monomethyl-auristatin-e and Lymphoma--Large-Cell--Anaplastic

Brentuximab vedotin (BV) is an antibody-drug conjugate that specifically delivers the potent cytotoxic drug monomethyl auristatin E (MMAE) to CD30-positive cells. BV is FDA approved for treatment of relapsed/refractory Hodgkin lymphoma and anaplastic large cell lymphoma (ALCL); however, many patients do not achieve complete remission and develop BV-resistant disease. We selected for BV-resistant Hodgkin lymphoma (L428) and ALCL (Karpas-299) cell lines using either constant (ALCL) or pulsatile (Hodgkin lymphoma) exposure to BV. We confirmed drug resistance by MTS assay and analyzed CD30 expression in resistant cells by flow cytometry, qRT-PCR, and Western blotting. We also measured drug exporter expression, MMAE resistance, and intracellular MMAE concentrations in BV-resistant cells. In addition, tissue biopsy samples from 10 Hodgkin lymphoma and 5 ALCL patients who had relapsed or progressed after BV treatment were analyzed by immunohistocytochemistry for CD30 expression. The resistant ALCL cell line, but not the Hodgkin lymphoma cell line, demonstrated downregulated CD30 expression compared with the parental cell line. In contrast, the Hodgkin lymphoma cell line, but not the ALCL cell line, exhibited MMAE resistance and increased expression of the MDR1 drug exporter compared with the parental line. For both Hodgkin lymphoma and ALCL, samples from patients relapsed/resistant on BV persistently expressed CD30 by immunohistocytochemistry. One Hodgkin lymphoma patient sample expressed MDR1 by immunohistocytochemistry. Although loss of CD30 expression is a possible mode of BV resistance in ALCL in vitro models, this has not been confirmed in patients. MMAE resistance and MDR1 expression are possible modes of BV resistance for Hodgkin lymphoma both in vitro and in patients.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Blotting, Western; Brentuximab Vedotin; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Hodgkin Disease; Humans; Immunoconjugates; Immunohistochemistry; Inhibitory Concentration 50; Ki-1 Antigen; Lymphoma, Large-Cell, Anaplastic; Oligopeptides; Reverse Transcriptase Polymerase Chain Reaction; Up-Regulation

Peripheral T-cell lymphomas (PTCL), with the exception of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL), have a very poor prognosis. Although current first line chemotherapy continues to be a CHOP-like (cyclophosphamide, doxorubicin, vincristine, prednisone) regimen there is now data suggesting that the addition of etoposide in younger patients improves outcomes. Even for those patients who do have a response to therapy, the risk of relapse remains quite high. Although autologous transplant in first remission is often used, its role as consolidation therapy in first remission remains unclear and may preferentially benefit low-risk patients. In the relapsed setting, major advances have occurred with Food and Drug Administration (FDA) approval of 4 new agents (pralatrexate, romidepsin, belinostat, brentuximab vedotin) for relapsed/refractory PTCL since 2009. These 4 drugs represent the first agents ever approved specifically for this indication. Unfortunately, with the exception of ALCL for which brentuximab vedotin will likely substantially change our approach to treatment, there are still many patients for whom available drugs will not be effective, and it is for these patients that further advances are urgently needed.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Disease-Free Survival; Doxorubicin; Drug Approval; Etoposide; Europe; Humans; International Cooperation; Lymphoma, Large-Cell, Anaplastic; Lymphoma, T-Cell, Peripheral; Medical Oncology; Neoplasm Recurrence, Local; Oligopeptides; Prednisolone; Prognosis; Recurrence; Remission Induction; Risk; Treatment Outcome; United States; United States Food and Drug Administration; Vincristine

Effective antibody-drug conjugates (ADC) combine high drug-linker stability in circulation and efficient intratumoral release of drug. Conjugation of monomethyl auristatin E (MMAE) to the anti-CD30 monoclonal antibody (mAb), cAC10, produced a selective and potent ADC against CD30(+) anaplastic large cell lymphoma and Hodgkin's disease models. This ADC, cAC10-valine-citrulline-MMAE, uses a protease-sensitive dipeptide linker designed to release MMAE by lysosomal cathepsin B in target cells but maintain a stable linkage and attenuate drug potency in circulation. To evaluate ADC stability in vivo, we developed methods for measuring drug/mAb ratios at progressive times in plasma from ADC-treated mice and nonhuman primates. Anti-idiotype mAb permitted the capture and quantitation of mAb cAC10, whereas antidrug mAb and MMAE-conjugated horseradish peroxidase reporter provided quantitative detection of conjugated drug following its in vitro release by cathepsin B. These data were validated by an alternative ELISA using anti-idiotype and anti-MMAE mAbs for capture and detection, respectively. Both methods differentiated ADC with variable levels of drug loading and were subsequently applied to stability studies in severe combined immunodeficient mice and cynomolgus monkeys. Evaluation of ADC from mouse circulation showed the linker half-life to be approximately 144 hours (6.0 days), significantly greater than that reported for disulfide- or hydrazone-linked ADCs in mice or human trials. In cynomolgus monkey, the apparent linker half-life was approximately 230 hours (9.6 days), suggesting that the drug-linker will be highly stable in humans. These data represent the longest reported drug-linker half-life to date and provide the basis for the pronounced specificity and antitumor activity of cAC10-valine-citrulline-MMAE.

Topics: Animals; Antibodies, Anti-Idiotypic; Antibodies, Monoclonal; Disulfides; Drug Stability; Female; Hodgkin Disease; Hydrazones; Immunoconjugates; Ki-1 Antigen; Lymphoma, Large-Cell, Anaplastic; Macaca fascicularis; Mice; Mice, Inbred BALB C; Mice, SCID; Oligopeptides; Sensitivity and Specificity; Tumor Cells, Cultured; Xenograft Model Antitumor Assays