Anticuerpos conjugados a fármaco: la nueva generación de terapias biotecnológicas contra el cáncer / Antibody-drug conjugates: the new generation of biotechnological therapies against cancer

Resumen Los anticuerpos terapéuticos son proteínas recombinantes empleadas en el tratamiento del cáncer. Existe una nueva generación de anticuerpos monoclonales con actividad contra las células cancerosas, conocidos como anticuerpos conjugados a fármacos. Estas moléculas están integradas por tres elementos: un anticuerpo monoclonal, un fármaco citotóxico con alta potencia y un enlazador químico que los une. El anticuerpo reconoce antígenos tumorales, por lo que permite la entrega dirigida del agente citotóxico hacia las células cancerosas. Tras el reconocimiento de su antígeno, el anticuerpo conjugado a fármaco es endocitado por las células blanco, donde se induce la degradación lisosomal de la fracción proteica y se libera el fármaco citotóxico. En el presente artículo se revisan las características generales de los anticuerpos conjugados a fármacos y se describe la evidencia clínica de la eficacia y seguridad de los primeros cuatro aprobados por las agencias reguladoras de Estados Unidos y Europa.

Abstract Therapeutic antibodies are recombinant proteins used in the treatment of cancer. There is a new generation of monoclonal antibodies with activity against cancer cells, known as antibody-drug conjugates. These molecules are made up of three elements: a monoclonal antibody, a highly potent cytotoxic drug, and a chemical linker that binds them together. The antibody recognizes tumor antigens, thereby allowing targeted delivery of the cytotoxic agent to cancer cells. After recognizing its antigen, the antibody-drug conjugate is endocytosed by the target cells, where the protein fraction is degradated into lysosomes, releasing the cytotoxic drug. This article reviews antibody-drug conjugates general characteristics and describes the clinical evidence of efficacy and safety of the first four approved by regulatory agencies in the United States and Europe.

Reações infusionais imediatas a agentes imunobiológicos endovenosos no tratamento de doenças autoimunes: experiência de 2.126 procedimentos em um centro de infusão não oncológico / Immediate infusional reactions to intravenous immunobiological agents for the treatment of autoimmune diseases: experience of 2126 procedures in a non-oncologic infusion centre

Introdução: Com o crescimento do uso de drogas imunobiológicas (IBD) ampliamos o conhecimento sobre sua eficácia e segurança. Objetivo: Analisar as reações infusionais imediatas (RII) às IBD endovenosas - infliximabe (IFX), rituximabe (RTX), abatacepte (ABT) e tocilizumabe (TCZ) - no tratamento de doenças autoimunes. Método: Avaliamos 2.126 infusões feitas no CID (Centro de Infusão) em 268 pacientes. A droga usada, a indicação clínica, o tempo de infusão e o uso de pré-medicação foram determinados pelo médico prescritor. Foram consideradas RII todas as intercorrências apresentadas durante a infusão e/ou período observacional de 30 minutos. A conduta adotada nas RII seguiu os protocolos do CID. Resultados: Em relação ao tipo de IBD, as infusões foram distribuídas em: IFX (1.584; 74,5%), TCZ (226; 10,63%), RTX (185; 8,7%) e ABT (131; 6,16%). As RII foram descritas em 87 procedimentos (4,09%): 77 no grupo IFX e 10 no grupo RTX. Não foram descritas RII nos grupos de ABT e TCZ. A maioria foi considerada leve (n = 5; 41,17%) ou moderada (n = 50; 58,81%) e não houve reações graves. Das infusões interrompidas, 79 (92,9%) foram reiniciadas e concluídas com êxito. Apenas seis (0,28%) não foram concluídas por causa das RII. Conclusão: Apesar da diferença entre o número de procedimentos por droga, trata-se de uma análise de "vida real", na qual a incidência de RII foi semelhante à descrita na literatura. A baixa incidência de RII corrobora os dados de segurança tanto de forma quantitativa como qualitativa e ressalta a importância do acompanhamento médico especializado durante a infusão. .

Introduction: With the increasing use of immunobiological drugs (IBD), the knowledge about their effectiveness and safety has increased. Objective: To analyze the immediate infusional reactions (IIR) to intravenous IBD: infliximab (IFX), rituximab (RTX), abatacept (ABT) and tocilizumab (TCZ) on the treatment of autoimmune diseases. Method: 2126 infusions performed in the Infusion Centre - CID in 268 patients were analyzed. The used drug, its clinical indication, infusion time, and use of premedication were determined by the prescribing physician. All intercurrences presented during infusion and/or during a thirty minutes observation period were considered as IIR. The approach adopted in IIR followed the protocols of the Infusion Centre - CID. Results: Regarding the type of IBD, the infused drugs given were: IFX (1584, 74.5%), TCZ (226, 10.63%), RTX (185, 8.7%) and ABT (131, 6,16%). IIR were described in 87 procedures (9.4%): 77 - IFX group and 10 - RTX group. IIR were not described in ABT and TCZ groups. Most were considered as mild (n = 5; 41.17%) or moderate (n = 50, 58.81%) reactions; there were no serious reactions. Regarding to discontinue infusions, 79 (92.9%) were resumed and completed successfully. Only six (0.28% of infusions) were not completed because of IIR. Conclusion: Despite the differences between the number of procedures per drug, ours is a "real life" analysis, where the incidence of IIR was similar to that described in the literature. The low incidence of IIR corroborates the safety data, both quantitatively and qualitatively, and underscores the importance of specialized medical support during infusion. .

Description of the Efficacy and Safety of Three New Biologics in the Treatment of Rheumatoid Arthritis

English articles on abatacept, golimumab, and tocilizumab in rheumatoid arthritis published between 2002 and 2009 were reviewed systematically. All randomized clinical trials, open-label extensions, meta-analyses, and reviews were examined. There were thirteen articles on abatacept, four on golimumab, and seven on tocilizumab. All three drugs were effective in methotrexate-naive, methotrexate-incomplete responders, and tumor-necrosis-factor-failure rheumatoid arthritis patients. Of the three, only abatacept has been tested in a head-to-head trial with infliximab, in which it was found to be equivalent to infliximab. Golimumab resulted in a more modest improvement than the others in methotrexate-naive patients, although no direct comparisons among the three drugs were possible or appropriate. Descriptive analysis of adverse events showed that patients receiving abatacept, golimumab, and tocilizumab were subject to more adverse events than controls overall, as expected. In the abatacept studies, a few cases of tuberculosis, more cardiovascular events and gastrointestinal bleedings and more basal cell carcinoma were seen. Golimumab was associated with more skin rashes and pneumonia, while tocilizumab was associated with increased lipids, more liver-function abnormalities, and neutropenia. These new medications are useful additions to the rheumatologic armamentarium and represent greater convenience (golimumab) or different mechanisms of action (abatacept and tocilizumab) than tumor-necrosis-factor inhibitors for treating rheumatoid arthritis. As expected, some adverse events occur when using these drugs and patients need to be watched carefully.

IL-2 Pathway Blocking in Combination with Anti-CD154 Synergistically Establishes Mixed Macrochimerism with Limited Dose of Bone Marrow Cells and Prolongs Skin Graft Survival in Mice

To facilitate the establishment of mixed chimerism with limited dose of bone marrow (BM) cells, and to achieve tolerance in skin graft model, combined blocking of costimulatory pathway and IL-2 pathway was used in minimally myeloablative model using busulfan. BM cells (2.5 x 10(7)) of BALB/c were injected into C57BL/6 mice at day 0 with full thickness skin graft after single dose injection of busulfan (25 mg/kg) on day-1. Recipients were grouped and injected the anti-CD154, CTLA4-Ig, anti-IL-2R at days 0, 2, 4, and 6 according to protocol. Mixed macrochimerism were induced in groups treated with anti-CD154+anti-CTLA4-Ig, anti-CD154+anti-IL-2R, and anti-CD154+anti-CTLA4 Ig+anti-IL-2R. Three groups having chimerism enjoyed prolonged graft survival more than 6 months. Superantigen deletion study revealed deletion of alloreactive T cells in combined blockade treated groups. In graft versus host disease model using CFSE staining, CD4+ T cell and CD8+ T cell proliferation were reduced in groups treated with CTLA4-Ig or anti-IL-2R or both in combination with anti-CD154. However, anti-IL-2R was not so strong as CTLA4-Ig in terms of inhibition of T cell proliferation. In conclusion, IL-2 pathway blocking combined with anti-CD154 can establish macrochimerism with limited dose of BM transplantation and induce specific tolerance to allograft.

IL-2 Pathway Blocking in Combination with Anti-CD154 Synergistically Establishes Mixed Macrochimerism with Limited Dose of Bone Marrow Cells and Prolongs Skin Graft Survival in Mice

To facilitate the establishment of mixed chimerism with limited dose of bone marrow (BM) cells, and to achieve tolerance in skin graft model, combined blocking of costimulatory pathway and IL-2 pathway was used in minimally myeloablative model using busulfan. BM cells (2.5 x 10(7)) of BALB/c were injected into C57BL/6 mice at day 0 with full thickness skin graft after single dose injection of busulfan (25 mg/kg) on day-1. Recipients were grouped and injected the anti-CD154, CTLA4-Ig, anti-IL-2R at days 0, 2, 4, and 6 according to protocol. Mixed macrochimerism were induced in groups treated with anti-CD154+anti-CTLA4-Ig, anti-CD154+anti-IL-2R, and anti-CD154+anti-CTLA4 Ig+anti-IL-2R. Three groups having chimerism enjoyed prolonged graft survival more than 6 months. Superantigen deletion study revealed deletion of alloreactive T cells in combined blockade treated groups. In graft versus host disease model using CFSE staining, CD4+ T cell and CD8+ T cell proliferation were reduced in groups treated with CTLA4-Ig or anti-IL-2R or both in combination with anti-CD154. However, anti-IL-2R was not so strong as CTLA4-Ig in terms of inhibition of T cell proliferation. In conclusion, IL-2 pathway blocking combined with anti-CD154 can establish macrochimerism with limited dose of BM transplantation and induce specific tolerance to allograft.