Beam Therapeutics Announces Compelling Updated Clinical Data from the Ongoing Phase 1/2 Trial of BEAM-302 in Alpha-1 Antitrypsin Deficiency (AATD) to Support Advancement to Pivotal Development

Rhea-AI Summary

Beam Therapeutics (Nasdaq: BEAM) reported updated Phase 1/2 data for BEAM-302 in alpha-1 antitrypsin deficiency showing a well-tolerated safety profile and robust biomarker responses supporting pivotal advancement.

Key findings: 60 mg produced mean steady-state total AAT of 16.1 µM, >94% M-AAT composition, ~84% reduction in Z-AAT, and all patients above the 11 µM protective threshold; pivotal cohort expected H2 2026.

Positive

• Total AAT 16.1 µM mean at 60 mg steady-state
• All patients remained >11 µM protective AAT threshold
• 94% M-AAT mean composition at 60 mg steady-state
• 84% reduction in mutant Z-AAT in 60 mg cohort
• 60 mg selected as optimal biological dose for pivotal study
• Safety profile well tolerated up to 75 mg with no SAEs

Negative

• One multi-dose patient had Grade 4 ALT and Grade 3 AST
• Grade 2 infusion-related reactions occurred in multi-dose cohort
• Transient Grade 1–2 ALT/AST elevations observed post-dose
• Clinical dataset limited to 29 patients overall

Key Figures

Total AAT level: 16.1 µM Protective AAT threshold: 11 µM Corrected M-AAT proportion: 94% +5 more

8 metrics

Total AAT level 16.1 µM Mean steady-state total AAT at 60 mg single dose

Protective AAT threshold 11 µM Stated protective AAT level; all 60 mg patients above

Corrected M-AAT proportion 94% Steady-state mean proportion of M-AAT in 60 mg cohort

Mutant Z-AAT reduction 84% Steady-state mean reduction in Z-AAT in 60 mg cohort

Max total AAT during infection 29.5 µM Peak AAT in 60 mg patient during respiratory infection

M-AAT composition at infection 95% M-AAT share of total AAT during infection episode

Patients treated 29 patients Total BEAM-302-treated across Parts A and B as of Feb 10, 2026

Follow-up duration up to 18 months Maximum follow-up time in ongoing Phase 1/2 trial

Market Reality Check

Price: $23.92 Vol: Volume 1,254,512 is below...

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Technical Shares are trading above the 200-day moving average of 23.8, near longer-term trend support.

Peers on Argus

BEAM is down 4.85% while key biotech peers are mixed: GLPG -4.67%, IDYA -1.86%, ...

BEAM is down 4.85% while key biotech peers are mixed: GLPG -4.67%, IDYA -1.86%, TARS -1.0%, TVTX -1.29%, and OCUL +0.62%, indicating stock-specific trading rather than a uniform sector move.

Previous Clinical trial Reports

5 past events · Latest: Dec 06 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 06	SCD trial update	Positive	+0.0%	Updated BEACON Phase 1/2 data for risto-cel in 31 SCD patients.
Jun 13	SCD data update	Positive	-2.2%	New BEACON Phase 1/2 BEAM-101 data showing strong HbF/HbS responses.
Mar 10	AATD initial data	Positive	-9.8%	First BEAM-302 clinical data showing genetic correction in AATD patients.
Jan 23	SCD encore data	Positive	-0.4%	Encore BEACON BEAM-101 data presentation at Tandem meetings.
Dec 07	SCD trial data	Positive	+3.0%	New BEACON BEAM-101 SCD data at ASH with robust HbF responses.

Pattern Detected

Clinical trial updates have often seen muted-to-negative initial reactions, with 3 of 5 such announcements followed by negative 24-hour moves despite generally positive data.

Recent Company History

Over the past year, Beam has repeatedly highlighted positive clinical trial updates across its base-editing programs. Five clinical trial announcements since Dec 2024 showed durable hemoglobin responses in sickle cell disease and initial genetic correction in AATD, yet near-term share reactions were frequently negative or muted. Today’s BEAM-302 AATD update, with dose selection and pivotal plans, extends this trajectory of advancing base-editing assets toward potential registration pathways.

Historical Comparison

-1.9% avg move · Past clinical trial updates in BEAM averaged a -1.86% 24h move. Today’s -4.85% reaction to BEAM-302 ...

clinical trial

-1.9%

Average Historical Move clinical trial

Past clinical trial updates in BEAM averaged a -1.86% 24h move. Today’s -4.85% reaction to BEAM-302 data is more negative than the typical response to similar news.

Clinical updates have progressed from early BEAM-101 and risto-cel SCD data to initial and now more mature BEAM-302 AATD results, supporting movement toward pivotal development.

Market Pulse Summary

This announcement highlights more mature BEAM-302 Phase 1/2 data in AATD, showing durable increases ...

Analysis

This announcement highlights more mature BEAM-302 Phase 1/2 data in AATD, showing durable increases in total and corrected AAT, substantial reductions in mutant Z-AAT, and a well-tolerated profile up to 75 mg. The selection of 60 mg and a planned pivotal expansion toward an accelerated approval pathway mark an inflection for the program. Investors may track enrollment progress, 12‑month biomarker outcomes, and future regulatory interactions as key next checkpoints.

Key Terms

phase 1/2, alanine transaminase (alt), biologics licensing application (bla), accelerated approval, +1 more

5 terms

phase 1/2 medical

"BEAM-302 is being evaluated in a Phase 1/2, open-label, dose exploration..."

Phase 1/2 is a combined early-stage clinical trial that first tests a new drug or treatment for safety and the right dose, then quickly expands to check if it shows any signs of working in patients. For investors, results from a Phase 1/2 study offer an early read on both risk and potential reward—like a prototype test that both confirms a product won’t harm users and suggests whether it could sell—helping guide valuation and development decisions.

alanine transaminase (alt) medical

"Grade 1 asymptomatic alanine transaminase (ALT) and aspartate..."

Alanine transaminase (ALT) is an enzyme found mainly in the liver that shows up in blood tests when liver cells are injured or stressed. For investors, rising or abnormal ALT levels can be an early warning light—like a car dashboard alert—indicating potential liver toxicity from a drug or a company’s medical problem, which can delay approvals, trigger additional testing, or harm a company’s reputation and financial outlook.

biologics licensing application (bla) regulatory

"To support a future biologics licensing application (BLA) submission..."

A biologics licensing application (BLA) is a formal regulatory request submitted to health authorities asking for permission to sell a biological medicine, such as vaccines, therapeutic proteins, or cell therapies. Investors care because approval is the gateway to commercial sales and revenue, while rejection or delays signal development, safety or manufacturing issues; think of it like applying for a driver’s license for a complex product—approval lets it legally hit the market, while problems keep it grounded.

accelerated approval regulatory

"to advance into pivotal development to support potential accelerated approval."

Accelerated approval is a process that allows new medical treatments to be approved more quickly than usual if they address serious or life-threatening conditions and show promising early results. For investors, it signals that a treatment may reach the market sooner, potentially boosting a company's prospects, but it also involves some uncertainty since full evidence of effectiveness is still being gathered.

biomarkers medical

"accelerated approval pathway for BEAM-302 based on a primary endpoint of AAT biomarkers..."

Biomarkers are measurable indicators found in the body, such as substances in blood or tissues, that reveal information about health or disease. For investors, they can signal how well a medical treatment is working or whether a disease is developing, helping to assess the potential success or risks of healthcare companies or innovations. Think of biomarkers as biological signals that provide clues about a person’s health status.

AI-generated analysis. Not financial advice.

Treatment with 60 mg of BEAM-302 Led to Mean Steady-state Total AAT Level of 16.1 µM and All Patients Consistently and Durably Above the 11 µM Protective AAT Threshold with up to 12 Months of Follow-up

Corrected M-AAT Comprised 94% of Total AAT with a Concomitant 84% Reduction in Mutant Z-AAT Following BEAM-302 60 mg Treatment

Post-treatment Inducibility of AAT Observed During Respiratory Infection with a Patient Reaching ~30 µM Total AAT, Retaining 95% M-AAT Composition

Well-tolerated Safety Profile Observed with Single Doses of BEAM-302 up to 75 mg; Safety Consistent Across Single-dose Part A and Part B Cohorts

60 mg Selected as Optimal Biological Dose, Supported by Strong Safety and Efficacy Profile Across Single-dose Cohorts; Global Pivotal Cohort Expected to Initiate in Second Half of 2026

Beam to Host Investor Webcast Today, March 25, 2026, at 8:00 a.m. ET

CAMBRIDGE, Mass., March 25, 2026 (GLOBE NEWSWIRE) -- Beam Therapeutics Inc. (Nasdaq: BEAM), a biotechnology company developing precision genetic medicines through base editing, today announced updated safety and efficacy data from the ongoing Phase 1/2 trial of BEAM-302 and the selection of 60 mg as the optimal biological dose to advance into pivotal development to support potential accelerated approval. BEAM-302 is a liver-targeting lipid-nanoparticle (LNP) formulation designed to directly correct the underlying genetic mutation that causes the severe form of alpha-1 antitrypsin deficiency (AATD) through base editing.

“AATD is a serious genetic disease that can lead to significant liver disease over an individual’s lifespan along with progressive lung disease in adults, often leaving patients with limited treatment options and challenging, lifelong disease management,” said Jeffrey Teckman, M.D., professor of pediatrics, Saint Louis University School of Medicine. “What makes BEAM-302 particularly compelling is its ability to directly correct the underlying genetic mutation in the SERPINA1 gene that drives both lung and liver manifestations of the disease. By enabling the liver to produce corrected M-AAT for the first time while reducing the toxic mutant protein, this approach has the potential to fundamentally transform how we as clinicians treat AATD and represents a meaningful advance for patients.”

BEAM-302 Phase 1/2 Clinical Trial Data Update
BEAM-302 is being evaluated in a Phase 1/2, open-label, dose exploration and dose expansion clinical trial to investigate its safety, tolerability, pharmacodynamics, pharmacokinetics and efficacy. Part A of the trial is designed to evaluate patients with AATD-associated lung disease, while Part B evaluates patients with mild to severe liver disease, with or without lung disease. As of the February 10, 2026 data cutoff date, 29 patients have been treated with BEAM-302 in Part A (15 mg, n=3; 30 mg, n=3; 60 mg, n=6; 75 mg, n=9; 2x 60 mg, n=3) and Part B (30 mg, n=3; 60 mg, n=2) and followed for up to 18 months.

Data from 26 patients treated with single-dose BEAM-302 support a well-tolerated safety profile up to 75 mg that is consistent across Part A and Part B. Adverse events (AEs) were mild to moderate, with no serious AEs reported and no dose-limiting toxicities as of the data cutoff. Transient Grade 1 and Grade 2 infusion-related reactions (IRRs) and Grade 1 asymptomatic alanine transaminase (ALT) and aspartate aminotransferase (AST) elevations were observed. In the multi-dose cohort (n=3), following the second dose of BEAM-302, patients experienced Grade 2 IRRs, one patient had Grade 4 ALT and Grade 3 AST elevations, and one patient had a Grade 2 ALT elevation. All ALT/AST elevations were asymptomatic and did not require treatment. No bilirubin increases were observed in any patient.

Treatment with BEAM-302 led to rapid and durable increases of total and functional AAT, decreases in mutant Z-AAT, and new production of corrected M-AAT. Key data from 28 efficacy evaluable patients¹ include the following:

• After treatment with a single dose of BEAM-302 in Part A, the steady-state² circulating total AAT mean (LC-MS)³ was 16.1 µM in the 60 mg cohort (follow-up ranging from 5-12 months) and 14.4 µM in the 75 mg cohort (follow-up ranging from 2-9 months). In the multi-dose cohort, patients achieved a mean of 16.5 µM total AAT at Day 84, 28 days after the second 60 mg dose. These early data suggest a single dose of 60 mg BEAM-302 has achieved near saturation editing.
• Across all cohorts, increased total AAT in circulation was functional as demonstrated by a neutrophil elastase inhibition assay.
• Mutant Z-AAT was durably and significantly reduced after treatment with BEAM-302. The steady-state mean reduction in Z-AAT was 84% in the 60 mg cohort and 79% in the 75 mg cohort. In the multi-dose cohort, the mean reduction in Z-AAT was 80% at Day 84.
• Evidence of dynamic induction of AAT expression was observed during a respiratory infection around Month 8 in a patient in the 60 mg Part A cohort. During the infection, total AAT levels increased from steady-state levels of 15.9 µM to 29.5 µM while maintaining consistent AAT composition of 95% M-AAT.
• Following treatment with BEAM-302, newly produced corrected M-AAT comprised the majority of AAT in circulation. The steady-state mean proportion of M-AAT was 94% in the 60 mg cohort and 91% in the 75 mg cohort. In the multi-dose cohort, the mean proportion of M-AAT was 93% at Day 84.
• In Part B patients with AATD-associated liver disease, single doses of 30 mg and 60 mg BEAM-302 demonstrated consistent efficacy comparable to results observed in Part A patients without liver disease.

“These updated results, now with a robust clinical dataset from 29 patients, reinforce the potential for BEAM-302 to become a first- and best-in-class one-time treatment for patients with AATD,” said John Evans, chief executive officer of Beam Therapeutics. “Following a single dose, we observed significant increases in total AAT, production of corrected M-AAT and reductions in toxic Z-AAT, demonstrating successful correction of the underlying PiZ mutation and achievement of AAT levels consistent with MZ carriers who generally do not have either lung or liver disease in the absence of additional risk factors. The strength and consistency of this dataset support our selection of 60 mg as the go-forward dose and give us confidence in our ability to rapidly execute this next phase of pivotal development in pursuit of an accelerated approval pathway. We remain deeply committed to advancing this potentially transformative, one-time treatment for the AATD community.”

BEAM-302 Pivotal Development

Based on feedback from the U.S. Food and Drug Administration (FDA), Beam intends to pursue an accelerated approval pathway for BEAM-302 based on a primary endpoint of AAT biomarkers evaluated over 12 months, with 60 mg as the selected dose. To support a future biologics licensing application (BLA) submission, the company anticipates enrolling approximately 50 additional patients with AATD-associated lung disease, with or without liver disease, in an expansion of the ongoing open-label Phase 1/2 trial. Beam expects to initiate the pivotal cohort in the second half of 2026, leveraging its existing global clinical trial network.

Investor Webcast Information
Beam will host a conference call and webcast today, March 25, 2026, at 8:00 a.m. ET to review these updates. A live webcast of the presentation will be available under "Events" in the Investors section of the company's website at www.beamtx.com, and a replay will be available shortly after the event.

About BEAM-302
BEAM-302 is a liver-targeting lipid-nanoparticle (LNP) formulation of base editing reagents designed to correct the PiZ mutation. Patients homozygous for this mutation (PiZZ) represent the majority of patients living with severe AATD disease. A one-time A-to-G correction of the PiZ mutation with Beam’s adenine base editor has the potential to simultaneously reduce the aggregation of mutant, misfolded AAT protein that causes toxicity to the liver (Z-AAT), generate therapeutic levels of corrected protein (M-AAT), and increase total and functional AAT in circulation, thereby addressing the underlying pathophysiology of both the liver and lung disease. In addition, the reduction in circulating PiZ has the potential to further minimize lung inflammation and dysfunction. Importantly, because BEAM-302 corrects the native AAT gene in its normal genetic location, AAT levels have been observed to increase physiologically in response to infection and inflammation in treated patients. This is a critical aspect of AAT’s normal function to regulate the body’s inflammatory response, which does not occur with currently approved protein replacement therapies. Correction of the PiZ mutation has been durable in patients treated in Beam's clinical trial.

About Alpha-1 Antitrypsin Deficiency (AATD)
AATD is an inherited genetic disorder that can cause early onset emphysema and liver disease. The most severe and common form of AATD arises when a patient has a point mutation in both copies of the SERPINA1 gene at amino acid 342 position (E342K, also known as the PiZ mutation or the “Z” allele). This point mutation causes alpha-1 antitrypsin, or AAT, to misfold, accumulating inside liver cells rather than being secreted, resulting in very low levels (10%-15%) of circulating AAT. In addition to resulting in lower levels, the PiZ AAT protein variant is also less enzymatically effective compared to wildtype AAT protein (also known as the “M” allele). As a consequence, the lung is left unprotected from neutrophil elastase, resulting in progressive, destructive changes in the lung, such as emphysema, which can result in the need for lung transplant. The mutant AAT protein also accumulates in the liver, causing liver inflammation and cirrhosis, which can ultimately cause liver failure or cancer requiring patients to undergo a liver transplant. It is estimated that more than 100,000 individuals in the U.S. have two copies of the Z allele, known as the PiZZ genotype, although only about 10% of all patients are thought to have been diagnosed. Although augmentation therapy has been approved in the U.S. for the treatment of AATD-associated lung disease, there are currently no curative treatments and significant unmet need exists for patients with AATD.

About Beam Therapeutics
Beam Therapeutics (Nasdaq: BEAM) is a biotechnology company committed to establishing the leading, fully integrated platform for precision genetic medicines. To achieve this vision, Beam has assembled a platform with integrated gene editing, delivery and internal manufacturing capabilities. Beam’s suite of gene editing technologies is anchored by base editing, a proprietary technology that is designed to enable precise, predictable and efficient single base changes, at targeted genomic sequences, without making double-stranded breaks in the DNA. This has the potential to enable a wide range of potential therapeutic editing strategies that Beam is using to advance a diversified portfolio of base editing programs. Beam is a values-driven organization committed to its people, cutting-edge science, and a vision of providing lifelong cures to patients suffering from serious diseases.

Cautionary Note Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Investors are cautioned not to place undue reliance on these forward-looking statements, including, but not limited to, statements related to: the therapeutic applications and potential of our technology, including with respect to AATD; our plans, and anticipated timing, to advance our AATD program; the clinical trial designs and expectations for BEAM-302; our anticipated regulatory interactions and filings; and our ability to develop lifelong, curative, precision genetic medicines for patients through base editing. Each forward-looking statement is subject to important risks and uncertainties that could cause actual results to differ materially from those expressed or implied in such statement, including, without limitation, risks and uncertainties related to: our ability to develop, obtain regulatory approval for, and commercialize our product candidates, which may take longer or cost more than planned; our ability to raise additional funding, which may not be available; our ability to obtain, maintain and enforce patent and other intellectual property protection for our product candidates; the uncertainty that our product candidates will receive regulatory approval necessary to initiate or continue human clinical trials; that preclinical testing of our product candidates and preliminary or interim data from preclinical studies and clinical trials may not be predictive of the results or success of ongoing or later clinical trials; that initiation and enrollment of, and anticipated timing to advance, our clinical trials may take longer than expected; that our product candidates, including the delivery modalities we rely on to administer them, may cause serious adverse events; that our product candidates may experience manufacturing or supply interruptions or failures; risks related to competitive products; and the other risks and uncertainties identified under the headings “Risk Factors Summary” and “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2025 and in any subsequent filings with the Securities and Exchange Commission. These forward-looking statements speak only as of the date of this press release. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. We undertake no obligation to update any forward-looking statement, whether as a result of new information, future developments or otherwise, except as may be required by applicable law.

Contacts:

Investors:
Holly Manning
Beam Therapeutics
hmanning@beamtx.com

Media:
Josie Butler
1AB
josie@1abmedia.com

_____________________________

¹ One patient dosed at 60 mg in Part B was not efficacy evaluable at the time of data cutoff.
² Steady state is defined as the period beginning on a patient's Day 28 visit and lasting until that patient's Month 12 visit (or until that patient's last visit, if earlier than twelve months).
³ Circulating AAT levels measured using liquid chromatography–mass spectrometry (LC–MS) assay. LC-MS is a preferred quantitative method by regulatory authorities to assess specificity of AAT detection.

FAQ

What were the BEAM-302 Phase 1/2 results for BEAM (Nasdaq: BEAM) on March 25, 2026?

The trial showed durable biomarker responses and tolerability, with 60 mg achieving a mean total AAT of 16.1 µM. According to the company, BEAM-302 increased functional AAT, produced corrected M-AAT, and reduced toxic Z-AAT across cohorts.

Why did Beam select 60 mg as the optimal biological dose for BEAM-302 (BEAM)?

60 mg showed the best balance of safety and efficacy, with mean steady-state total AAT of 16.1 µM and 94% M-AAT composition. According to the company, those data support near-saturation editing and go-forward pivotal dosing.

What safety signals were observed with BEAM-302 in the BEAM Phase 1/2 trial?

Overall tolerability was acceptable with no serious AEs reported in single-dose cohorts; transient IRRs and mild ALT/AST rises occurred. According to the company, one multi-dose patient experienced Grade 4 ALT and Grade 3 AST elevations that were asymptomatic.

How did BEAM-302 affect mutant Z-AAT levels in treated patients (BEAM)?

BEAM-302 produced large, durable reductions in Z-AAT, with an 84% mean reduction in the 60 mg cohort. According to the company, reductions were consistent across cohorts and accompanied by new production of corrected M-AAT.

When will Beam start the pivotal cohort for BEAM-302 and how many patients are planned?

Beam expects to initiate the pivotal cohort in the second half of 2026 and plans to enroll about 50 additional patients. According to the company, the cohort will support a potential accelerated approval pathway using 12-month biomarker endpoints.

Did BEAM-302 reach protective AAT levels and maintain M-AAT composition during infection?

Yes; patients exceeded the 11 µM protective threshold and one 60 mg patient rose to ~30 µM during infection while retaining 95% M-AAT. According to the company, this shows inducible, functional AAT expression during physiologic stress.