ADC Therapeutics joins conjugate elite with Zynlonta FDA approval

The US FDA has approved Zynlonta (loncastuximab tesirine), the eleventh antibody-drug conjugate and the first for ADC Therapeutics.

Dan Stanton, Managing editor

April 27, 2021

3 Min Read
ADC Therapeutics joins conjugate elite with Zynlonta FDA approval
Image: iStock/tang90246

The US FDA has approved Zynlonta (loncastuximab tesirine), the eleventh antibody-drug conjugate and the first for ADC Therapeutics.

Zynlonta received the thumbs up from the US Food and Drug Administration (FDA) last week for the treatment of patients with relapsed or refractory (r/r) diffuse large B-cell lymphoma (DLBCL).

The antibody-drug conjugate (ADC) is composed of a humanized monoclonal antibody that binds to human CD19, conjugated through a linker to a pyrrolobenzodiazepine (PBD)-based cytotoxic warhead. PBDs are a class of compounds that kill cells by binding their DNA and interfering with replication. In nature they are made by a group of bacteria known as actinomycetes.


Image: iStock/tang90246

The approval is the latest milestone for developer ADC Therapeutics, which span out of UK-based Spirogen, an antibody-drug conjugate developer acquired by AstraZeneca in 2013.

Last May, the company raised $233 million through an initial public offering (IPO) with a substantial amount being used to support clinical development.

With the approval of Zynlonta coming a month ahead of the expected PDUFA date, ADC Therapeutics is now preparing to launch its first commercialized therapy.

In March, the firm laid out its commercial strategy for the ADC as part of an investor presentation. As part of this, management described how it is reliant on its contract development and manufacturing organizations (CDMOs) to support production. Among its partners, it names Avid Bioservices as producer of the antibody, Lonza for the payload, and BSP Pharmaceuticals for drug substance and drug product.

The company added it already has commercial supply in stock to support launch and beyond.

With only 11 products approved by the US FDA, ADC Therapeutics joins a small group of ADC developers. The other approved products are:




Trade name

Approval Year

Gemtuzumab ozogamicin


relapsed acute myelogenous leukemia (AML)


2017 (originally 2000)

Brentuximab vedotin

Seattle Genetics, Millennium/Takeda

relapsed HL and relapsed sALCL



Trastuzumab emtansine

Genentech, Roche

HER2-positive metastatic breast cancer (mBC) following treatment with trastuzumab and a maytansinoid



Inotuzumab ozogamicin


relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia



Moxetumomab pasudotox


adults with relapsed or refractory hairy cell leukemia (HCL)



Polatuzumab vedotin-piiq

Genentech, Roche

relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL)



Enfortumab vedotin

Astellas/Seattle Genetics

adult patients with locally advanced or metastatic urothelial cancer who have received a PD-1 or PD-L1 inhibitor, and a Pt-containing therapy



Trastuzumab deruxtecan

AstraZeneca/Daiichi Sankyo

adult patients with unresectable or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 based regimens



Sacituzumab govitecan


adult patients with metastatic triple-negative breast cancer (mTNBC) who have received at least two prior therapies for patients with relapsed or refractory metastatic disease



Belantamab mafodotin-blmf

GlaxoSmithKline (GSK)

adult patients with relapsed or refractory multiple myeloma



About the Author(s)

Dan Stanton

Managing editor

Journalist covering the international biopharmaceutical manufacturing and processing industries.

Founder and editor of Bioprocess Insider, a daily news offshoot of publication Bioprocess International, with expertise in the pharmaceutical and healthcare sectors, in particular, the following niches: CROs, CDMOs, M&A, IPOs, biotech, bioprocessing methods and equipment, drug delivery, regulatory affairs and business development.

From London, UK originally but currently based in Montpellier, France through a round-a-bout adventure that has seen me live and work in Leeds (UK), London, New Zealand, and China.

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