RESUMO
T cell-retargeting therapies have transformed the therapeutic landscape for hematologic diseases. T cell-dependent bispecific antibodies (TDB) function as conditional agonists that induce a polyclonal T-cell response, resulting in target cell destruction and cytokine release. The relationship between this response and its effects on surrounding innate immune populations has not been fully explored. Here we show that treatment with mosunetuzumab in patients results in natural killer (NK) cell activation in the peripheral blood. We modeled this phenomenon in vitro and found that TDB-mediated killing activated NK cells, increasing NK function and antibody-dependent cellular cytotoxicity (ADCC), and enhanced the capability of macrophages to perform antibody-dependent cellular phagocytosis (ADCP). This enhancement was triggered by cytokines released through TDB treatment, with IL2 and IFNγ being major drivers for increased ADCC and ADCP, respectively. Surprisingly, cytolytic ability could be further augmented through neutralization of IL10 for NK cells and TNFα for macrophages. Finally, we showed that TDB treatment enhanced the efficacy of Fc-driven killing to an orthogonal solid tumor target in vivo. These results provide rationale for novel antibody therapy combinations that take advantage of both adaptive and innate immune responses.
Assuntos
Anticorpos Biespecíficos , Citocinas , Humanos , Linhagem Celular Tumoral , Citotoxicidade Celular Dependente de Anticorpos , Linfócitos T , Imunidade Inata , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/uso terapêuticoRESUMO
ABSTRACT: CD20 is an established therapeutic target in B-cell malignancies. The CD20 × CD3 bispecific antibody mosunetuzumab has significant efficacy in B-cell non-Hodgkin lymphomas (NHLs). Because target antigen loss is a recognized mechanism of resistance, we evaluated CD20 expression relative to clinical response in patients with relapsed and/or refractory NHL in the phase 1/2 GO29781 trial investigating mosunetuzumab monotherapy. CD20 was studied using immunohistochemistry (IHC), RNA sequencing, and whole-exome sequencing performed centrally in biopsy specimens collected before treatment at predose, during treatment, or upon progression. Before treatment, most patients exhibited a high proportion of tumor cells expressing CD20; however, in 16 of 293 patients (5.5%) the proportion was <10%. Analyses of paired biopsy specimens from patients on treatment revealed that CD20 levels were maintained in 29 of 30 patients (97%) vs at progression, where CD20 loss was observed in 11 of 32 patients (34%). Reduced transcription or acquisition of truncating mutations explained most but not all cases of CD20 loss. In vitro modeling confirmed the effects of CD20 variants identified in clinical samples on reduction of CD20 expression and missense mutations in the extracellular domain that could block mosunetuzumab binding. This study expands the knowledge about the occurrence of target antigen loss after anti-CD20 therapeutics to include CD20-targeting bispecific antibodies and elucidates mechanisms of reduced CD20 expression at disease progression that may be generalizable to other anti-CD20 targeting agents. These results also confirm the utility of readily available IHC staining for CD20 as a tool to inform clinical decisions. This trial was registered at www.ClinicalTrials.gov as #NCT02500407.
Assuntos
Anticorpos Biespecíficos , Antineoplásicos , Linfoma de Células B , Humanos , Antígenos CD20/genética , Recidiva Local de Neoplasia/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/genética , Antineoplásicos/uso terapêuticoRESUMO
The treatment of patients with relapsed or refractory lymphoid neoplasms represents a significant clinical challenge. Here, we identify the pro-survival BCL-2 protein family member MCL-1 as a resistance factor for the BCL-2 inhibitor venetoclax in non-Hodgkin lymphoma (NHL) cell lines and primary NHL samples. Mechanistically, we show that the antibody-drug conjugate polatuzumab vedotin promotes MCL-1 degradation via the ubiquitin/proteasome system. This targeted MCL-1 antagonism, when combined with venetoclax and the anti-CD20 antibodies obinutuzumab or rituximab, results in tumor regressions in preclinical NHL models, which are sustained even off-treatment. In a Phase Ib clinical trial (NCT02611323) of heavily pre-treated patients with relapsed or refractory NHL, 25/33 (76%) patients with follicular lymphoma and 5/17 (29%) patients with diffuse large B-cell lymphoma achieved complete or partial responses with an acceptable safety profile when treated with the recommended Phase II dose of polatuzumab vedotin in combination with venetoclax and an anti-CD20 antibody.
Assuntos
Imunoconjugados , Linfoma não Hodgkin , Humanos , Proteína de Sequência 1 de Leucemia de Células Mieloides/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linfoma não Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/patologia , Rituximab/uso terapêutico , Imunoconjugados/uso terapêuticoRESUMO
T cell-engaging bispecific antibodies (TCEs) are clinically effective treatments for hematological cancers. While the utility of TCEs in solid malignancies is being explored, toxicities arising from antigen expression on normal tissues have slowed or halted several clinical trials. Here, we describe the development of TCEs that preferentially drive T cell-mediated death against target cells co-expressing two tumor-associated antigens. We show that Ly6E and B7-H4 are simultaneously expressed on approximately 50% of breast cancers, whereas normal tissue expression is limited and mostly orthogonal. Traditional bispecific TCEs targeting a singular antigen, either Ly6E or B7-H4, are active when paired with high-affinity CD3-engagers, but normal tissue expression presents a toxicity risk. Treatment with a murine cross-reactive B7-H4-TCE results in rapid and severe weight loss in mice along with damage to B7-H4-expressing tissues. To overcome on-target toxicity, we designed trispecific antibodies co-targeting Ly6E, B7-H4, and CD3 and characterized the impact of dual-antigen binding and the relative placement of each binding domain on tumor killing in vitro and in vivo. In vitro killing of tumor cells co-expressing both antigens correlates to the placement of the higher affinity B7-H4 binding domain, with only modest enhancements seen upon addition of Ly6E binding. In xenograft models, avid binding of appropriately designed trispecific TCEs enables tumor growth inhibition while evading the poor tolerability seen with active bispecific TCEs. Collectively these data highlight the potential for dual-antigen targeting to improve safety and efficacy, and expand the scope of tumors that may effectively be treated by TCEs.Abbreviations: Chimeric antigen receptor T cells (CAR-Ts), dual-antigen targeted T cell engagers (DAT-TCE), Fragment antigen-binding (Fab), Hematoxylin and eosin (H&E), Institutional Animal Care and Use Committee (IACUC), Immunoglobulin G (IgG), immunohistochemistry (IHC), NOD SCID gamma (NSG), peripheral blood mononuclear cells (PBMCs), surface plasmon resonance (SPR), T cell-engagers (TCEs).
Assuntos
Anticorpos Biespecíficos , Receptores de Antígenos Quiméricos , Animais , Anticorpos Biespecíficos/farmacologia , Linhagem Celular Tumoral , Amarelo de Eosina-(YS) , Hematoxilina , Humanos , Imunoglobulina G , Leucócitos Mononucleares , Camundongos , Camundongos SCID , Linfócitos T , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
New therapeutics and combination regimens have led to marked clinical improvements for the treatment of a subset of colorectal cancer. Immune checkpoint inhibitors have shown clinical efficacy in patients with mismatch-repair-deficient or microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC). However, patients with microsatellite-stable (MSS) or low levels of microsatellite instable (MSI-L) colorectal cancer have not benefited from these immune modulators, and the survival outcome remains poor for the majority of patients diagnosed with mCRC. In this article, we describe the discovery of a novel T-cell-dependent bispecific antibody (TDB) targeting tumor-associated antigen LY6G6D, LY6G6D-TDB, for the treatment of colorectal cancer. RNAseq analysis showed that LY6G6D was differentially expressed in colorectal cancer with high prevalence in MSS and MSI-L subsets, whereas LY6G6D expression in normal tissues was limited. IHC confirmed the elevated expression of LY6G6D in primary and metastatic colorectal tumors, whereas minimal or no expression was observed in most normal tissue samples. The optimized LY6G6D-TDB, which targets a membrane-proximal epitope of LY6G6D and binds to CD3 with high affinity, exhibits potent antitumor activity both in vitro and in vivo. In vitro functional assays show that LY6G6D-TDB-mediated T-cell activation and cytotoxicity are conditional and target dependent. In mouse xenograft tumor models, LY6G6D-TDB demonstrates antitumor efficacy as a single agent against established colorectal tumors, and enhanced efficacy can be achieved when LY6G6D-TDB is combined with PD-1 blockade. Our studies provide evidence for the therapeutic potential of LY6G6D-TDB as an effective treatment option for patients with colorectal cancer.
Assuntos
Anticorpos Biespecíficos , Neoplasias Colorretais , Imunoglobulinas , Animais , Anticorpos Biespecíficos/imunologia , Anticorpos Biespecíficos/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Imunoglobulinas/imunologia , Camundongos , Instabilidade de Microssatélites , Linfócitos T/imunologiaRESUMO
The antibody-drug conjugate (ADC) is a well-validated modality for the cell-specific delivery of small molecules with impact expanding rapidly beyond their originally-intended purpose of treating cancer. However, antibody-mediated delivery (AMD) remains inefficient, limiting its applicability to targeting highly potent payloads to cells with high antigen expression. Maximizing the number of payloads delivered per antibody is one key way in which delivery efficiency can be improved, although this has been challenging to carry out; with few exceptions, increasing the drug-to-antibody ratio (DAR) above â¼4 typically destroys the biophysical properties and in vivo efficacy for ADCs. Herein, we describe the development of a novel bioconjugation platform combining cysteine-engineered (THIOMAB) antibodies and recombinant XTEN polypeptides for the unprecedented generation of homogeneous, stable "TXCs" with DAR of up to 18. Across three different bioactive payloads, we demonstrated improved AMD to tumors and Staphylococcus aureus bacteria for high-DAR TXCs relative to conventional low-DAR ADCs.
RESUMO
PURPOSE: Targeting CD79B using antibody-drug conjugates (ADC) is an effective therapeutic strategy in B-cell non-Hodgkin lymphoma (B-NHL). We investigated DCDS0780A, an anti-CD79B ADC with THIOMAB technology (TDC) that consistently conjugates two anti-neoplastic molecules per antibody, in contrast with ADCs with heterogeneous loads. PATIENTS AND METHODS: This phase 1 study enrolled 60 patients with histologically confirmed B-NHL that had relapsed/failed to respond following ≥1 prior treatment regimens; 41 (68%) had diffuse large B-cell lymphoma (DLBCL). Fifty-one patients received DCDS0780A monotherapy once every 3 weeks (0.3-4.8 mg/kg); 9 received combination therapy (3.6-4.8 mg/kg) with rituximab. RESULTS: Fifty-four (90%) patients experienced adverse events related to study drug, the most common of which were blurred vision, fatigue, corneal deposits, neutropenia, nausea, and peripheral neuropathy. 4.8 mg/kg was the highest dose tested and the recommended phase II dose. The pharmacokinetic profile was linear at doses ≥1.2 mg/kg. Response rate in all-treated patients (N = 60) was 47% (n = 28), including 17 complete responses (28%) and 11 partial responses (18%). The median duration of response (15.2 months) was the same for all responders (n = 28) and patients with DLBCL (n = 20). CONCLUSIONS: DCDS0780A as the TDC format for CD79B was tested at higher doses than its ADC counterpart investigated earlier, leading to deep responses. However, dose intensity was limited by ocular toxicities seen at the higher doses indicating that the TDC format was unable, in the current study, to expand the therapeutic index for the CD79B target. The encouraging antitumor activity advocates continuation of investigations into novel ADC technologies.
Assuntos
Imunoconjugados , Linfoma Difuso de Grandes Células B , Neutropenia , Terapia Combinada , Humanos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Neutropenia/induzido quimicamente , Rituximab/efeitos adversosRESUMO
Despite the recent progress, multiple myeloma (MM) is still essentially incurable and there is a need for additional effective treatments with good tolerability. RO7297089 is a novel bispecific BCMA/CD16A-directed innate cell engager (ICE®) designed to induce BCMA+ MM cell lysis through high affinity binding of CD16A and retargeting of NK cell cytotoxicity and macrophage phagocytosis. Unlike conventional antibodies approved in MM, RO7297089 selectively targets CD16A with no binding of other Fcγ receptors, including CD16B on neutrophils, and irrespective of 158V/F polymorphism, and its activity is less affected by competing IgG suggesting activity in the presence of M-protein. Structural analysis revealed this is due to selective interaction with a single residue (Y140) uniquely present in CD16A opposite the Fc binding site. RO7297089 induced tumor cell killing more potently than conventional antibodies (wild-type and Fc-enhanced) and induced lysis of BCMA+ cells at very low effector-to-target ratios. Preclinical toxicology data suggested a favorable safety profile as in vitro cytokine release was minimal and no RO7297089-related mortalities or adverse events were observed in cynomolgus monkeys. These data suggest good tolerability and the potential of RO7297089 to be a novel effective treatment of MM patients.
Assuntos
Anticorpos Biespecíficos , Mieloma Múltiplo , Antígeno de Maturação de Linfócitos B , Humanos , Mieloma Múltiplo/tratamento farmacológico , Fagocitose , Receptores de IgGRESUMO
Calicheamicin antibody-drug conjugates (ADCs) are effective therapeutics for leukemias with two recently approved in the United States: Mylotarg (gemtuzumab ozogamicin) targeting CD33 for acute myeloid leukemia and Besponsa (inotuzumab ozogamicin) targeting CD22 for acute lymphocytic leukemia. Both of these calicheamicin ADCs are heterogeneous, aggregation-prone, and have a shortened half-life due to the instability of the acid-sensitive hydrazone linker in circulation. We hypothesized that we could improve upon the heterogeneity, aggregation, and circulation stability of calicheamicin ADCs by directly attaching the thiol of a reduced calicheamicin to an engineered cysteine on the antibody via a disulfide bond to generate a linkerless and traceless conjugate. We report herein that the resulting homogeneous conjugates possess minimal aggregation and display high in vivo stability with 50% of the drug remaining conjugated to the antibody after 21 days. Furthermore, these calicheamicin ADCs are highly efficacious in mouse models of both solid tumor (HER2+ breast cancer) and hematologic malignancies (CD22+ non-Hodgkin lymphoma). Safety studies in rats with this novel calicheamicin ADC revealed an increased tolerability compared with that reported for Mylotarg. Overall, we demonstrate that applying novel linker chemistry with site-specific conjugation affords an improved, next-generation calicheamicin ADC.
Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Calicheamicinas/uso terapêutico , Imunoconjugados/uso terapêutico , Animais , Antibióticos Antineoplásicos/farmacologia , Calicheamicinas/farmacologia , Modelos Animais de Doenças , Humanos , Imunoconjugados/farmacologia , CamundongosRESUMO
We are interested in developing a second generation of antibody-drug conjugates (ADCs) for the treatment of non-Hodgkin lymphoma (NHL) that could provide a longer duration of response and be more effective in indolent NHL than the microtubule-inhibiting ADCs pinatuzumab vedotin [anti-CD22-vc-monomethyl auristatin E (MMAE)] and polatuzumab vedotin (anti-CD79b-vc-MMAE). Pinatuzumab vedotin (anti-CD22-vc-MMAE) and polatuzumab vedotin (anti-CD79b-vc-MMAE) are ADCs that contain the microtubule inhibitor MMAE. Clinical trial data suggest that these ADCs have promising efficacy for the treatment of NHL; however, some patients do not respond or become resistant to the ADCs. We tested an anti-CD22 ADC with a seco-CBI-dimer payload, thio-Hu anti-CD22-(LC:K149C)-SN36248, and compared it with pinatuzumab vedotin for its efficacy and duration of response in xenograft models and its ability to deplete normal B cells in cynomolgus monkeys. We found that anti-CD22-(LC:K149C)-SN36248 was effective in xenograft models resistant to pinatuzumab vedotin, gave a longer duration of response, had a different mechanism of resistance, and was able to deplete normal B cells better than pinatuzumab vedotin. These studies provide evidence that anti-CD22-(LC:K149C)-SN36248 has the potential for longer duration of response and more efficacy in indolent NHL than MMAE ADCs and may provide the opportunity to improve outcomes for patients with NHL.
Assuntos
Aminobenzoatos/uso terapêutico , Imunoconjugados/uso terapêutico , Linfoma não Hodgkin/tratamento farmacológico , Oligopeptídeos/uso terapêutico , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Aminobenzoatos/farmacologia , Animais , Linhagem Celular Tumoral , Haplorrinos , Humanos , Imunoconjugados/farmacologia , Oligopeptídeos/farmacologiaRESUMO
Early success with brentuximab vedotin in treating classical Hodgkin lymphoma spurred an influx of at least 20 monomethyl auristatin E (MMAE) antibody-drug conjugates (ADCs) into clinical trials. While three MMAE-ADCs have been approved, most of these conjugates are no longer being investigated in clinical trials. Some auristatin conjugates show limited or no efficacy at tolerated doses, but even for drugs driving initial remissions, tumor regrowth and metastasis often rapidly occur. Here we describe the development of second-generation therapeutic ADCs targeting Lymphocyte antigen 6E (Ly6E) where the tubulin polymerization inhibitor MMAE (Compound 1) is replaced with DNA-damaging agents intended to drive increased durability of response. Comparison of a seco-cyclopropyl benzoindol-4-one (CBI)-dimer (compound 2) to MMAE showed increased potency, activity across more cell lines, and resistance to efflux by P-glycoprotein, a drug transporter commonly upregulated in tumors. Both anti-Ly6E-CBI and -MMAE conjugates drove single-dose efficacy in xenograft and patient-derived xenograft models, but seco-CBI-dimer conjugates showed reduced tumor outgrowth following multiple weeks of treatment, suggesting that they are less susceptible to developing resistance. In parallel, we explored approaches to optimize the targeting antibody. In contrast to immunization with recombinant Ly6E or Ly6E DNA, immunization with virus-like particles generated a high-affinity anti-Ly6E antibody. Conjugates to this antibody improve efficacy versus a previous clinical candidate both in vitro and in vivo with multiple cytotoxics. Conjugation of compound 2 to the second-generation antibody results in a substantially improved ADC with promising preclinical efficacy.
Assuntos
Anticorpos Monoclonais/imunologia , Antígenos de Superfície/imunologia , Antineoplásicos/imunologia , Imunoconjugados/imunologia , Oligopeptídeos/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Anticorpos Monoclonais/farmacocinética , Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Antineoplásicos Imunológicos/farmacocinética , Antineoplásicos Imunológicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/imunologia , Feminino , Proteínas Ligadas por GPI/imunologia , Células HEK293 , Humanos , Imunoconjugados/farmacocinética , Imunoconjugados/farmacologia , Camundongos SCID , Ratos Sprague-Dawley , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/imunologiaRESUMO
BACKGROUND AND PURPOSE: Polatuzumab vedotin is an antibody-drug conjugate (ADC) being developed for non-Hodgkin's lymphoma. It contains a humanized anti-CD79b IgG1 monoclonal antibody linked to monomethyl auristatin E (MMAE), an anti-mitotic agent. Polatuzumab vedotin binds to human CD79b only. Therefore, a surrogate ADC that binds to cynomolgus monkey CD79b was used to determine CD79b-mediated pharmacological effects in the monkey and to enable first-in-human clinical trials. EXPERIMENTAL APPROACH: Polatuzumab vedotin, the surrogate ADC, and the corresponding antibodies were evaluated in different assays in vitro and in animals. In vitro assessments included binding to peripheral blood mononuclear cells from different species, binding to a human and monkey CD79b-expressing cell line, binding to human Fcγ receptors, and stability in plasma across species. In vivo, ADCs were assessed for anti-tumour activity in mice, pharmacokinetics/pharmacodynamics in monkeys, and toxicity in rats and monkeys. KEY RESULTS: Polatuzumab vedotin and surrogate ADC bind with similar affinity to human and cynomolgus monkey B cells, respectively. Comparable in vitro plasma stability, in vivo anti-tumour activity, and mouse pharmacokinetics were also observed between the surrogate ADC and polatuzumab vedotin. In monkeys, only the surrogate ADC showed B-cell depletion and B-cell-mediated drug disposition, but both ADCs showed similar MMAE-driven myelotoxicity, as expected. CONCLUSIONS AND IMPLICATIONS: The suitability of the surrogate ADC for evaluation of CD79b-dependent pharmacology was demonstrated, and anti-tumour activity, pharmacokinetics/pharmacodynamics, and toxicity data with both ADCs supported the entry of polatuzumab vedotin into clinical trials.
Assuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Linfoma de Burkitt/tratamento farmacológico , Antígenos CD79/antagonistas & inibidores , Imunoconjugados/farmacologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais Humanizados , Antineoplásicos/química , Antineoplásicos/imunologia , Sítios de Ligação/efeitos dos fármacos , Linfoma de Burkitt/patologia , Antígenos CD79/imunologia , Linhagem Celular , Relação Dose-Resposta a Droga , Feminino , Humanos , Imunoconjugados/química , Imunoconjugados/imunologia , Macaca fascicularis , Masculino , Camundongos , Camundongos SCID , Conformação Molecular , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/patologia , Ratos , Ratos Sprague-Dawley , Receptores de IgG , Relação Estrutura-AtividadeRESUMO
Antibody-drug conjugates (ADCs) contain a disease-receptor antibody and a payload drug connected via a linker. The payload delivery depends on both tumor properties and ADC characteristics. In this study, we used different linkers, attachment sites, and doses to modulate payload delivery of several ADCs bearing maytansinoids (e.g., DM1), auristatins (e.g., MMAE), and DNA alkylating agents [e.g., pyrrolo[2,1-c][1,4]benzodiazepine-dimer (PBD)] as payloads in HER2- or CD22-expressing xenograft models. The tumor growth inhibition and ADC stability and exposure data were collected and analyzed from these dosed animals. The trend analysis suggests that intratumoral payload exposures that directly related the combination of conjugate linker and dose correlate with the corresponding efficacies of three payload types in two antigen-expressing xenograft models. These preliminary correlations also suggest that a minimal threshold concentration of intratumoral payload is required to support sustained efficacy. In addition, an ADC can deliver an excessive level of payload to tumors that does not enhance efficacy ("Plateau" effect). In contrast to tumor payload concentrations, the assessments of systemic exposures of total antibody (Tab) as well as the linker, dose, site of attachment, plasma stability, and drug-to-antibody ratio changes of these ADCs did not consistently rationalize the observed ADC efficacies. The requirement of a threshold payload concentration for efficacy is further supported by dose fractionation studies with DM1-, MMAE-, and PBD-containing ADCs, which demonstrated that single-dose regimens showed better efficacies than fractionated dosing. Overall, this study demonstrates that 1) the linker and dose together determine the tissue payload concentration that correlates with the antitumor efficacy of ADCs and 2) an ADC can deliver an unnecessary level of payload to tumors in xenograft models.
Assuntos
Antineoplásicos Imunológicos/farmacocinética , Imunoconjugados/farmacocinética , Receptor ErbB-2/antagonistas & inibidores , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/antagonistas & inibidores , Ado-Trastuzumab Emtansina/administração & dosagem , Ado-Trastuzumab Emtansina/farmacocinética , Animais , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/química , Benzodiazepinas/química , Brentuximab Vedotin/administração & dosagem , Brentuximab Vedotin/farmacocinética , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Feminino , Humanos , Imunoconjugados/administração & dosagem , Camundongos , Camundongos Transgênicos , Pirróis/química , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
This work discloses the first examples of antibody-drug conjugates (ADCs) that are constructed from linker-drugs bearing dimeric seco-CBI payloads (duocarmycin analogs). Several homogeneous, CD22-targeting THIOMAB antibody-drug conjugates (TDCs) containing the dimeric seco-CBI entities are shown to be highly efficacious in the WSU-DLCL2 and BJAB mouse xenograft models. Surprisingly, the seco-CBI-containing conjugates are also observed to undergo significant biotransformation in vivo in mice, rats, and monkeys and thereby form 1:1 adducts with the Alpha-1-Microglobulin (A1M) plasma protein from these species. Variation of both the payload mAb attachment site and length of the linker-drug is shown to alter the rates of adduct formation. Subsequent experiments demonstrated that adduct formation attenuates the in vitro antiproliferation activity of the affected seco-CBI-dimer TDCs, but does not significantly impact the in vivo efficacy of the conjugates. In vitro assays employing phosphatase-treated whole blood suggest that A1M adduct formation is likely to occur if the seco-CBI-dimer TDCs are administered to humans. Importantly, protein adduct formation leads to the underestimation of total antibody (Tab) concentrations using an ELISA assay but does not affect Tab values determined via an orthogonal LC-MS/MS method. Several recommendations regarding bioanalysis of future in vivo studies involving related seco-CBI-containing ADCs are provided based on these collective findings.
Assuntos
alfa-Globulinas/química , Antineoplásicos/farmacologia , Imunoconjugados/farmacologia , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dimerização , Haplorrinos , Humanos , Imunoconjugados/química , Camundongos , Ratos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
FcRH5 is a cell surface marker enriched on malignant plasma cells when compared to other hematologic malignancies and normal tissues. DFRF4539A is an anti-FcRH5 antibody-drug conjugated to monomethyl auristatin E (MMAE), a potent anti-mitotic agent. This phase I study assessed safety, tolerability, maximum tolerated dose (MTD), anti-tumor activity, and pharmacokinetics of DFRF4539A in patients with relapsed/refractory multiple myeloma. DFRF4539A was administered at 0.3-2.4 mg/kg every 3 weeks or 0.8-1.1 mg/kg weekly as a single-agent by intravenous infusion to 39 patients. Exposure of total antibody and antibody-conjugate-MMAE analytes was linear across the doses tested. There were 37 (95%) adverse events (AEs), 8 (21%) serious AEs, and 15 (39%) AEs ≥ grade 3. Anemia (n = 10, 26%) was the most common AE considered related to DFRF4539A. Two cases of grade 3 acute renal failure were attributed to DFRF4539A. There were no deaths; the MTD was not reached. DFRF4539A demonstrated limited activity in patients at the doses tested with 2 (5%) partial response, 1 (3%) minimal response, 18 (46%) stable disease, and 16 (41%) progressive disease. FcRH5 was confirmed to be expressed and occupied by antibody post-treatment and thus remains a valid myeloma target. Nevertheless, this MMAE-based antibody-drug-conjugate targeting FcRH5 was unsuccessful for myeloma.
Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Imunoconjugados/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/patologia , Receptores Fc/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Antineoplásicos Imunológicos/farmacocinética , Biomarcadores , Monitoramento de Medicamentos , Resistencia a Medicamentos Antineoplásicos , Feminino , Seguimentos , Humanos , Imunoconjugados/administração & dosagem , Imunoconjugados/efeitos adversos , Imunoconjugados/farmacocinética , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Recidiva , Retratamento , Resultado do TratamentoRESUMO
PURPOSE: The treatment of acute myeloid leukemia (AML) has not significantly changed in 40 years. Cytarabine- and anthracycline-based chemotherapy induction regimens (7 + 3) remain the standard of care, and most patients have poor long-term survival. The reapproval of Mylotarg, an anti-CD33-calicheamicin antibody-drug conjugate (ADC), has demonstrated ADCs as a clinically validated option to enhance the effectiveness of induction therapy. We are interested in developing a next-generation ADC for AML to improve upon the initial success of Mylotarg. EXPERIMENTAL DESIGN: The expression pattern of CLL-1 and its hematopoietic potential were investigated. A novel anti-CLL-1-ADC, with a highly potent pyrrolobenzodiazepine (PBD) dimer conjugated through a self-immolative disulfide linker, was developed. The efficacy and safety profiles of this ADC were evaluated in mouse xenograft models and in cynomolgus monkeys. RESULTS: We demonstrate that CLL-1 shares similar prevalence and trafficking properties that make CD33 an excellent ADC target for AML, but lacks expression on hematopoietic stem cells that hampers current CD33-targeted ADCs. Our anti-CLL-1-ADC is highly effective at depleting tumor cells in AML xenograft models and lacks target independent toxicities at doses that depleted target monocytes and neutrophils in cynomolgus monkeys. CONCLUSIONS: Collectively, our data suggest that an anti-CLL-1-ADC has the potential to become an effective and safer treatment for AML in humans, by reducing and allowing for faster recovery from initial cytopenias than the current generation of ADCs for AML.
Assuntos
Anticorpos Anti-Idiotípicos/farmacologia , Imunoconjugados/farmacologia , Lectinas Tipo C/imunologia , Leucemia Mieloide Aguda/tratamento farmacológico , Receptores Mitogênicos/imunologia , Animais , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Lectinas Tipo C/antagonistas & inibidores , Lectinas Tipo C/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/patologia , Camundongos , Receptores Mitogênicos/antagonistas & inibidores , Receptores Mitogênicos/genética , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/genética , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Few treatment options are available for acute myeloid leukemia (AML) patients. DCLL9718A is an antibody-drug conjugate that targets C-type lectin-like molecule-1 (CLL-1). This receptor is prevalent on monocytes, neutrophils, and AML blast cells, and unlike CD33, is not expressed on hematopoietic stem cells, thus providing possible hematopoietic recovery. DCLL9718A comprises an anti-CLL-1 IgG1 antibody (MCLL0517A) linked to a pyrrolobenzodiazepine (PBD) dimer payload, via a cleavable disulfide-labile linker. Here, we characterize the in vitro and in vivo stability, the pharmacokinetics (PK) and pharmacodynamics (PD) of DCLL9718A and MCLL0517A in rodents and cynomolgus monkeys. Three key PK analytes were measured in these studies: total antibody, antibody-conjugated PBD dimer and unconjugated PBD dimer. In vitro, DCLL9718A, was stable with most (> 80%) of the PBD dimer payload remaining conjugated to the antibody over 96 hours. This was recapitulated in vivo with antibody-conjugated PBD dimer clearance estimates similar to DCLL9718A total antibody clearance. Both DCLL9718A and MCLL0517A showed linear PK in the non-binding rodent species, and non-linear PK in cynomolgus monkeys, a binding species. The PK data indicated minimal impact of conjugation on the disposition of DCLL9718A total antibody. Finally, in cynomolgus monkey, MCLL0517A showed target engagement at all doses tested (0.5 and 20 mg/kg) as measured by receptor occupancy, and DCLL9718A (at doses of 0.05, 0.1 and 0.2 mg/kg) showed strong PD activity as evidenced by notable reduction in monocytes and neutrophils.
Assuntos
Imunoconjugados/farmacocinética , Imunoconjugados/uso terapêutico , Leucemia Mieloide/tratamento farmacológico , Leucemia Mieloide/metabolismo , Doença Aguda , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Área Sob a Curva , Benzodiazepinas/imunologia , Benzodiazepinas/uso terapêutico , Humanos , Imunoconjugados/imunologia , Imunoglobulina G/imunologia , Imunoglobulina G/uso terapêutico , Lectinas Tipo C/imunologia , Leucemia Mieloide/sangue , Macaca fascicularis , Taxa de Depuração Metabólica , Camundongos , Pirróis/imunologia , Pirróis/uso terapêutico , Ratos , Receptores Mitogênicos/imunologia , Especificidade da EspécieRESUMO
For antibody-drug conjugates (ADCs) that carry a cytotoxic drug, doses that can be administered in preclinical studies are typically limited by tolerability, leading to a narrow dose range that can be tested. For molecules with non-linear pharmacokinetics (PK), this limited dose range may be insufficient to fully characterize the PK of the ADC and limits translation to humans. Mathematical PK models are frequently used for molecule selection during preclinical drug development and for translational predictions to guide clinical study design. Here, we present a practical approach that uses limited PK and receptor occupancy (RO) data of the corresponding unconjugated antibody to predict ADC PK when conjugation does not alter the non-specific clearance or the antibody-target interaction. We used a 2-compartment model incorporating non-specific and specific (target mediated) clearances, where the latter is a function of RO, to describe the PK of anti-CD33 ADC with dose-limiting neutropenia in cynomolgus monkeys. We tested our model by comparing PK predictions based on the unconjugated antibody to observed ADC PK data that was not utilized for model development. Prospective prediction of human PK was performed by incorporating in vitro binding affinity differences between species for varying levels of CD33 target expression. Additionally, this approach was used to predict human PK of other previously tested anti-CD33 molecules with published clinical data. The findings showed that, for a cytotoxic ADC with non-linear PK and limited preclinical PK data, incorporating RO in the PK model and using data from the corresponding unconjugated antibody at higher doses allowed the identification of parameters to characterize monkey PK and enabled human PK predictions.
Assuntos
Algoritmos , Anticorpos Monoclonais/farmacocinética , Imunoconjugados/farmacocinética , Modelos Biológicos , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Animais , Anticorpos Monoclonais/imunologia , Linhagem Celular Tumoral , Células HEK293 , Humanos , Imunoconjugados/imunologia , Macaca fascicularis , Estudos Prospectivos , Especificidade da EspécieRESUMO
Antibody-drug conjugates (ADC) have become important scaffolds for targeted cancer therapies. However, ADC exposure-response correlation is not well characterized. We demonstrated that intratumor payload exposures correlated well with the corresponding efficacies of several disulfide-linked ADCs, bearing an DNA alkylating agent, pyrrolo[2,1-c][1,4]benzodiazepine-dimer (PBD), in HER2-expressing xenograft models. The correlation suggests that a threshold concentration of intratumor payload is required to support sustained efficacy and an ADC can deliver an excessive level of payload to tumors that does not enhance efficacy ("Plateau" effect). In contrast to tumor PBD concentrations, related assessments of systemic exposures, plasma stability, and drug-to-antibody ratio changes of related ADCs did not consistently rationalize the observed ADC efficacies. A minimal efficacious dose could be determined by ADC dose-fractionation studies in the xenograft models. Mechanistic investigations revealed that both linker immolation and linker disulfide stability are the key factors that determine intratumor PBD concentrations. Overall, this study demonstrates how a linker design can impact ADC efficacy and that the intratumor exposure of a payload drug as the molecular mechanism quantitatively correlate with and predict the antitumor efficacy of ADCs. Mol Cancer Ther; 17(3); 677-85. ©2018 AACR.