## Read-through: why GOSS’s “miss” can still be a *positive signal* for the PAH kinase trade Gossamer disclosed that seralutinib in its Phase 3 PROSERA study **did not meet the primary endpoint** (change in 6-minute walk distance at Week 24), even though “separation from placebo” looked apparent in the dataset. ["Did Not Meet the Primary Endpoint"](0001728117-26-000004|1) More importantly for peers, Gossamer’s own materials emphasize that the trial likely ran into **an unusually strong placebo response** (including regional effects), which can obscure a real drug effect in functional endpoints like 6MWD. ["Elevated Placebo 6MWD Response"](0001728117-26-000004|1) ["Placebo Effect was More Pronounced"](0001728117-26-000004|1) **Hidden alpha:** A “no” on the headline endpoint paired with management’s focus on placebo dynamics and continued separation beyond Week 24 can be read as *less a mechanism failure* and more a reminder that PAH trials can be won or lost on design details, patient mix, and endpoint selection—exactly where the next entrants can differentiate. ["Continued to Separate From Placebo After Week 24"](0001728117-26-000004|1) --- ## Why this spills over to IKT specifically: IKT is explicitly positioning for a pivotal PAH shot Inhibikase has now formally aligned its disclosures around advancing **IKT-001 into a global pivotal Phase 3 trial in PAH** (the company references this plan directly in its November 2025 8-K). ["advance IKT-001 to a global pivotal Phase 3 clinical trial in PAH"](0001193125-25-291443|0) Subsequently, in its December 2025 prospectus supplement, the company reiterates that **IKT-001 is a prodrug of imatinib mesylate for PAH** and names the Phase 3 program (IMPROVE‑PAH). ["IKT-001, a prodrug of imatinib mesylate, for PAH"](0001193125-25-326883|0) ["Phase 3 study, named IMPROVE-PAH"](0001193125-25-326883|0) **The key “between-the-lines” link:** Gossamer’s readout reinforces that the market is still hunting for *disease-modifying* leverage beyond vasodilation—and Inhibikase’s own positioning is explicitly in that anti-proliferative lane (ABL and type III receptor tyrosine kinase biology, via imatinib exposure). ["aberrant signaling through the Abelson Tyrosine Kinase"](0001193125-25-326883|0) --- ## Where IKT may be structurally advantaged: endpoint strategy + adaptive design (i.e., learning from what broke PROSERA) Inhibikase discloses a **two-part adaptive Phase 3** plan where Part A targets **pulmonary vascular resistance (PVR) at Week 24** and Part B targets **6-minute walk distance at Week 24**—a structure that, at minimum, signals management is not betting the entire pivotal path on one “noisy” clinical readout. ["primary endpoint of PVR at Week 24"](0001193125-25-326883|0) ["primary endpoint will be 6-minute walk distance at Week 24"](0001193125-25-326883|0) The company also calls out operational and statistical advantages (dose titration, uninterrupted enrollment, and potential sample-size re-estimation), which is effectively a blueprint to reduce the probability of a “close but not enough” outcome. ["12-week dose-titration phase"](0001193125-25-326883|0) ["sample size re-estimation"](0001193125-25-326883|0) --- ## The near-dated catalyst the filings actually support: “Q1 2026 initiation” is on the record Inhibikase states that IMPROVE‑PAH **is expected to be initiated in the first quarter of 2026** and frames it as a global effort (up to ~180 sites worldwide). ["initiated in the first quarter of 2026"](0001193125-25-326883|0) ["up to approximately 180 sites"](0001193125-25-326883|0) **Hidden alpha:** In a tape that re-prices PAH mechanism risk immediately after a high-profile readout, the most levered setups are often the names with a *clean, date-certain next step* (trial start / protocol finalization / regulatory interaction) rather than those needing years of de-risking before the next inflection. --- ## Capitalization subtext: IKT is telling you it intends to fund the pivot The December 2025 filing is also a financing document—an “at-the-market” program **up to $185 million**—and it explicitly ties use of proceeds to clinical trials and development activities for IKT‑001. ["Up to $185,000,000"](0001193125-25-326883|0) ["clinical trials ... for IKT-001"](0001193125-25-326883|0) **Read-through:** management is signaling that once the window opens (often on sector momentum), they have a vehicle in place to raise capital into strength—dilutive, but also a practical mechanism to keep the Phase 3 timeline intact. ["broad discretion"](0001193125-25-326883|0)

## Read-through: why GOSS’s “miss” can still be a *positive signal* for the PAH kinase trade Gossamer disclosed that seralutinib in its Phase 3 PROSERA study **did not meet the primary endpoint** (change in 6-minute walk distance at Week 24), even though “separation from placebo” looked apparent in the dataset. ["Did Not Meet the Primary Endpoint"](0001728117-26-000004|1) More importantly for peers, Gossamer’s own materials emphasize that the trial likely ran into **an unusually strong placebo response** (including regional effects), which can obscure a real drug effect in functional endpoints like 6MWD. ["Elevated Placebo 6MWD Response"](0001728117-26-000004|1) ["Placebo Effect was More Pronounced"](0001728117-26-000004|1) **Hidden alpha:** A “no” on the headline endpoint paired with management’s focus on placebo dynamics and continued separation beyond Week 24 can be read as *less a mechanism failure* and more a reminder that PAH trials can be won or lost on design details, patient mix, and endpoint selection—exactly where the next entrants can differentiate. ["Continued to Separate From Placebo After Week 24"](0001728117-26-000004|1) --- ## Why this spills over to IKT specifically: IKT is explicitly positioning for a pivotal PAH shot Inhibikase has now formally aligned its disclosures around advancing **IKT-001 into a global pivotal Phase 3 trial in PAH** (the company references this plan directly in its November 2025 8-K). ["advance IKT-001 to a global pivotal Phase 3 clinical trial in PAH"](0001193125-25-291443|0) Subsequently, in its December 2025 prospectus supplement, the company reiterates that **IKT-001 is a prodrug of imatinib mesylate for PAH** and names the Phase 3 program (IMPROVE‑PAH). ["IKT-001, a prodrug of imatinib mesylate, for PAH"](0001193125-25-326883|0) ["Phase 3 study, named IMPROVE-PAH"](0001193125-25-326883|0) **The key “between-the-lines” link:** Gossamer’s readout reinforces that the market is still hunting for *disease-modifying* leverage beyond vasodilation—and Inhibikase’s own positioning is explicitly in that anti-proliferative lane (ABL and type III receptor tyrosine kinase biology, via imatinib exposure). ["aberrant signaling through the Abelson Tyrosine Kinase"](0001193125-25-326883|0) --- ## Where IKT may be structurally advantaged: endpoint strategy + adaptive design (i.e., learning from what broke PROSERA) Inhibikase discloses a **two-part adaptive Phase 3** plan where Part A targets **pulmonary vascular resistance (PVR) at Week 24** and Part B targets **6-minute walk distance at Week 24**—a structure that, at minimum, signals management is not betting the entire pivotal path on one “noisy” clinical readout. ["primary endpoint of PVR at Week 24"](0001193125-25-326883|0) ["primary endpoint will be 6-minute walk distance at Week 24"](0001193125-25-326883|0) The company also calls out operational and statistical advantages (dose titration, uninterrupted enrollment, and potential sample-size re-estimation), which is effectively a blueprint to reduce the probability of a “close but not enough” outcome. ["12-week dose-titration phase"](0001193125-25-326883|0) ["sample size re-estimation"](0001193125-25-326883|0) --- ## The near-dated catalyst the filings actually support: “Q1 2026 initiation” is on the record Inhibikase states that IMPROVE‑PAH **is expected to be initiated in the first quarter of 2026** and frames it as a global effort (up to ~180 sites worldwide). ["initiated in the first quarter of 2026"](0001193125-25-326883|0) ["up to approximately 180 sites"](0001193125-25-326883|0) **Hidden alpha:** In a tape that re-prices PAH mechanism risk immediately after a high-profile readout, the most levered setups are often the names with a *clean, date-certain next step* (trial start / protocol finalization / regulatory interaction) rather than those needing years of de-risking before the next inflection. --- ## Capitalization subtext: IKT is telling you it intends to fund the pivot The December 2025 filing is also a financing document—an “at-the-market” program **up to $185 million**—and it explicitly ties use of proceeds to clinical trials and development activities for IKT‑001. ["Up to $185,000,000"](0001193125-25-326883|0) ["clinical trials ... for IKT-001"](0001193125-25-326883|0) **Read-through:** management is signaling that once the window opens (often on sector momentum), they have a vehicle in place to raise capital into strength—dilutive, but also a practical mechanism to keep the Phase 3 timeline intact. ["broad discretion"](0001193125-25-326883|0)