What drove the decision to add the 24-month endpoint, and does it indicate any concern about the 15-month endpoint? What is the confidence level for the 15-month endpoint?

Management is "super confident" in the Month 15 endpoint, which remains the base case. The decision to add Month 24 was opportunistic, driven by strong trial execution (over-enrollment, low discontinuation, high compliance) which provided "found money" in terms of increased statistical power. This allows for a stronger overall profile and builds a "moat" around the franchise without weakening Month 15. “So first and foremost, super confident in month 15. We are -- it is our base case... we found ourselves with increased power. And so we made the strategic decision to apply that power to a second time point. So we have not weakened the study at month 15 by any way.”

Does Annexon expect lesion growth to hit statistical significance by Month 24, and is it a secondary endpoint?

Management stated that while lesion growth is important, it's not the primary focus for vision preservation, citing that approved therapies show lesion growth protection but no vision impact. They expect to see lesion protection over time, noting a 10% protection in RPE growth in the second 6 months of ARCHER I, and encourage focus on ellipsoid zone as a primary biomarker for neurodegenerative disease. “But it's not important to protect lesion growth for the purposes of protecting vision... I would encourage you to continue to pay close attention to ellipsoid zone as a primary biomarker for this neurodegenerative disease.”

What is the commercial outlook if separation is seen at Month 15 but more static at Month 24? How would a "delayed" time to response be perceived despite vision preservation?

Management expects to be positive at Month 15, which remains the base case. They argue that achieving vision preservation at Month 15 or Month 24 would not be considered a "delay" given no other drug has achieved it, and approved drugs took 4-5 years without vision impact. The addition of Month 24 increases the probability of success for the program and provides efficacy data for the label at 2 years. “We expect to be positive at month 15. So month 15 is not kind of just kind of a speed bump, look, but we expect they get month 24. We are -- the base case is still winning at month 15.”

ANNX

Annexon (ANNX) Q2 FY26 earnings call: guidance and Q&A

Earnings call· Jun 2026 (Q2 FY26)· Health Care· Aug 12, 2026

Source: earnings call transcript

Executive summary

Annexon Q2 FY26 — ARCHER II Program Expanded, GBS BLA on Track

Annexon is advancing its lead programs, tanruprubart for GBS and vonaprument for geographic atrophy, towards regulatory milestones. The GBS program is on track for a Q4 FY26 US BLA submission, supported by compelling FORWARD study data. The GA program's ARCHER II Phase III trial was strategically expanded to include a Month 24 dual primary endpoint, aiming to strengthen the long-term profile and increase overall program success, while maintaining confidence in the Q4 FY26 Month 15 readout. The company also bolstered its financial position with a new credit facility, extending its cash runway into 2028.

Highlights

Tanruprubart (GBS) under regulatory review in Europe and on track for US BLA submission in Q4 FY26, with FORWARD study showing rapid improvement in all 10 treated patients.
Vonaprument (GA) ARCHER II Phase III trial expanded to include a Month 24 dual primary endpoint, strengthening the program and potential franchise.
Initiation of ARCHER II open-label extension (OLE) study, allowing all patients to receive vonaprument after Month 24.
Secured a credit facility with Oxford Finance for up to $200M, extending cash runway into 2028.
Strong trial execution for ARCHER II with patient discontinuation rate less than 10% and dosing compliance over 95%, exceeding targets.

Concerns

The decision to add a Month 24 primary endpoint for ARCHER II implies a split of alpha between Month 15 and Month 24, potentially tightening the statistical threshold for the Month 15 readout.
The company did not disclose the specific alpha split or the current powering for Month 15 and Month 24, leading to analyst questions about confidence in the Month 15 endpoint.

Guidance & targets

Category	Target	Timeline	Confidence
Tanruprubart (GBS) US BLA Submission	On track to submit high materiality	Q4 · FY26	High
Vonaprument (GA) ARCHER II Month 15 Primary Endpoint Readout	Expected in the fourth quarter of this year high materiality	Q4 · FY26	High
Vonaprument (GA) ARCHER II Substudy Analysis	Results expected in the first quarter of 2027 medium materiality	Q1 · FY27	Medium
Vonaprument (GA) ARCHER II Month 24 Analysis Completion	Expected to be completed in the third quarter of 2027 high materiality	Q3 · FY27	High
Cash Runway	Into 2028 high materiality	FY28	High

Deals & partnerships

Oxford Finance Credit facility providing non-dilutive capital Up to $200M

Provides access to non-dilutive capital to strengthen financial position and support growth strategies.

Risks & headwinds

ARCHER II Month 15 primary endpoint not met Q4 FY26

Potential for DMC to recommend study continue to Month 24 analysis instead of declaring positive at Month 15.

Mitigation:Strategic addition of Month 24 dual primary endpoint to increase overall program success probability; strong trial execution (low discontinuation, high compliance, over-enrollment) provides increased statistical power for both time points.

Statistical threshold for Month 15 endpoint tightened due to alpha split Ongoing

Alpha is being split between Month 15 and Month 24.

Mitigation:Management states that due to strong trial execution, the reduction in likelihood for a Month 15 win is negligible, and the study remains well-powered at both time points.

What to watch in Q3 FY26

Tanruprubart US BLA Submission

Q4 FY26

Current On track for Q4 FY26 submission

Target Submission completed

Why it matters

Successful submission is a key regulatory milestone for commercialization of the GBS program in the US.

Tanruprubart is now under regulatory review in Europe, and we are on track to submit the U.S. BLA in the fourth quarter of this year.

Find out whether ANNX delivers this. Inve re-checks your case every morning.

Q&A highlights

Has the dual primary endpoint strategy for ARCHER II been shared with regulators (US and global), and what feedback was received?

Regulators (both US and EU) have confirmed that if Annexon wants to include Month 24 efficacy data in the label, alpha would need to be applied to Month 24. This was already part of the study design for safety, but now includes efficacy.

“Yes, the short answer is, yes, both regulators on both sides of the pond have been very clear that if we want to include month 24 in the label, we would need to apply alpha to month 24.”

asked by Anupam Rama · answered by Douglas Love

2 min read 5 chapters

Detailed narrative

GBS Program Update and Regulatory Path

Annexon provided an update on its GBS program with tanruprubart, highlighting it as the first positive placebo-controlled pivotal data in 110 years. The drug is under regulatory review in Europe, and the company plans to submit the U.S. BLA in Q4 FY26.

Initial results from the FORWARD study's first cohort of 10 patients showed rapid, clinically meaningful improvement in loss of strength within 4 days, with 4 bed-bound patients regaining ability to walk. The data also showed outsized improvements in severely affected patients, including one weaned from mechanical ventilation within 4 days.

These findings are consistent with Phase III results where 90% of patients responded by week 1, supporting a broad treatment label.

GA Program Expansion and Rationale

The ARCHER II Phase III trial for vonaprument in geographic atrophy (GA) was strategically expanded to include an independent Month 24 dual primary endpoint alongside the existing Month 15 primary endpoint. This decision was driven by strong trial execution, including over-enrollment by 30 patients, a patient discontinuation rate below 10%, and dosing compliance over 95%.

Management stated the expansion strengthens the program, builds a 'moat' around the franchise, and provides additional time to demonstrate the growing treatment effect observed in proof-of-concept data, without weakening confidence in the Month 15 readout.

Vision Preservation vs. Lesion Growth in GA

Management emphasized that the primary goal for vonaprument in GA is vision preservation, not solely lesion growth reduction. They noted that while lesion growth is a current focus in the community, it has not correlated with vision preservation in previously approved therapies.

Annexon's focus is on protecting photoreceptor cells and neuronal units, as measured by ellipsoid zone, which they believe is a more critical biomarker for neurodegenerative disease. They anticipate seeing protection of RPE lesion at later time points based on Phase II data, but prioritize vision outcomes.

Financial Strengthening and Capital Structure

Annexon strengthened its financial position by securing a credit facility with Oxford Finance, providing access to up to $200 million in non-dilutive capital. This facility extends the company's cash runway into 2028, enhancing financial and operational flexibility as it prepares for global commercialization of its programs. The move also diversifies the capital structure and supports both near- and longer-term growth strategies.

Regulatory Designations and Support for Vonaprument

Vonaprument has received Fast Track designation from the FDA and PRIME designation from the EMA, making it the only geographic atrophy program with this status from the EMA. It has also been selected for the EMA's product development coordinator pilot, which offers enhanced regulatory support, including expedited scientific advice and MAA submission readiness.

These designations facilitate more frequent engagement with regulators, supporting the program's path towards potential registration.

Summary of the company's earnings call; see how call summaries are prepared. Not investment advice.