← Sionna Therapeutics, Inc. Common Stock overview

Sionna Therapeutics, Inc. Common Stock vs ACADIA Pharmaceuticals: why the prices moved differently

Weekly · monthly · quarterly news summaries, side by side in time

Sionna Therapeutics, Inc. Common Stock (SION)

Q3 2026
▼3▲1

Sionna's lead CF drug failed; now it's cutting costs and betting on a backup

  • Lead cystic fibrosis drug failed its key trial SION-719, Sionna's main drug, did not meaningfully improve CFTR function in a Phase 2a trial — the sweat chloride change was tiny and not statistically significant. The company dropped it as a Trikafta add-on. Since the stock's value rested on this drug, shares collapsed over 90%.

    This is the single biggest force behind SION's move and the root cause of everything that followed.

  • Rival Vertex strengthened as Sionna's threat faded With Sionna's add-on approach shelved, Vertex's dominant cystic fibrosis franchise faces less competition, and Vertex shares hit new highs. That matters for Sionna because the market now sees a harder path to winning any share of the CF market.

    It explains the competitive backdrop that makes Sionna's setback worse for its long-term value.

  • 46% workforce cut to save cash after the failure Sionna is cutting nearly half its staff, costing about $6.4 million, to lower spending and stretch its cash into the second half of 2029. It's a sign of retrenchment, but it also buys time to develop the backup program.

    It shows the concrete financial and operational fallout of the trial failure, which drives the stock lower.

  • Backup combo shows promise ahead of 2027 trial Sionna is now focused on SION-451 plus SION-2222, which it will test in the AscenSION Phase 2a trial starting early 2027. New preclinical data showed these NBD1 stabilizers improved CFTR function up to normal levels, offering a possible path forward.

    It is the main counterweight — the remaining reason investors see any value in Sionna after the failure.

September 2026
▼3▲1

Sionna's lead CF drug failed; now it's cutting costs and betting on a backup

  • Lead cystic fibrosis drug failed its key trial SION-719, Sionna's main drug, did not meaningfully improve CFTR function in a Phase 2a trial — the sweat chloride change was tiny and not statistically significant. The company dropped it as a Trikafta add-on. Since the stock's value rested on this drug, shares collapsed over 90%.

    This is the single biggest force behind SION's move and the root cause of everything that followed.

  • Rival Vertex strengthened as Sionna's threat faded With Sionna's add-on approach shelved, Vertex's dominant cystic fibrosis franchise faces less competition, and Vertex shares hit new highs. That matters for Sionna because the market now sees a harder path to winning any share of the CF market.

    It explains the competitive backdrop that makes Sionna's setback worse for its long-term value.

  • 46% workforce cut to save cash after the failure Sionna is cutting nearly half its staff, costing about $6.4 million, to lower spending and stretch its cash into the second half of 2029. It's a sign of retrenchment, but it also buys time to develop the backup program.

    It shows the concrete financial and operational fallout of the trial failure, which drives the stock lower.

  • Backup combo shows promise ahead of 2027 trial Sionna is now focused on SION-451 plus SION-2222, which it will test in the AscenSION Phase 2a trial starting early 2027. New preclinical data showed these NBD1 stabilizers improved CFTR function up to normal levels, offering a possible path forward.

    It is the main counterweight — the remaining reason investors see any value in Sionna after the failure.

Latest
▼3▲1

Sionna's lead CF drug failed; now it's cutting costs and betting on a backup

  • Lead cystic fibrosis drug failed its key trial SION-719, Sionna's main drug, did not meaningfully improve CFTR function in a Phase 2a trial — the sweat chloride change was tiny and not statistically significant. The company dropped it as a Trikafta add-on. Since the stock's value rested on this drug, shares collapsed over 90%.

    This is the single biggest force behind SION's move and the root cause of everything that followed.

  • Rival Vertex strengthened as Sionna's threat faded With Sionna's add-on approach shelved, Vertex's dominant cystic fibrosis franchise faces less competition, and Vertex shares hit new highs. That matters for Sionna because the market now sees a harder path to winning any share of the CF market.

    It explains the competitive backdrop that makes Sionna's setback worse for its long-term value.

  • 46% workforce cut to save cash after the failure Sionna is cutting nearly half its staff, costing about $6.4 million, to lower spending and stretch its cash into the second half of 2029. It's a sign of retrenchment, but it also buys time to develop the backup program.

    It shows the concrete financial and operational fallout of the trial failure, which drives the stock lower.

  • Backup combo shows promise ahead of 2027 trial Sionna is now focused on SION-451 plus SION-2222, which it will test in the AscenSION Phase 2a trial starting early 2027. New preclinical data showed these NBD1 stabilizers improved CFTR function up to normal levels, offering a possible path forward.

    It is the main counterweight — the remaining reason investors see any value in Sionna after the failure.

ACADIA Pharmaceuticals Inc (ACAD)

Q3 2026
▲3▼1

Remlifanserin Phase 2 miss cuts Alzheimer's hopes; Daybue still carries ACAD

  • Remlifanserin Phase 2 failure and downgrades ACADIA's remlifanserin failed its Phase 2 primary endpoint in Alzheimer's disease psychosis, and the 30 mg dose is being dropped for lack of efficacy. Goldman reiterated Sell with a $17 target; Citi and BMO cut targets. The stock fell about 13%, as the pipeline's biggest hoped-for catalyst lost credibility.

    This is the period's dominant new event and the main reason ACAD moved.

  • Daybue guidance raised and EU approval won Acadia raised 2026 Daybue sales guidance to $480-$510 million on strong uptake of the STIX formulation, and the European Commission approved Daybue for Rett syndrome — the first such EU approval. This widens the commercial base and partly offsets the pipeline setback.

    It is the main new positive force supporting ACAD's price this period.

  • Analyst fair value and targets lifted on Daybue After the Daybue revenue beat and higher guidance, fair value was raised to $33.25 and several analysts moved targets into the mid-$30s. Citi put the stock on a 90-day upside catalyst watch tied to the remlifanserin readout — a catalyst that has now failed.

    Shows the analyst view that drove ACAD before the trial miss, and the setup that reversed.

  • Fast Track and a large dementia-psychosis market The FDA gave remlifanserin Fast Track status, and a market report projected dementia-related psychosis growing 26.2% a year through 2036, naming ACP-204 as a key therapy. These support the long-term opportunity, though the Phase 2 miss now casts doubt on it.

    Explains the regulatory and demand backdrop behind the remlifanserin story.

August 2026
▲3▼1

Remlifanserin Phase 2 miss cuts Alzheimer's hopes; Daybue still carries ACAD

  • Remlifanserin Phase 2 failure and downgrades ACADIA's remlifanserin failed its Phase 2 primary endpoint in Alzheimer's disease psychosis, and the 30 mg dose is being dropped for lack of efficacy. Goldman reiterated Sell with a $17 target; Citi and BMO cut targets. The stock fell about 13%, as the pipeline's biggest hoped-for catalyst lost credibility.

    This is the period's dominant new event and the main reason ACAD moved.

  • Daybue guidance raised and EU approval won Acadia raised 2026 Daybue sales guidance to $480-$510 million on strong uptake of the STIX formulation, and the European Commission approved Daybue for Rett syndrome — the first such EU approval. This widens the commercial base and partly offsets the pipeline setback.

    It is the main new positive force supporting ACAD's price this period.

  • Analyst fair value and targets lifted on Daybue After the Daybue revenue beat and higher guidance, fair value was raised to $33.25 and several analysts moved targets into the mid-$30s. Citi put the stock on a 90-day upside catalyst watch tied to the remlifanserin readout — a catalyst that has now failed.

    Shows the analyst view that drove ACAD before the trial miss, and the setup that reversed.

  • Fast Track and a large dementia-psychosis market The FDA gave remlifanserin Fast Track status, and a market report projected dementia-related psychosis growing 26.2% a year through 2036, naming ACP-204 as a key therapy. These support the long-term opportunity, though the Phase 2 miss now casts doubt on it.

    Explains the regulatory and demand backdrop behind the remlifanserin story.

Latest
▲3▼1

Remlifanserin Phase 2 miss cuts Alzheimer's hopes; Daybue still carries ACAD

  • Remlifanserin Phase 2 failure and downgrades ACADIA's remlifanserin failed its Phase 2 primary endpoint in Alzheimer's disease psychosis, and the 30 mg dose is being dropped for lack of efficacy. Goldman reiterated Sell with a $17 target; Citi and BMO cut targets. The stock fell about 13%, as the pipeline's biggest hoped-for catalyst lost credibility.

    This is the period's dominant new event and the main reason ACAD moved.

  • Daybue guidance raised and EU approval won Acadia raised 2026 Daybue sales guidance to $480-$510 million on strong uptake of the STIX formulation, and the European Commission approved Daybue for Rett syndrome — the first such EU approval. This widens the commercial base and partly offsets the pipeline setback.

    It is the main new positive force supporting ACAD's price this period.

  • Analyst fair value and targets lifted on Daybue After the Daybue revenue beat and higher guidance, fair value was raised to $33.25 and several analysts moved targets into the mid-$30s. Citi put the stock on a 90-day upside catalyst watch tied to the remlifanserin readout — a catalyst that has now failed.

    Shows the analyst view that drove ACAD before the trial miss, and the setup that reversed.

  • Fast Track and a large dementia-psychosis market The FDA gave remlifanserin Fast Track status, and a market report projected dementia-related psychosis growing 26.2% a year through 2036, naming ACP-204 as a key therapy. These support the long-term opportunity, though the Phase 2 miss now casts doubt on it.

    Explains the regulatory and demand backdrop behind the remlifanserin story.