Design and Synthesis of Tesirine, a Clinical Antibody–Drug Conjugate Pyrrolobenzodiazepine Dimer Payload

Tiberghien, Arnaud; Levy, Jean-Noel; Masterson, Luke A.; Patel, Neki; Adams, Lauren; Corbett, Simon; Williams, David G.; Hartley, John A.; Howard, Philip W.

doi:10.1021/acsmedchemlett.6b00062

Cited by 141 publications

(136 citation statements)

References 26 publications

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“…However, the activity of cytotoxics can be context dependent, where certain classes of drugs are more effective than others depending on the type of cancer. Therefore, studies were conducted to determine the relative activity of 5T4-Tub and 5T4-PBD, an ADC composed of 5T4_0108 conjugated with SG3249, a DNA cross-linking PBD payload (27).…”

Section: Generation and In Vitro Characterization Of 5t4_0108 Antibodymentioning

confidence: 99%

Preclinical Evaluation of MEDI0641, a Pyrrolobenzodiazepine-Conjugated Antibody–Drug Conjugate Targeting 5T4

Harper¹,

Lloyd²,

Dimasi³

et al. 2017

Molecular Cancer Therapeutics

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Antibody-drug conjugates (ADC) are used to selectively deliver cytotoxic agents to tumors and have the potential for increased clinical benefit to cancer patients. 5T4 is an oncofetal antigen overexpressed on the cell surface in many carcinomas on both bulk tumor cells as well as cancer stem cells (CSC), has very limited normal tissue expression, and can internalize when bound by an antibody. An anti-5T4 antibody was identified and optimized for efficient binding and internalization in a target-specific manner, and engineered cysteines were incorporated into the molecule for site-specific conjugation. ADCs targeting 5T4 were constructed by site-specifically conjugating the antibody with payloads that possess different mechanisms of action, either a DNA cross-linking pyrrolobenzodiazepine (PBD) dimer or a microtubule-destabilizing tubulysin, so that each ADC had a drug:antibody ratio of 2. The resulting ADCs demonstrated significant target-dependent activity in vitro and in vivo; however, the ADC conjugated with a PBD payload (5T4-PBD) elicited more durable antitumor responses in vivo than the tubulysin conjugate in xenograft models. Likewise, the 5T4-PBD more potently inhibited the growth of 5T4-positive CSCs in vivo, which likely contributed to its superior antitumor activity. Given that the 5T4-PBD possessed both potent antitumor activity as well as anti-CSC activity, and thus could potentially target bulk tumor cells and CSCs in target-positive indications, it was further evaluated in non-GLP rat toxicology studies that demonstrated excellent in vivo stability with an acceptable safety profile. Taken together, these preclinical data support further development of 5T4-PBD, also known as MEDI0641, against 5T4 þ cancer indications. Mol Cancer Ther;16(8); 1576-87. Ó2017 AACR.

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Section: Generation and In Vitro Characterization Of 5t4_0108 Antibodymentioning

confidence: 99%

Preclinical Evaluation of MEDI0641, a Pyrrolobenzodiazepine-Conjugated Antibody–Drug Conjugate Targeting 5T4

Harper¹,

Lloyd²,

Dimasi³

et al. 2017

Molecular Cancer Therapeutics

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“…Free SG3199 had an IC 50 of ~1 pM (Figure 3A, Table S1), this confirmed its toxicity towards trypanosomes and indicated that it is freely cell permeable. Prior to conjugation to the IgGs, SG3199 was modified by the addition of a linker to facilitate conjugation and release in the lysosome after proteolysis to produce SG3249(43) (Figure 1B). Free SG3249 had an IC 50 of ~240 pM (Figure 3A, Table S1); presumably the hydrophilic nature of the linker meant that cell access via passive diffusion was reduced.…”

Section: Resultsmentioning

confidence: 99%

A single dose of antibody-drug conjugate cures a stage 1 model of African trypanosomiasis

MacGregor¹,

González-Muñoz²,

Jobe³

et al. 2019

Preprint

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22Infections of humans and livestock with African trypanosomes are treated with drugs 23 introduced decades ago that are not always fully effective and often have severe 24 side effects. Here, the trypanosome haptoglobin-haemoglobin receptor (HpHbR) has 25 been exploited as a route of uptake for an antibody-drug conjugate (ADC) that is 26 completely effective against Trypanosoma brucei in the standard mouse model of 27 infection. Recombinant human anti-HpHbR monoclonal antibodies were isolated and 28 shown to be internalised in a receptor-dependent manner. Antibodies were 29 conjugated to a pyrrolobenzodiazepine (PBD) toxin and killed T. brucei in vitro at 30 picomolar concentrations. A single therapeutic dose (0.25 mg/kg) of a HpHbR 31 antibody-PBD conjugate completely cured a T. brucei mouse infection within 2 days 32 with no re-emergence of infection over a subsequent time course of 77 days. These 33 experiments provide a demonstration of how ADCs can be exploited to treat 34 protozoal diseases that desperately require new therapeutics. 35 36 Author Summary 37Here we show that antibody-drug conjugates (ADCs) can be re-purposed from 38 cancer immunotherapeutics to anti-protozoals by changing the specificity of the 39 immunoglobulin to target a trypanosome cell surface receptor. Trypanosomes were 40 used as a model system due to the availability of receptor null cell lines that allowed 41 the unambiguous demonstration that ADCs targeted to a parasite surface receptor 42 could be specifically internalised via receptor-mediated endocytosis. A single low 43 dose of the resulting ADC was able to cure a stage 1 mouse model of trypanosome 44 infection. We have used toxins and conjugation chemistry that are identical to anti-45 3 cancer ADCs demonstrating the ability to piggy-back onto the huge research efforts 46 and resources that are being invested in the development of such ADCs. 47The potential for development of ADCs against a wide range of human pathogens is 48 vast, where only epitope binding sites need vary in order to provide selectivity. This 49 provides a far-reaching opportunity for the rapid development of novel anti-50 protozoals for the targeted killing of a wide range of pathogens that cause disease 51 worldwide, especially in developing countries.

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“…PBD dimers bind in the minor groove and cross-link specific repeat sequences in the DNA through the N10 position of both monomers. 24 Two of the PBD ADCs that are currently in clinical development (SGN-CD33A and Rova-T ADCs) use PBD linker-payloads, SGD-1910 and SG3249, respectively. 25,26 Like the PBD payload, the D211 payload has IC 50 values in the picomolar range in AML cell lines.…”

Section: Discussionmentioning

confidence: 99%

CLT030, a leukemic stem cell–targeting CLL1 antibody-drug conjugate for treatment of acute myeloid leukemia

et al. 2018

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The current standard of care for acute myeloid leukemia (AML) is largely ineffective with very high relapse rates and low survival rates, mostly due to the inability to eliminate a rare population of leukemic stem cells (LSCs) that initiate tumor growth and are resistant to standard chemotherapy. RNA-sequencing analysis on isolated LSCs confirmed C-type lectin domain family 12 member A (CLL1, also known as CLEC12A) to be highly expressed on LSCs but not on normal hematopoietic stem cells (HSCs) or other healthy organ tissues. Expression of CLL1 was consistent across different types of AML. We developed CLT030 (CLL1-ADC), an antibody-drug conjugate (ADC) based on a humanized anti-CLL1 antibody with 2 engineered cysteine residues linked covalently via a cleavable linker to a highly potent DNA-binding payload, thus resulting in a site-specific and homogenous ADC product. The ADC is designed to be stable in the bloodstream and to release its DNA-binding payload only after the ADC binds to CLL1-expressing tumor cells, is internalized, and the linker is cleaved in the lysosomal compartment. CLL1-ADC inhibits in vitro LSC colony formation and demonstrates robust in vivo efficacy in AML cell tumor models and tumor growth inhibition in the AML patient-derived xenograft model. CLL1-ADC demonstrated a reduced effect on differentiation of healthy normal human CD34 cells to various lineages as observed in an in vitro colony formation assay and in an in vivo xenotransplantation model as compared with CD33-ADC. These results demonstrate that CLL1-ADC could be an effective ADC therapeutic for the treatment of AML.

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Design and Synthesis of Tesirine, a Clinical Antibody–Drug Conjugate Pyrrolobenzodiazepine Dimer Payload

Cited by 141 publications

References 26 publications

Preclinical Evaluation of MEDI0641, a Pyrrolobenzodiazepine-Conjugated Antibody–Drug Conjugate Targeting 5T4

Preclinical Evaluation of MEDI0641, a Pyrrolobenzodiazepine-Conjugated Antibody–Drug Conjugate Targeting 5T4

A single dose of antibody-drug conjugate cures a stage 1 model of African trypanosomiasis

CLT030, a leukemic stem cell–targeting CLL1 antibody-drug conjugate for treatment of acute myeloid leukemia

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