FDA clears CARVYKTI OS data on label; IEC-EC, PML warnings added

Rhea-AI Filing Summary

Legend Biotech (LEGN) announced U.S. FDA approval of a CARVYKTI label update to include overall survival (OS) results from the Phase 3 CARTITUDE-4 study. The update states CARVYKTI showed a statistically significant OS improvement versus standard of care in relapsed/refractory multiple myeloma after one to three prior lines of therapy. At a median follow-up of 33.6 months, neither treatment arm reached median OS, indicating durable survival has not yet been fully characterized.

The label also adds immune effector cell‑associated enterocolitis (IEC‑EC) to the Boxed Warnings and Warnings and Precautions, noting cases with severe or prolonged diarrhea, abdominal pain, weight loss, and rare fatalities from perforation or sepsis. Additionally, John Cunningham (JC) virus reactivation leading to progressive multifocal leukoencephalopathy (PML) was added to Warnings and Precautions (Infections) and Postmarketing Experience, including fatal cases. Physicians are advised to follow institutional guidelines for IEC‑EC management and conduct appropriate diagnostic evaluations for neurological events.

Insights

Biotech regulatory analyst

Label now includes OS benefit while adding serious safety warnings.

CARVYKTI gained an FDA label update citing a statistically significant overall survival advantage versus standard of care in CARTITUDE‑4. At a median follow‑up of 33.6 months, median OS was not reached in either arm, suggesting survival curves remain immature in absolute terms even with a favorable comparison.

Concurrently, safety content was strengthened: IEC‑EC moved into the Boxed Warnings with severe GI manifestations and rare fatal outcomes, and JC virus/PML was added to Warnings and Precautions and Postmarketing Experience. These additions formalize risk recognition and may influence patient selection and monitoring.

The net effect balances efficacy recognition with clearer risk labeling. Commercial and utilization impact will depend on clinician comfort with monitoring protocols and institutional management practices disclosed here.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16

of the Securities Exchange Act of 1934

Date of Report: October 10, 2025

Commission File Number: 001-39307

Legend Biotech Corporation

(Exact Name of Registrant as Specified in its Charter)

2101 Cottontail Lane

Somerset, New Jersey 08873

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F  ☒            Form 40-F  ☐

Legend Biotech Announces U.S. FDA Approves Label Updates for CARVYKTI^® CAR-T Cell Therapy to Include Overall Survival Data

On October 10, 2025, Legend Biotech Corporation announced that the U.S. Food and Drug Administration (FDA) has approved a label update for CARVYKTI^® (ciltacabtagene autoleucel, cilta-cel) to include the overall survival (OS) analysis from the Phase 3 CARTITUDE-4 study showing a statistically significant improvement in OS for CARVYKTI compared to the standard of care therapy in patients with relapsed, refractory multiple myeloma after one to three prior lines of therapy.

The label update is based on results from the prespecified second interim analysis of the CARTITUDE-4 study which demonstrated at a median follow-up of 33.6 months, neither CARVYKTI or standard of care therapy arms reached median OS in patients with one to three prior lines of therapy.

CARVYKTI^® Label Updated to Include Immune Effector Cell-associated Enterocolitis and John Cunningham Virus Leading to Progressive Multifocal Leukoencephalopathy

In connection with the CARVYKTI label update to include updated OS data, immune effector cell-associated enterocolitis (IEC-EC) has been added to Boxed Warnings and Warnings and Precautions section of the label. IEC-EC has occurred in patients treated with CARVYKTI with manifestations including severe or prolonged diarrhea, abdominal pain and weight loss requiring parenteral nutrition. IEC-EC has been associated with fatal outcomes from perforation or sepsis.

FDA recommends that prescribing physicians manage adverse events of IEC-EC according to institutional guidelines and conduct additional workup to exclude alternative etiologies, including T-cell lymphoma of the GI tract, which has been reported in the postmarketing setting.

Reactivation of John Cunningham (JC) virus, leading to progressive multifocal leukoencephalopathy (PML) was also added to Warnings and Precautions (under Infections) and Postmarketing Experience. PML has occurred in patients treated with CARVYKTI including cases with fatal outcomes. It is recommended that prescribing physicians perform appropriate diagnostic evaluations in patients with neurological adverse events.

This report on Form 6-K is hereby incorporated herein by reference in the registration statements of the Company on Form F-3 (Registration Nos. 333-278050, 333-272222, and 333-257625) and Form S-8 (Registration Nos. 333-239478 and 333-283217), to the extent not superseded by documents or reports subsequently filed.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	LEGEND BIOTECH CORPORATION
Date: October 10, 2025	By:	/s/ Ying Huang
	Name:	Ying Huang, Ph.D.
	Title:	Chief Executive Officer

FAQ

What did LEGN announce on its Form 6-K about CARVYKTI?

FDA approved a label update adding overall survival data from CARTITUDE-4 showing a statistically significant OS improvement versus standard of care.

What survival data were added to the CARVYKTI label?

The OS analysis from CARTITUDE-4; at 33.6 months’ median follow-up, neither CARVYKTI nor standard of care reached median OS.

Which patient population does the OS update apply to for LEGN’s CARVYKTI?

Patients with relapsed, refractory multiple myeloma after one to three prior lines of therapy.

What new safety warnings were added to CARVYKTI’s label?

Immune effector cell–associated enterocolitis (IEC-EC) added to Boxed Warnings and Warnings and Precautions; JC virus reactivation leading to PML added to Warnings and Postmarketing.

How should IEC-EC be managed according to the updated label?

FDA recommends management per institutional guidelines and additional workup to exclude alternative etiologies, including T-cell lymphoma of the GI tract.

What does the label recommend for potential PML cases?

Perform appropriate diagnostic evaluations in patients with neurological adverse events.