Samsung Bioepis has won FDA Fast Track designation for SBE303, an antibody-drug conjugate and the company's first self-developed novel drug candidate after fourteen years built almost entirely on biosimilars. The Incheon, South Korea company announced the designation on 21 October 2026 for a narrow but strategically chosen population: adults with locally advanced or metastatic urothelial cancer whose disease has already progressed on a Nectin-4-targeted therapy such as Padcev (enfortumab vedotin), the market-leading drug in the same class.
SBE303's Fast Track, in four figures
Figures from Samsung Bioepis's public disclosures and ClinicalTrials.gov.
A $24 billion field Samsung Bioepis just entered
Antibody-drug conjugates, which deliver a toxic payload directly into tumor cells by riding in on an antibody, are one of oncology's fastest-growing drug classes. The category Samsung Bioepis is now betting on already has an entrenched leader: Padcev (enfortumab vedotin), developed by Seagen (now part of Pfizer) and Astellas, was the first Nectin-4-directed ADC to reach the market, winning FDA accelerated approval in December 2019. Paired with Merck's Keytruda as frontline therapy, Padcev has displaced platinum chemotherapy as the standard of care for metastatic urothelial cancer; Astellas reported Padcev sales of 60.1 billion yen, roughly $383 million, for its fiscal third quarter alone, up 45% year on year.
Antibody-drug conjugates, sized two ways by 2030
$19.6B → $24.0B
Global antibody-drug conjugate market by 2030, as forecast by GlobalInformation Inc. (cancer-specific segment) and Grand View Research (broader ADC market).
Sources: GlobalInformation Inc., Cancer Antibody Drug Conjugates market report · Grand View Research, Antibody-Drug Conjugates market report
Regulatory News outlook
We expect the Nectin-4 segment specifically to stay a small slice of the broader ADC market through 2030, since Padcev's frontline-combination approval already captures most newly diagnosed patients; SBE303's addressable population is narrower still, limited to patients who progress after a prior Nectin-4 therapy.
How we got here: GIIR's cancer-ADC segment grows from an $8.5B 2024 base to $19.6B by 2030 at its stated 15% CAGR, a figure consistent with Grand View's larger $24.0B all-ADC 2030 estimate once biosimilar and non-oncology ADC programs are added; we treat the roughly $4.4B gap between the two as the non-cancer and non-Nectin-4 portion of the broader category, not a contradiction between the two forecasts.
SBE303 is not trying to beat Padcev head-on. Its Fast Track designation, granted 21 October 2026, specifically covers adults with locally advanced or metastatic urothelial cancer who have already received a Nectin-4-targeted therapy — patients for whom Padcev, or a drug like it, has already stopped working. That is a second-line bet inside a first-line-dominated market, and the Phase 1 trial now underway will decide whether it is a defensible one.
SBE303 against the Nectin-4 field it would follow
| Product | Company | Target population | Status |
|---|---|---|---|
| SBE303 (Samsung Bioepis) | Nectin-4 ADC, topoisomerase I payload | Urothelial cancer after a prior Nectin-4 therapy | Phase 1, FDA Fast Track (Oct 2026) |
| Padcev (Astellas / Pfizer) | Nectin-4 ADC, MMAE payload | Urothelial cancer, first-line (with Keytruda) and later lines | FDA approved since 2019; EU, Japan approved |
From each company's own labelling, announcements and ClinicalTrials.gov; not a clinical comparison. Samsung Bioepis has not disclosed a head-to-head trial against Padcev.
What closer FDA dialogue actually buys
Fast Track status does not approve or accelerate a drug by itself; it entitles a sponsor to more frequent meetings and written communication with FDA during development, and opens the door to rolling review of a future application. For a company whose entire regulatory history is built on biosimilars — drugs where the development question is whether a copy matches a reference product, not whether a new mechanism works at all — that closer dialogue matters more than it would for an experienced originator. Jung Byoung-in, Samsung Bioepis's vice president and head of regulatory affairs, said the designation “establishes an important regulatory framework for the program, enabling closer dialogue and more frequent interactions with the Agency” as the company's global Phase 1 study advances.
“[The Fast Track designation] establishes an important regulatory framework for the program, enabling closer dialogue and more frequent interactions with the Agency.” Jung Byoung-in, Vice President and Head of Regulatory Affairs, Samsung Bioepis — on the 21 October 2026 designation, reported by Targeted Oncology
Three things SBE303 is betting on
A gap Padcev leaves open
SBE303's designated population is patients who have already received a Nectin-4-targeted therapy and progressed — the population Padcev's own frontline success is creating, rather than one SBE303 has to win away from it directly.
A linker built to widen the margin
Samsung Bioepis describes SBE303's anti-Nectin-4 antibody, topoisomerase I inhibitor payload and proprietary linker as designed to widen the gap between an effective dose and a toxic one — a gap the company says is relatively narrow in existing Nectin-4 ADCs.
The first of a stated annual cadence
Samsung Bioepis has said it plans to advance one new novel clinical candidate into study every year; SBE303's Fast Track designation is the first test of whether that cadence can also clear regulatory milestones, not just enter trials.
From a Biogen joint venture to a solo pipeline
Samsung Bioepis's road to a novel ADC
- 2012
Samsung Bioepis founded
A joint venture between Samsung Biologics and Biogen Idec, built to develop biosimilar versions of approved biologic drugs.
- 2021
Incheon headquarters opens
Samsung Bioepis consolidates its operations into a new headquarters in the Songdo Bio Cluster, Incheon, built to house about 1,000 employees.
- April 2022
Biogen exits
Biogen sells its remaining stake to Samsung Biologics in a deal worth up to $2.3 billion, making Samsung Bioepis a wholly Samsung-owned company.
- December 2025
SBE303 IND cleared
FDA clears the investigational new drug application for SBE303, the company's first self-developed novel drug candidate.
- March 2026
Phase 1 trial begins
First-in-human dosing starts in a 149-patient, open-label, multi-center study (NCT07524348) in advanced refractory solid tumors.
- April 2026
Nonclinical data at AACR
Samsung Bioepis presents SBE303's pharmacology, pharmacokinetics and toxicology findings at the American Association for Cancer Research annual meeting.
- 21 October 2026
FDA Fast Track granted
FDA designates SBE303 Fast Track for urothelial cancer patients previously treated with a Nectin-4-targeted therapy.
- Through July 2030
Phase 1 runs to completion
The trial's estimated completion date, after which Samsung Bioepis would need to decide on a pivotal trial design.
Nine biosimilars and one new bet
SBE303 has produced no published human efficacy or safety data; everything on the record so far is nonclinical pharmacology and the trial's design, not its results. Fast Track designation can be withdrawn if a program's promise does not hold up, and it carries no guarantee of accelerated approval eligibility, which depends on later clinical data meeting that pathway's own standards. Samsung Bioepis has not disclosed pricing, launch timing, or a pivotal trial design for SBE303, and the company's broader pipeline strategy — nine additional biosimilars alongside a yearly cadence of novel candidates, per its own January 2026 investor update — means SBE303 competes for development resources inside Samsung Bioepis as much as it will eventually compete against Padcev in the clinic.
- Trial status: Phase 1, first-in-human, 149 patients, NCT07524348, estimated completion July 2030.
- Population: locally advanced or metastatic urothelial cancer in adults who have already received a Nectin-4-targeted therapy.
- What Fast Track changes: more frequent FDA communication and potential eligibility for rolling review; not an approval, and not a guarantee of accelerated approval.
- Company structure: wholly owned by Samsung Biologics via Samsung Epis Holdings since Biogen's April 2022 exit; no separate public listing.
Sources & further reading
- “Samsung Bioepis' first ADC candidate wins FDA Fast Track,” The Korea Herald, 21 October 2026. koreaherald.com
- “FDA Grants Fast Track Status to SBE303 in Urothelial Cancer,” Targeted Oncology, October 2026. targetedonc.com
- “Samsung Bioepis wins FDA Fast Track for 1st anticancer drug candidate,” The Korea Times, 21 October 2026. koreatimes.co.kr
- Samsung Bioepis, “Samsung Bioepis Presents Nonclinical Data for its First Novel Antibody Drug Conjugate Candidate SBE303 at AACR 2026,” press release, 20 April 2026. businesswire.com
- ClinicalTrials.gov, SBE303 Phase 1 study record, NCT07524348. clinicaltrials.gov
- “Samsung Epis targets nine additional biosimilars, drug development expansion in growth strategy,” Korea JoongAng Daily, January 2026. koreajoongangdaily.com
Regulatory News reports on public regulatory documents. It is not legal advice, and the primary sources above govern. If we have made an error, we will say so in public: see corrections.
Frequently asked questions
What did FDA grant Samsung Bioepis?
Fast Track designation, announced 21 October 2026, for SBE303, an antibody-drug conjugate targeting Nectin-4, in adults with locally advanced or metastatic urothelial cancer who have already received a Nectin-4-targeted therapy such as enfortumab vedotin (Padcev). Fast Track increases the frequency of FDA communication during development; it is not an approval and does not establish efficacy.
What stage of development is SBE303 in?
Phase 1. FDA cleared the IND in December 2025, and a first-in-human, open-label, multi-center trial (NCT07524348) began in March 2026, enrolling 149 patients with advanced refractory solid tumors; the trial's estimated completion is July 2030.
Is Samsung Bioepis a public company?
No. Samsung Bioepis is a wholly owned subsidiary of Samsung Epis Holdings, itself a Samsung Biologics subsidiary; it has no separate stock listing of its own. Biogen, Samsung Bioepis's original co-founding partner, sold its remaining stake to Samsung Biologics in a deal that closed in April 2022.
Is this Samsung Bioepis's first novel drug?
Yes, by the company's own description. Samsung Bioepis built its business on biosimilar versions of other companies' approved biologics; SBE303 is its first self-developed, proprietary novel drug candidate, and the company has said it plans to add one new novel clinical candidate to its pipeline each year.
