of the investment thesis. ^[20]

In that July update, Milestone described the CRL as focused on chemistry/manufacturing controls (including nitrosamine-related items) and referenced an FDA inspection issue, while also stating the FDA raised no clinical or safety concerns in the CRL. ^[21]

Now, with approval in hand, the valuation debate shifts from “Will it be approved?” to questions like:

How quickly can Milestone launch and scale?
Will payers reimburse broadly and early?
How large is the addressable treated population in practice?
Does Milestone need additional capital to commercialize aggressively?

Balance sheet and funding: the runway question (and the RTW royalty financing angle)

Commercial launches are expensive—sales force buildout, market access, inventory, and patient support programs can change the burn rate quickly.

Milestone previously reported $82.6 million in cash, cash equivalents, and short-term investments as of Sept. 30, 2025, and also referenced net proceeds of about $48.7 million from an underwritten public offering completed in 2025. ^[22]

Multiple reports also highlighted a $75 million royalty financing arrangement with RTW Investments connected to FDA approval and commercialization planning. ^[23]

Investors will be watching for management’s next-level detail on:

launch spending pace,
timing of revenue inflection, and
whether the company can execute without further dilution.

Analyst forecasts and price targets: what Wall Street expects now

With the FDA decision resolved, expect models and targets to update. As of this week’s data from major tracking sites:

TipRanks shows an average 12‑month price target of $4.50 (high $5.00, low $4.00) and a “Moderate Buy” consensus based on a small analyst set. ^[24]
MarketBeat also lists a $4.50 consensus target (noting a larger analyst count on its page) and frames that as material upside from the Dec. 12 close. ^[25]

Notable rating commentary

A TipRanks-hosted summary of H.C. Wainwright commentary said analyst Brandon Folkes reiterated a Buy rating and maintained a $5.00 target, citing the anticipated launch opportunity and Milestone’s readiness following its resubmission process. ^[26]
An Investing.com report noted Jefferies raised its price target to $2 (from $1) while keeping a Hold rating, and suggested early commercialization could place significant sales beginning in Q2 2026. ^[27]

Important context: price targets are not guarantees—especially in small-cap biotech—and can change quickly after major approvals as analysts revise assumptions around pricing, uptake curves, and commercialization costs.

Week ahead: what to watch for MIST stock (Dec. 15–Dec. 19, 2025)

With approval announced, next week becomes about execution and clarity. Here are the most likely near-term catalysts:

1) The Dec. 15 conference call and webcast

Milestone scheduled a conference call/webcast for Monday, Dec. 15 at 8:00 a.m. ET to discuss the approval and next steps. This is the first major chance for management to address commercialization details and investor questions in one venue. ^[28]

What markets typically look for on calls like this:

initial launch timing and sequencing (specialty pharmacy vs retail rollout),
payer and formulary strategy,
early demand signals (KOL feedback, prescriber interest),
2026 expense guidance.

2) Launch mechanics: “available in Q1 2026” — but how early?

Milestone has said CARDAMYST should be in retail pharmacies in Q1 2026. Next week’s narrative may hinge on whether management implies early Q1 vs late Q1, and what must happen first (distribution, stocking, payer steps). ^[29]

3) Follow-on pipeline optionality (AFib-RVR)

The company has repeatedly highlighted etripamil’s potential beyond PSVT, particularly for atrial fibrillation with rapid ventricular rate (AFib‑RVR), noting an intent to pursue this via a supplemental NDA pathway after Phase 3 work. Any timeline color here can influence long-term expectations. ^[30]

4) Trading dynamics: volatility can persist even after “the” catalyst

Even with FDA approval, MIST’s trading behavior can remain headline-sensitive:

profit-taking after a run-up,
repositioning by funds that can now own a commercial-stage name,
renewed debate about whether commercialization requires more capital.

Bottom line for Milestone Pharmaceuticals stock on Dec. 12, 2025

Milestone Pharmaceuticals ends the week with the biggest possible fundamental catalyst—FDA approval of CARDAMYST—and a clear near-term roadmap toward commercialization in Q1 2026. ^[31]

At the same time, the stock’s sharp swings and volume spike show the market is actively re-pricing the company from “approval story” to “launch execution story.” ^[32]

The week ahead will likely be shaped less by the approval headline itself and more by what Milestone says (and can prove) about launch readiness, payer access, cash runway, and the pace to meaningful revenue—starting with the Dec. 15 conference call. ^[33]