Spirogen Ltd. and Bioatla Present Positive Data on Next-Generation Warheads in ADCS Against Cancer

Published: Apr 08, 2013

London and San Diego, 8 April 2013 – Spirogen, a leading oncology-focused company developing DNA sequence targeted agents, and BioAtla LLC, a San Diego headquartered antibody therapeutics developer, today announced new data on the use of pyrrolobenzodiazepine (PBD) dimers as warheads in antibody drug conjugates (ADCs) at the annual meeting of the American Association for Cancer Research (AACR) in Washington, DC.

The study evaluated the efficacy of five ADCs against solid and hematological cancer targets. The hematological target antibody was engineered using BioAtla’s proprietary CIAO™ and BioAcceleration™ technologies and conjugated to Spirogen’s cytotoxic PBD dimers. Trastuzumab ADCs were tested against Her2-expressing human breast cancer in vivo.

For both tumour types data showed that the ADCs achieved durable complete regression and tumor free survival. The PBD dimers were not found to be cross-resistant with widely-used chemotherapeutic agents.

Professor John Hartley, lead author of the study and Director of Pre-clinical Development at Spirogen, said: “Significant activity at remarkably low doses and at low drug-antibody ratios was seen in all tumor types we studied. Antibody-PBD conjugates are the most promising next-generation oncology compounds for clinical development.”

Dr Jay M Short, Chairman and CEO of BioAtla, said: “By pairing our technologies with Spirogen’s warheads, we have achieved affinity and efficient internationalisation of these exciting novel ADCs.”

The AACR study, Abstract #2856, titled ‘Pyrrolobenzodiazepine (PBD) dimers - potent next generation warheads in antibody drug conjugates (ADCs) targeted at both solid and hematological tumors’, was authored by scientists from Spirogen, BioAtla, ADC Therapeutics, and UCL Cancer Institute, in London.

About Spirogen Limited

Spirogen Limited (“Spirogen”) was founded in 2001 as a spin-out from several institutions including University College, London. Since that time, it has developed a novel class of highly potent cytotoxic warheads based on its proprietary pyrrolobenzodiazepines (“PBD’s”), DNA minor groove binding agents, which bind and cross-link specific sites of DNA of the cancer cell. This blocks the cancer cells’ division without distorting its DNA helix, thus avoiding the common phenomenon of emergent drug resistance. In contrast, many cancer chemotherapeutics distort the structure of DNA resulting in the ability of the cancer cells to develop resistance to further therapy. Spirogen has been developing its PBD technology for more than ten years, including a standalone PBD agent already in an NCI-sponsored Phase II study in cisplatin resistant ovarian cancer. Its business model is to partner its technology with pharma and biotech for use in the development of novel drugs. It has a number of industry collaborations, including a collaboration with Genentech announced in 2011.

For further information, please visit Spirogen's website, www.spirogen.com.

About BioAtla

BioAtla, LLC, is a global biology outsourcing developer based in San Diego, CA, with research operations in San Diego and Beijing. BioAtla provides an extensive range of protein therapeutic services that include target discovery, humanization, fully human antibody generation, affinity maturation, conditional biologic generation, expression optimization, enzyme engineering, pathway engineering, epitope mapping and more. They are a pioneer in BioAcceleration™, using a global infrastructure to deliver cost-efficient access to state-of-the-art technologies and services and maximizing antibody and other protein product development opportunities for their client partners.

For more information, please visit www.bioatla.com.

About ADC Therapeutics

ADC Therapeutics sarl (ADCT) is a Swiss-based oncology drug development company that specializes in the development of proprietary Antibody Drug Conjugates (ADCs) targeting major cancers such as breast lung, prostate, renal and blood. The Company’s ADCs are highly targeted drug constructs which combine monoclonal antibodies specific to particular types of tumor cells with a novel class of highly potent pyrrolobenzodiazepine (PBD)-based warheads. As its PBD-based chemistries do not distort the structure of the DNA it gives the prospect of highly potent, target-selective cancer therapies with fewer side effects and the potential to pre-empt resistance issues faced by other anti-cancer products on the market. The company was formed in 2012. It has a strategic collaboration with Spirogen Ltd, a Celtic Therapeutics’ portfolio company, for the supply of warhead chemistries and R&D services. It operates a virtual business model based in Lausanne, Switzerland.

For further information please see: http://www.adctherapeutics.com/

About UCL Cancer Institute

The UCL Cancer Institute was established in 2007 and is the hub for cancer research at UCL. The Institute is located in the heart of London, and part of UCL [University College London]. UCL is consistently ranked within the top 20 global universities. The Cancer Institute is part of the Faculty of Medical Sciences, within the School of Life- and Medical Sciences. This School comprises the largest concentration of biomedical researchers in Europe. The Cancer Institute hosts the majority of cancer research at UCL, whilst other cancer activities across the UCL campus form part of a new Cancer Domain. The overall remit of the Institute is to develop a cancer presence and excellence, which rival other major national and international hubs for cancer research.

For media enquiries, please contact


Dr Chris Martin


m: +44 (0) 7788 720572

e: chris.martin@spirogen.com


David Wellis

t: +1 858-558-0708 x3105

e: dwellis@bioatla.com


College Hill (for media enquiries)

Sue Charles, Stefanie Bacher, Gemma Howe, Donia Al-Saffar

t: +44 (0) 20 7866 7860

e: spirogen@collegehill.com

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