Chicken-derived CD20 antibodies with potent B-cell depletion activity

We report four novel anti-human CD20 (hCD20) monoclonal antibodies (mAbs) discovered from a phylogenetically distant species-chickens. The chicken-human chimaeric antibodies exhibit at least 10-fold enhanced antibody-dependent cellular cytotoxicity (ADCC) and 4-8-fold stronger complement-dependent cytotoxicity (CDC) relative to the clinically used mouse-human chimaeric anti-hCD20 antibody rituximab (RTX). Thus, to our knowledge these mAbs are the first to significantly outperform RTX in both Fc-mediated mechanisms of action. The antibodies show 20-100-fold superior depletion of B cells in whole blood from healthy humans relative to RTX and retain efficacy in vivo. One of the mAbs, AC1, can bind mouse CD20, indicating specificity for a novel hCD20 epitope inaccessible to current (mouse-derived) anti-hCD20 mAbs. A humanized version of one antibody, hAC11-10, was created by complementarity-determining region (CDR) grafting into a human variable region framework and this molecule retained the ADCC, in vitro human whole-blood B-cell depletion, and in vivo lymphoma cell depletion activities of the parent. These mAbs represent promising monotherapy candidates for improving upon current less-than-ideal clinical outcomes in lymphoid malignancies and provide an arsenal of biologically relevant molecules for the development of next-generation CD20-mediated immunotherapies including bispecific T-cell engagers (BiTE), antibody-drug conjugates (ADC) and chimaeric antigen receptor-engineered T (CAR-T) cells.

Immunotherapy in indolent Non-Hodgkin's Lymphoma

Treatment of non-Hodgkin lymphoma (NHL) in general has improved over the years with the emergence of the monoclonal antibodies (MAB) therapy. NHL is divided into B cell NHL and T cell NHL. Treatment of NHL was based on the subtype of NHL and its staging. NHL is divided into aggressive and indolent NHL (iNHL). Subtypes of iNHL include: Follicular lymphoma (FL), Marginal zone lymphoma (MZL), Chronic lymphocytic leukemia/small-cell lymphocytic lymphoma (CLL/SLL), Gastric mucosa-associated lymphoid tissue (MALT) lymphoma, Lymphoplasmacytic lymphoma, Waldenström macroglobulinemia, Nodal marginal zone lymphoma (NMZL), Splenic marginal zone lymphoma (SMZL). Chemotherapy was the main stay treatment of iNHL until the emergence of Rituximab, anti-CD20 MAB targeting CD-20 surface cell antigens that are present on B-cells lymphoma and not on precursor cells, mainly efficacious in B cell iNHL, It became the mainstay treatment in follicular lymphoma (FL) as a single agent modality or in combination with chemotherapy. The anti-CD20 Rituximab played an important role in the development of the treatment of iNHL to become FDA approved in 1997. It was also proven effective in multiple other types of lymphoma. MAB through targeting the cell surface antigen leads to a direct or immune mediated cytotoxicity. This carries few side effects, including allergic reactions. Other than that, a resistance mechanism to rituximab emerged by inducing a failure in the apoptosis mechanism. Alternative mechanisms of resistance included the presence of soluble antigens that could act by binding to the antibody present before the drug itself can bind the lymphoma cell. Thus, the interest in immunotherapy grew further to explore the possibility of conjugating an immune mediated drug to a radio-sensitizing agent in order to enhance the selectivity of the drug. Here came the development of 90Y-ibritumomab tiuxetan and 131I-tositumomab. After it, humanized anti-CD20 emerged ofatumumab, IMMU106 (veltuzumab) in 2005, and ocrelizumab which are considered as second generation anti-CD20 and 3^rd generation anti-CD20 include AME-133v (ocaratuzumab), PRO131921 and GA101 (obinutuzumab). Also multiple other agents emerged targeting different surface cell antigens like CD52 (alemtuzumab), CD22 (unconjugated epratuzumab and calicheamicin conjugated CMC-544 [inotuzumab ozogamicin]), CD80 (galiximab), CD2 (MEDI-507 [siplizumab]), CD30 (SGN-30 and MDX-060 [iratumumab], Brentuximab vedotin), CD40 (SGN-40), and CD79b (Polatuzumab). Other agents include MAB targeting T-Cells like mogamulizumab, Denileukin Diftitox and BiTEs or bispecific T cell engagers like Mosunetuzumab, Glofitamab, and Epcoritamab. Moreover, further studies came up to evaluate the role of immunotherapy in combination chemotherapy as a pathway to evade the resistance mechanisms. Side effects of the treatment were mainly infusion related adverse reactions, myelosuppression in conjugated forms leading to immunosuppression and subsequently to infectious complications. Another important aspect in immunotherapy is the half-lives of the medication which is an important factor that can influence the evaluation of the response. The MAB treatment showed important benefit in the treatment of iNHL and it continuously shows how rapidly it can develop to provide optimum care and benefit to patients with iNHL.

Incidence and time trends of second primary malignancies after non-Hodgkin lymphoma: a Swedish population-based study

We observed stable excess rates of secondary malignancies over time among lymphoma patients compared with the general population.

In follicular lymphoma, decreasing rates of secondary myelodysplastic syndrome and acute myeloid leukemia were observed after 2009.

Considering treatment changes and an improved prognosis of non-Hodgkin lymphoma (NHL) over time, knowledge regarding long-term health outcomes, including late effects of treatment, has become increasingly important. We report on time trends of second primary malignancies (SPMs) in Swedish NHL patients, encompassing the years before as well as after the introduction of anti-CD20 antibody therapy. We identified NHL patients in the Swedish Cancer Register 1993 to 2014 and matched comparators from the Swedish Total Population Register. The matched cohort was followed through 2017. By linking to the Swedish Lymphoma Register, subcohort analyses by NHL subtype were performed. Flexible parametric survival models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) of SPM among patients and comparators. Among 32 100 NHL patients, 3619 solid tumors and 217 myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) cases were observed, corresponding to a 40% higher rate of solid tumors (HR_{solid tumors} = 1.4; 95% CI, 1.4-1.5) and a 5-fold higher rate of MDS/AML (HR_MDS/AML = 5.2; 95% CI, 4.4-6.2) than for comparators. Overall, the observed excess risks for solid tumors or MDS/AML remained stable over the study period, except for follicular lymphoma, where the excess rate of MDS/AML attenuated with time (P for trend = .012). We conclude that NHL survivors have an increased risk of both solid tumors and hematologic malignancies, in particular MDS/AML. Stable excess risks over time indicate that contemporary treatment standards are not associated with modified SPM risk. Encouragingly, decreasing rates of MDS/AML were noted among patients with follicular lymphoma, possibly due to the increasing use of nonchemotherapy-based treatments.

Retrospective analysis of the preparation and application of immunotherapy in cancer treatment (Review)

Monoclonal antibody technology plays a vital role in biomedical and immunotherapy, which greatly promotes the study of the structure and function of genes and proteins. To date, monoclonal antibodies have gone through four stages: murine monoclonal antibody, chimeric monoclonal antibody, humanised monoclonal antibody and fully human monoclonal antibody; thousands of monoclonal antibodies have been used in the fields of biology and medicine, playing a special role in the pathogenesis, diagnosis and treatment of disease. In this review, we compare the advantages and disadvantages of hybridoma technology, phage display technology, ribosome display technology, transgenic mouse technology, single B cell monoclonal antibody generation technologies, and forecast the promising applications of these technologies in clinical medicine, disease diagnosis and tumour treatment.

Role of 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography Imaging in the Prediction of Prognosis in Patients With Indolent Lymphoma: Prospective Study

BACKGROUND

The role of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in indolent lymphoma has been minimally studied.

OBJECTIVE

This study aims to assess the value of FDG-PET/CT in predicting the prognosis of indolent lymphoma.

METHODS

We prospectively recruited 42 patients with indolent lymphoma. A total of 2 patients were excluded, and 40 underwent baseline PET/CT and follow-up at various time points. A total of 9 patients were observed only, 7 received 4 doses of rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using the maximum standardized uptake value (SUVmax) and Deauville criteria (DC). We aimed to obtain the best SUVmax and DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from the initial diagnosis was 33.83 months.

RESULTS

SUVmax <4.35 at interim PET/CT provided the best discrimination, with a progression-free survival (PFS) of 100% and a median survival time of 106.67 months compared with SUVmax ≥4.35 (P=.04), which had a PFS of 43.8% and a median survival time of 50.17 months. This cutoff was also valuable in predicting overall survival at baseline, that is, 100% overall survival with baseline SUVmax <4.35, versus 58.4% for SUVmax ≥4.35 (P=.13). The overall survival of patients with a baseline DC score <3.0 was 100%, with a median overall survival of 106.67 months.

CONCLUSIONS

We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (<4.35 vs ≥4.35) on interim PET/CT performed best in predicting PFS.

Prolonged rituximab maintenance in follicular lymphoma patients: long-term results of the SAKK 35/03 randomized trial

The Swiss Group for Clinical Cancer Research (SAKK) conducted the SAKK 35/03 randomized trial (NCT00227695) to investigate different rituximab monotherapy schedules in patients with follicular lymphoma (FL). Here, we report their long-term treatment outcome. Two-hundred and seventy FL patients were treated with 4 weekly doses of rituximab monotherapy (375 mg/m2); 165 of them, achieving at least a partial response, were randomly assigned to maintenance rituximab (375 mg/m2 every 2 months) on a short-term (4 administrations; n = 82) or a long-term (up to a maximum of 5 years; n = 83) schedule. The primary end point was event-free survival (EFS). At a median follow-up period of 10 years, median EFS was 3.4 years (95% confidence interval [CI], 2.1-5.5) in the short-term arm and 5.3 years (95% CI, 3.5-7.5) in the long-term arm. Using the prespecified log-rank test, this difference is not statistically significant (P = .39). There also was not a statistically significant difference in progression-free survival or overall survival (OS). Median OS was 11.0 years (95% CI, 11.0-NA) in the short-term arm and was not reached in the long-term arm (P = .80). The incidence of second cancers was similar in the 2 arms (9 patients after short-term maintenance and 10 patients after long-term maintenance). No major late toxicities emerged. No significant benefit of prolonged maintenance became evident with longer follow-up. Notably, in symptomatic patients in need of immediate treatment, the 10-year OS rate was 83% (95% CI, 73-89%). These findings indicate that single-agent rituximab may be a valid first-line option for symptomatic patients with advanced FL.

Targeting CD205 with the antibody drug conjugate MEN1309/OBT076 is an active new therapeutic strategy in lymphoma models

Antibody drug conjugates represent an important class of anti-cancer drugs in both solid tumors and hematological cancers. Here, we report preclinical data on the anti-tumor activity of the first-in-class antibody drug conjugate MEN1309/OBT076 targeting CD205. The study included preclinical in vitro activity screening on a large panel of cell lines, both as single agent and in combination and validation experiments on in vivo models. CD205 was first shown frequently expressed in lymphomas, leukemias and multiple myeloma by immunohistochemistry on tissue microarrays. Anti-tumor activity of MEN1309/OBT076 as single agent was then shown across 42 B-cell lymphoma cell lines with a median IC50 of 200 pM and induction of apoptosis in 25/42 (59.5%) of the cases. The activity appeared highly correlated with its target expression. After in vivo validation as the single agent, the antibody drug conjugate synergized with the BCL2 inhibitor venetoclax, and the anti-CD20 monoclonal antibody rituximab. The first-in-class antibody drug targeting CD205, MEN1309/OBT076, demonstrated strong pre-clinical anti-tumor activity in lymphoma, warranting further investigations as a single agent and in combination.

Lenalidomide: A Review in Previously Treated Follicular Lymphoma

Lenalidomide (Revlimid^®) is a targeted immunomodulatory drug with multiple mechanisms of action. In the USA and the EU, oral lenalidomide is indicated in combination with rituximab or a rituximab product for the treatment of patients with previously treated follicular lymphoma. In the pivotal, phase III AUGMENT trial, lenalidomide + rituximab significantly prolonged progression-free survival (PFS; primary endpoint) relative to placebo + rituximab in patients with relapsed or refractory indolent non-Hodgkin lymphoma, with the PFS benefit appearing to be specific to patients with follicular lymphoma and extending to elderly patients with this subtype. Lenalidomide + rituximab also demonstrated activity in an interim analysis of the phase III MAGNIFY trial in patients with relapsed or refractory indolent non-Hodgkin lymphoma, including those with rituximab-refractory disease. Lenalidomide had an acceptable tolerability profile. Although grade 3 or 4 neutropenia occurred more frequently with lenalidomide + rituximab than with placebo + rituximab, this was generally well managed with dosage adjustments and growth factor support. In conclusion, lenalidomide in combination with rituximab represents an important new treatment option for previously treated follicular lymphoma, including patients whose disease has become refractory to rituximab.

A phase I study of the PD-L1 inhibitor, durvalumab, in combination with a PARP inhibitor, olaparib, and a VEGFR1-3 inhibitor, cediranib, in recurrent women's cancers with biomarker analyses

BACKGROUND

Strategies to improve activity of immune checkpoint inhibitors are needed. We hypothesized enhanced DNA damage by olaparib, a PARP inhibitor, and reduced VEGF signaling by cediranib, a VEGFR1-3 inhibitor, would complement anti-tumor activity of durvalumab, a PD-L1 inhibitor, and the 3-drug combination would be tolerable.

METHODS

This phase 1 study tested the 3-drug combination in a 3 + 3 dose escalation. Cediranib was taken intermittently (5 days on/2 days off) at 15 or 20 mg (dose levels 1 and 2, respectively) with durvalumab 1500 mg IV every 4 weeks, and olaparib tablets 300 mg twice daily. The primary end point was the recommended phase 2 dose (RP2D). Response rate, pharmacokinetic (PK), and correlative analyses were secondary endpoints.

RESULTS

Nine patients (7 ovarian/1 endometrial/1 triple negative breast cancers, median 3 prior therapies [2-6]) were treated. Grade 3/4 adverse events include hypertension (1/9), anemia (1/9) and lymphopenia (3/9). No patients experienced dose limiting toxicities. The RP2D is cediranib, 20 mg (5 days on/2 days off) with full doses of durvalumab and olaparib. Four patients had partial responses (44%) and 3 had stable disease lasting ≥6 months, yielding a 67% clinical benefit rate. No significant effects on olaparib or cediranib PK parameters from the presence of durvalumab, or the co-administration of cediranib or olaparib were identified. Tumoral PD-L1 expression correlated with clinical benefit but cytokines and peripheral immune subsets did not.

CONCLUSIONS

The RP2D is tolerable and has preliminary activity in recurrent women's cancers. A phase 2 expansion study is now enrolling for recurrent ovarian cancer patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02484404. Registered June 29, 2015.

Short regimen of rituximab plus lenalidomide in follicular lymphoma patients in need of first-line therapy

The SAKK 35/10 phase 2 trial, developed by the Swiss Group for Clinical Cancer Research and the Nordic Lymphoma Group, compared the activity of rituximab vs rituximab plus lenalidomide in untreated follicular lymphoma patients in need of systemic therapy. Patients were randomized to rituximab (375 mg/m² IV on day 1 of weeks 1-4 and repeated during weeks 12-15 in responding patients) or rituximab (same schedule) in combination with lenalidomide (15 mg orally daily for 18 weeks). Primary end point was complete response (CR)/unconfirmed CR (CRu) rate at 6 months. In total, 77 patients were allocated to rituximab monotherapy and 77 to the combination (47% poor-risk Follicular Lymphoma International Prognostic Index score in each arm). A significantly higher CR/CRu rate at 6 months was documented in the combination arm by the investigators (36%; 95% confidence interval [CI], 26%-48% vs 25%; 95% CI, 16%-36%) and confirmed by an independent response review of computed tomography scans only (61%; 95% CI, 49%-72% vs 36%; 95% CI, 26%-48%). After a median follow-up of 4 years, significantly higher 30-month CR/CRu rates and longer progression-free survival (PFS) and time to next treatment (TTNT) were observed for the combination. Overall survival (OS) rates were similar in both arms (≥90%). Toxicity grade ≥3 was more common in the combination arm (56% vs 22% of patients), mainly represented by neutropenia (23% vs 7%). Addition of lenalidomide to rituximab significantly improved CR/CRu rates, PFS, and TTNT, with expected higher, but manageable toxicity. The excellent OS in both arms suggests that chemotherapy-free strategies should be further explored. This trial was registered at www.clinicaltrials.gov as #NCT01307605.

EZH2/Bcl-2 Coexpression Predicts Worse Survival in Diffuse Large B-cell Lymphomas and Demonstrates Poor Efficacy to Rituximab in Localized Lesions

Enhancer of zeste homolog 2 (EZH2) and Bcl-2 gene rearrangement or protein upregulation played pivotal roles in the carcinogenesis of various malignancies including lymphomas. However, EZH2/Bcl-2 expression pattern and its clinicopathologic/prognostic significance in diffuse large B-cell lymphoma (DLBCL) remain unclear. To identify the association among EZH2, Bcl-2, clinicopathologic parametres in DLBCL, 2 DLBCL patient sets (test cohort, n=85; validation cohort n=51) and DLBCL cell lines were studied by tumor tissue microarray (TMA), immunohistochemistry and western blot. The optimal cut-off of EZH2 was determined by X-tile program from test cohort, as was verified in validation cohort. The prognostic significance was determined via Kaplan-Meier survival estimates and log-rank tests. Consequently, EZH2 and Bcl-2 expression were both enhanced and positively correlated with each other (𝑃=0.001) in both DLBCL patients and cell lines. EZH2/Bcl-2 coexpression was associated with poor overall survival (OS) and progression-free survival (PFS) in all DLBCL patients (all P<0.05). Univariate analyses revealed that EZH2/Bcl-2 coexpression correlated to worse objective response rate (ORR), shorter OS and PFS in DLBCL patients treated with RCHOP while multivariate analysis indicated that only elevated LDH level (P=0.001) and presence of B symtom (P=0.008) rather than EZH2/Bcl-2 coexpression were associated with worse OS. No survival benefit from rituximab regimen had been demonstrated in the early-staged DLBCL patients with EZH2/Bcl-2 coexpression. While in the subgroup of III-IV stage, RCHOP regimen showed obvious better OS and PFS than CHOP (P=0.039 and 0.005). In conclusion, EZH2/Bcl-2 coexpression defines unrecognized subgroup of DLBCL patients with distinct epigenetic phenotype and worse outcome.

The novel CD19-targeting antibody-drug conjugate huB4-DGN462 shows improved anti-tumor activity compared to SAR3419 in CD19-positive lymphoma and leukemia models

Antibody-drug conjugates (ADC) are a novel way to deliver potent cytotoxic compounds to cells expressing a specific antigen. Four ADC targeting CD19, including SAR3419 (coltuximab ravtansine), have entered clinical development. Here, we present huB4-DGN462, a novel ADC based on the SAR3419 anti-CD19 antibody linked via sulfo-SPDB to the potent DNA-alkylating agent DGN462. huB4-DGN462 had improved in vitro anti-proliferative and cytotoxic activity compared to SAR3419 across multiple B-cell lymphoma and human acute lymphoblastic leukemia cell lines. In vivo experiments using lymphoma xenografts models confirmed the in vitro data. The response of B-cell lymphoma lines to huB4-DGN462 was not correlated with CD19 expression, the presence of BCL2 or MYC translocations, TP53 inactivation or lymphoma histology. In conclusion, huB4-DGN462 is an attractive candidate for clinical investigation in patients with B-cell malignancies.