What are the potential regulatory hurdles for the trial's amended protocol and how might they impact timelines?

Regulatory hurdles

The amended protocol now has to be re‑submitted to both the Australian Therapeutic Goods Administration (TGA) and the U.S. FDA (if data will be used for a future NDA). Key obstacles include:

• Safety‑data package – The TGA will demand a full “safety supplement” showing that the new cohort’s dose‑escalation and biomarker‑driven eligibility do not raise un‑anticipated toxicities. Any request for additional pre‑clinical or toxicology studies could add 3‑6 months to the approval cycle.
  
• Site‑approval and ethics‑committee sign‑off – Because the protocol now expands inclusion criteria and adds a combination arm, each trial site must obtain a new Clinical Trial Notification (CTN) amendment and a fresh ethics‑board endorsement. In Australia this process typically takes 4–8 weeks per site; with 5‑7 sites the cumulative lag can stretch to 2 months.
  
• Regulatory alignment for cross‑border data – If the company intends to leverage the Australian data for a U.S. submission, the FDA will require a “sponsor‑country” justification and may request a bridging study. That step can add another 2–3 months before any filing is considered “sufficiently supportive.”
  

Impact on timelines & trading implications

Taken together, the most realistic earliest “data read‑out” date shifts from the Q4 2025 window originally hinted at in the prior press release to late Q1 2026. The added regulatory lead time creates a near‑term “timeline risk” premium that is already reflected in the stock’s price action: AETH has been trading near the lower end of its 6‑month range (≈ $1.12‑$1.18) with a descending‑triangle pattern on the daily chart, suggesting the market is pricing in the probability of a delay.

From a trading perspective, the upside is limited until the TGA clears the amendment and the company confirms a concrete data‑cut‑off. A short‑position (or a hedge with a protective put) is advisable for the next 8‑10 weeks, especially if the next earnings call (today at 4:30 p.m. ET) fails to provide a firm timeline. Conversely, a breakout above the $1.20 resistance with volume could signal that the regulator’s review is proceeding smoothly, opening a buying opportunity on the expectation of a Q1 2026 read‑out and a subsequent catalyst for a potential U.S. filing.