bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of a phase I study of DTS-201, a peptidic prodrug of doxorubicin, in patients with solid tumors
Authors: Delord J. , Schöffski P. , Brain E. , Dumez H. , Robert J. , Faivre S. , Dubois V. , Vialatte K. , Deshayes J. , Ravel D.
Published: March 2020

2547

Background: DTS-201 is a promising prodrug of doxorubicin (dox) designed to preferentially deliver the parent compound to tumor cells and to limit cardiotoxicity. Based on animal studies showing that DTS-201 was markedly safer and more active than conventional dox, a phase I trial was conducted to determine safety, pharmacokinetics and the recommended dose (RD) for phase II studies. Methods: DTS-201 was given as 1-hour infusion every 3 weeks. Four dose levels were tested: 80, 160, 250 and 400 mg/m2 equivalent to 45 to 225 mg dox/m2. Toxicity was evaluated according to CTCAE v3.0 with specific attention to cardiotoxicity assessed by troponin I, echocardiography or cardio MUGA scan and 12-lead ECG. Results: Nineteen cancer patients (pts) with solid tumors (age range: 30–72 yrs) received DTS-201. Tolerance was good at 80 and 160 mg/m2. Three dose limiting toxicities (DLTs) were observed at cycle 1, one at 250 mg/m2 (grade 3 diarrhea) and two at 400 mg/m2 (one grade 3 vomiting and one grade 4 neutropenia = 5 days). Myelosuppression was the most common toxicity with 5 of the 6 pts treated at 400 mg/m2 experiencing transient asymptomatic grade 3–4 neutropenia on day 15 that spontaneously resolved. Other adverse reactions included mild to moderate asthenia, alopecia, anorexia and nausea. Neither cardiotoxicity or dox unrelated toxicities were observed. Disease stabilization for more than 4 cycles was observed in three pts with prostate cancer, pleural mesothelioma or bronchoalveolar carcinoma at 250 and 400 mg/m2. The pt with prostate cancer treated at 250 mg/m2 experienced a 60% decrease in serum PSA and a 23% reduction in lymph node size. The plasma AUCs and Cmax for DTS-201 and dox increased linearly with dose. At 400 mg/m2, the AUC of dox was within the range of values observed in pts receiving 60 mg/m2 of conventional dox. However the Cmax of dox, observed at 1 to 1.5 hours following DTS-201 administration, was 20 to 25 times lower. Conclusion: DTS-201 was well tolerated up to 400 mg/m2, corresponding to 3.750-fold the standard dose of dox. This dose, with no evidence of cardiac toxicity, was proposed to be the RD for future phase II studies. Six additional pts will be treated at that dose level to better characterize safety.

No significant financial relationships to disclose.
Phase I clinical and pharmacokinetic (PK) trial of the kinesin spindle protein (KSP) inhibitor MK-0731 in patients with solid tumors
Authors: Stein M. N. , Tan A. , Taber K. , Fernandez R. , Agrawal N. G. , Vandendries E. , Hsu K. , Walker A. , Holen K. , Wilding G.
Published: March 2020

2548

Background: KSP is essential for the separation of spindle poles during mitosis and inhibition results in mitotic arrest. MK- 0731 is a potent inhibitor of KSP, with an IC50 of 2.2 nM, and >20,000 fold selectivity against other kinesins. MK-0731 causes mitotic arrest with an EC50 in several tumor cell lines of 3–5 nM. Methods: Phase I study to determine the safety and tolerability, MTD, and PK of MK-0731 administered IV over 24 hrs every 21 days. In part 1, dosing started at 6 mg/m2/24 hr and was escalated until the MTD was reached. In part 2, pts with measurable taxane-resistant cancer were treated at the MTD established in Part 1 (target accrual =22 pts in part 2). Interim Results: 35 pts with solid tumors (M/F 23/12), median age 63 yrs (23 - 79), were treated at doses of 6 to 48 mg/ m2/24hrs (median cycles 3, range 1–10, total cycles=128). Frequent tumor types included prostate (8), ovarian (4), colon (3), bladder (2), neuroendocrine (2), lung (2), breast (2). Prolonged (>5 days) grade 4 neutropenia was observed in 2 pts at 48 mg/m2/24hrs (11 days duration) and 2 pts at 24 mg/m2/24hrs (7 days duration) leading to expansion of cohorts at lower dose levels. At the MTD of 17 mg/ m2/24, there were no DLTs. 14 patients have been enrolled at the MTD in part 2 of the study. Drug related grade 3/4 toxicities were anemia (1), AST (1), hyperglycemia (1), nausea/vomiting (1), neutropenia (7), syncope (1). PK results from the first 20 patients suggest that MK- 0731 concentrations appear to decline monoexponentially or biexponentially following the infusion with terminal t1/2 from ∼4 to 22 hrs. In some patients, steady-state concentrations may not be achieved by the end of the 24 hr infusion. Mean values at the 17 mg/m2/24hrs dose level were Cmax=599 nM, AUC8=14.56 μM·hr, and CL=119 mL/min. AUC, exposures, and end of infusion concentrations appear to increase proportionally with dose. Stable disease for = 4 cycles (range 4- 10) was seen in 16 patients. Conclusion: Treatment with MK-0731 at the MTD of 17 mg/m2/day every 21 days in patients with advanced solid tumors was well tolerated with consistent dose limiting toxicity of myelosuppression.

No significant financial relationships to disclose.
Elucidating the mechanisms responsible for the previous failure of phase III clinical trials with eniluracil (EU) and development of a novel scheduling approach to optimize the efficacy of EU/5-fluorouracil (5-FU) combination therapy
Authors: Guarcello V. , Fourie J. , Lawton M. J. , Peters W. W. , Heslin M. J. , Diasio R. B.
Published: March 2020

2557

Background: Irreversible inhibition of dihydropyrimidine dehydrogenase (DPD) by EU blocks 5-FU catabolism allowing for oral 5-FU administration with complete bioavailability. Unfortunately, phase III trials with co-administered EU/5-FU showed inferiority vs. 5-FU/leucovorin, and were discontinued. We recently reported that competitive inhibition of human uridine phosphorylase (UP) and thymidine phosphorylase (TP) 5-FU-anabolic enzymes by EU is an important mechanism potentially responsible for clinical failure of the combined EU/5- FU regimen. We hypothesize that EU inhibition of UP and TP is transient, while that of DPD is prolonged, allowing for novel schedule dependent optimization of EU/5-FU dosing regimens with improved efficacy. Methods: In this phase I study, five patients received a single oral dose (2 mg, 5 mg or 10 mg) of EU 12–14 hours prior to scheduled resection of primary/metastatic colorectal cancer. Dosage was as follows: Two patients received the 2 mg dose, one patient received the 5 mg dose and two patients received the 10 mg dose. Matched normal and tumor tissue biopsies were immediately snap frozen and subsequently UP, TP and DPD activity was measured in vitro via HPLC detection of [6- 14C]-5-FU catabolites/anabolites. Peripheral blood mononuclear cell (PBMC) DPD activity was determined at baseline prior to EU administration, 30 min prior to surgery (Day 1), and on Days 2, 5 and 14 following EU administration. Results: At 12–14 hours following EU administration, there was an absence of inhibition of UP and TP, while DPD was significantly inhibited in matched tumor and normal tissue. Importantly, PBMC DPD activity was significantly inhibited by EU on Day 1 (12–14 hours after EU administration) and Day 2 (36 hours after EU administration) at 0 ± 0% and 17 ± 11% (mean ± SD) of baseline, respectively. Conclusions: These data demonstrate a differential recovery time of EU mediated inhibition of UP and TP compared to DPD, which permits future schedule dependent optimization of EU/5-FU therapy.

No significant financial relationships to disclose.
A phase I study of TPI 287, a third generation taxane, administered every 21 days in patients with advanced cancer
Authors: Modiano M. , Plezia P. , Baram J. , Catane R. , Cohn A. , Basche M. , Kurman M. , Tapolsky G. , Yancik S.
Published: March 2020

2569

Background: TPI 287 is a third generation taxane engineered to overcome multi-drug resistance and to bind to mutant tubulin. In preclinical studies, TPI 287 suppressed the growth of multiple human tumor xenografts in nude mice, including xenografts that expressed mdr- 1 and that were resistant to other taxanes. The safety and tolerability of TPI 287 when administered every 21 days was examined in this Phase 1 dose escalation study in patients (pts) with advanced neoplasms. Methods: TPI 287 was administered over 1 hour every 21 days in ascending doses to groups of 3 pts. Treatment cohorts were expanded to 6 pts in the face of dose-limiting toxicity (DLT); pts could remain on study until the development of progressive disease or an intolerable adverse event. DLT was defined as Gr 4 heme toxicity lasting 7 days; febrile neutropenia, Gr 3 thrombocytopenia with bleeding, Gr 3 elevation of transaminases lasting 7 days or any other Gr 3/4 toxicity other than nausea or vomiting. Results: 14 pts (M:F 5:9, median age 58.5, range 49 - 77) were enrolled in 5 dose levels ranging from 56 - 185 mg/m2. Pts’ cancers included colorectal (5 pts), esophageal (2), pancreatic (2), NSCLC (2), breast (2) and ovarian (1). All patients had received prior chemotherapy (median no. prior treatments: 3 (range, 2 - 10). Drug related adverse events included mucositis, vomiting, diarrhea, neutropenia, thrombocytopenia, myalgias and peripheral neuropathy. Only 1 pt. experienced Gr 4 neutropenia. DLT of Gr 3 peripheral sensory neuropathy was observed at a dose of 185 mg/m2. At a dose of 160 mg/m2 no DLT was observed. 1 pt with pancreatic cancer had a confirmed response to TPI 287 that has persisted for 2.5 months and continues as of this writing. PK data reveal that AUC is generally dose linear. At a dose of 126 mg/m2, clearance was 24.7 + 12.2 L/hr/m2 and t1/2 was 10.6 + 7.1 hrs. Conclusions: TPI 287 can be safely administered in a dose of 160 mg/m2 every 21 days. The dose limiting toxicity was Gr 3 peripheral neuropathy. Anti-neoplastic activity was seen in a patient with pancreatic cancer. PK is dose linear and predictable. Several Phase 2 studies of TPI 287 are being planned.

No significant financial relationships to disclose.
A phase I pharmacokinetic and pharmacodynamic study of AMG 479, a fully human monoclonal antibody against insulin-like growth factor type 1 receptor (IGF-1R), in advanced solid tumors
Authors: Tolcher A. W. , Rothenberg M. L. , Rodon J. , Delbeke D. , Patnaik A. , Nguyen L. , Young F. , Hwang Y. , Haqq C. , Puzanov I.
Published: March 2020

3002

Background: Increased IGF-1 signaling mediates tumor proliferation, reduces apoptosis, and correlates with higher incidence and progression of common cancers. AMG 479, a fully human monoclonal antibody against IGF-1R, exhibited broad antitumor activity in xenograft models, both as a monotherapy and with chemotherapy. Methods: Patients (pts) entered escalating dose cohorts of AMG 479 (from 1 to 20 mg/kg administered intravenously [IV] every two weeks [Q2W]). Study objectives were to determine safety, maximum tolerated dose (MTD), pharmacokinetic (PK) parameters, pharmacodynamic (PD) parameters of tumor glucose metabolism (FDG PET/CT), human anti- AMG 479 antibody formation, IGF-1R occupancy in neutrophils, and tumor response (CT RECIST, and PET/CT criteria). Results: Sixteen pts with advanced malignancies were treated with doses from 1 to 20 mg/kg. The median number of cycles was 3 (range 1 to 16). Grade 3 thrombocytopenia was considered dose limiting in 1 pt at 20 mg/kg. Other grade 3/4 non-hematologic toxicities were observed in 2 pts; no hyperglycemia greater than grade 2 was observed. Anti-AMG 479 antibodies, but not neutralizing antibodies, were detected in 1 pt. One pt had an infusion reaction (grade 2 chills/rigors resolving in 15 minutes) but could be retreated following premedication. AMG 479 exhibited dose-linear PK in the dose range from 1 to 20 mg/kg, reaching steady state after 3 doses; mean terminal t1/2 ranged from 7 to 11 days; mean serum clearance ranged from 9 to 14 mL/day/kg; Css exceeded IC90 measured in preclinical models. PD results indicated a trend to dose-proportional occupancy of IGF-1R in neutrophils and increased levels of serum IGF-1 and IGF-BP3 (40% and 20% on day 3, respectively). By CT RECIST criteria, 1 pt with a neuroendocrine tumor had a confirmed partial response and 5 pts had durable stable disease. By FDG-PET/CT criteria, 1 pt with breast cancer had a mixed response. Conclusions: AMG 479 appears to be well tolerated at doses up to 20 mg/kg IV Q2W; dose escalation is complete. AMG 479 administration resulted in PK values adequate for activity in preclinical models, saturable binding of IGF-1R in neutrophils, and preliminary anti-tumor activity.

[Table: see text]
Clinical and immunologic effects of a HER2/neu (E75) peptide vaccine booster in previously vaccinated breast cancer patients
Authors: Holmes J. P. , Amin A. , Storrer C. E. , Smith A. M. , Jama Y. H. , McNeil A. , Craig D. , Ponniah S. , Peoples G. E.
Published: March 2020

3014

Background: We are conducting clinical trials of the HER2/neu E75-peptide vaccine in clinically disease-free breast cancer (BCa) patients. Our Phase I/II trials have shown that the E75+GM-CSF vaccine is safe and effective in stimulating clonal expansion of E75-specific CD8+ T-cells. Since peptide vaccines may not lead to long term immunity, we have assessed the need for and response to a vaccine booster for patients after completion of their primary vaccination series. Methods: BCa patients enrolled in our E75 vaccine trials who were >6 months from the completion of their primary vaccination series were offered a single 1000 mcg dose of E75 peptide with 250 mcg of GM-CSF. Patients were monitored for local and systemic toxicity. E75-specific CD8+ T-cells were quantified using the HLA-A2:IgG dimer before and after booster administration. Results: 19 patients have received the vaccine booster. Median time from primary vaccine series was 12 months (range 6–25) and median residual E75-specific immunity was 0.61% (range 0- 3.43%). Significant residual immunity (SRI=CD8+ E75-specific T-cells >0.5%) was seen in 71% of patients <12 months from primary vaccination vs. 33% of patients ≥12 months. Graded local toxicities were as follows: 18/19 (94.7%) grade 1; 1/19 (5.3%) grade 2. Only 6/19 (31.6%) experienced even grade 1 systemic toxicity. Local reactions were more robust in patients receiving the booster <12 months from primary vaccine compared to those ≥12 months (99±2.8 mm vs. 75±1 mm, p=0.01). In patients lacking SRI, 80% showed increased specific immunity post-vaccination. In these patients, the average CD8+ E75-specific T-cells pre-booster vs. post-booster was 0.37±0.03% vs. 1.06 ± 0.14% (p=0.07). Conclusions: The HER2/neu peptide vaccine E75 stimulates specific immunity in disease-free BCa patients. However, only about half of patients show SRI at median follow-up of 12 months. A vaccine booster is safe and highly effective in stimulating E75-specific immunity especially in those patients without SRI. Initial results suggest that the booster should be given within a year of completion of the initial vaccine series.

No significant financial relationships to disclose.
VEGF kinoid vaccine, a therapeutic arm against tumor angiogenesis and metastases
Authors: Ritsou E. , Le Buanec H. , Haghighi Rad F. , Larcier P. , Zagury D. , Uzan G.
Published: March 2020

3018

Background: Vascular endothelial growth factor (VEGF) plays a central role in neoangiogenesis and thus represents an important therapeutic target in antiangiogenic cancer therapy strategies. We have developed an anti-VEGF vaccine VEGF kinoid that elicits high titres of neutralizing anti-VEGF antibodies in mice. In this study we have evaluated the immunogenicity, safety and efficacy of VEGF kinoid in preventing tumor growth and metastases in mice. Methods: The efficacy of VEGF kinoid was evaluated in a model of active immunization (CT26 colon carcicoma lung metastases model) and in two models of passive immunization. On the passive immunization setting two VEGF secreting xenograft tumor models, A673 rhabdomyosarcoma and HT29 colon carcinoma, were used to evaluate the ability of IgGs derived from kinoid immunized mice to inhibit tumor growth in comparison with bevacizumab. Results: Active immunization with autologous VEGF Kinoid (mVEGF kinoid) triggered a strong anti-VEGF antibody but no cellular immune response in mice. The anti-VEGF Abs exhibited high neutralizing capacity as assessed via inhibition of human umbilical vein endothelial cell proliferation in the presence of VEGF and binding to the Flk-1 receptor. In mVEGF kinoid immunized BALB/c mice challenged with syngeneic CT26 colorectal tumor cells the lung metastases were inhibited. In human VEGF (hVEGF) kinoid immunized Balb/c mice neutralizing anti-hVEGF Abs were elicited. Purified IgG from these mice inhibited tumor growth of human A673 rhabdomyosarcoma and HT29 colon carcinoma cells xenografted in Swiss nude and NOD/SCID mice respectively as assessed by T/C% measurements. Tumor cell growth inhibition was similar to that in mice receiving therapeutic doses of bevacizumab. Active immunization against VEGF showed an excellent safety profile in mice and no impairment of would healing processes was observed after surgical interventions in immunized mice. Conclusions: These experiments show that active immunization with VEGF kinoid elicits polyclonal neutralizing anti-VEGF Abs that inhibit metastases and tumor growth in mice. It may thus represent an alternative strategy to safely combat VEGF-dependent neovascularization and metastases occurring in malignant tumors.

No significant financial relationships to disclose.
Immunomonitoring results of a pivotal phase II/III study with the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) in ovarian cancer patients with malignant ascites
Authors: Jaeger M. J. , Schoberth A. M. , Heiss M. M. , Lahr A. , Lindhofer H.
Published: March 2020

3020

Background: Malignant ascites is a symptom of late-stage tumor disease and associated with a poor prognosis. The trifunctional antibody catumaxomab specifically binds to EpCAM+ tumor cells and redirects CD3+ T lymphocytes and FcγR I/III+ accessory cells simultaneously to the tumor site. Methods: 129 (85 catumaxomab; 44 control paracentesis) EpCAM-positive ovarian cancer patients with symptomatic malignant ascites were compared in an open-label, multicenter, randomized study for efficacy and tolerability of intraperitoneally given catumaxomab. Various in vivo and in vitro immunological and pharmacodynamic parameters were measured directly from ascites cell preparations. Results: During the course of catumaxomab treatment in the ascites fluid tumor cells dramatically decreased and leukocytes increased. Accordingly, the in vivo effector/target ratio (CD45+/EpCAM+) showed an drastic increase from a baseline of 6:1 to 10,000:1 already after the first infusion (all median). Leukocyte expansion was accompanied by in vivo upregulation of T cell activation marker CD69 on CD4+ and CD8+ T cells in the ascites fluid and an increase of IL-6 in serum at 24 hours after each infusion indicating systemic effects of catumaxomab. In vitro pharmacodynamic studies were carried out with screening samples to further validate the in vivo results. Similarly, the in vitro experiments showed efficient EpCAM+ tumor cell elimination, leukocyte expansion, drastical improvement of the effector/target ratio and activation of T cells. Additionally, a strong upregulation of activating cytokines IL-2 and IFN-γ (TH1 cytokine profile) and proliferation of CD4+, CD8+ T cells and CD11c+ accessory cells were demonstrated in the samples with catumaxomab compared to controls. Conclusions: Intraperitoneal catumaxomab treatment triggers activation and proliferation of different immune cells and leads to elimination of tumor cells within malignant ascites. These data confirm the postulated mode of action of trifunctional catumaxomab in vivo and correlate with clinical efficacy in patients with malignant ascites.

[Table: see text]
Safety and efficacy of eculizumab with concomitant erythropoietin therapy in patients with paroxysmal nocturnal hemoglobinuria (PNH)
Authors: Mojcik C. F. , Young N. S. , Luzzatto L. , Socié G. , Hillmen P. , Brodsky R. A.
Published: March 2020

3032

Background: Erythropoietins (EPO) are commonly used to improve anemia in patients with bone marrow failure syndromes and in patients with chemotherapy-induced anemia. Two recent phase 3 clinical studies have demonstrated significant benefit of the terminal complement inhibitor, eculizumab (Soliris), in a heterogeneous population of patients with the acquired clonal hemolytic and bone marrow failure disorder, PNH (n=140). While previous studies have shown that EPO is associated with only moderate improvements in fatigue in anemic cancer patients (effect size of 0.5), eculizumab has demonstrated large improvements in fatigue in PNH patients (effect size of 1.1). Methods: To investigate whether eculizumab provides further benefit to PNH patients receiving EPO, efficacy parameters were examined in the EPO subpopulation (n=8). Results: Intravascular hemolysis, as assessed by plasma levels of lactate dehydrogenase (LDH) area under the curve, was reduced 268,271 U/L x day to near normal levels in EPO-treated patients during 26 weeks of eculizumab therapy (p=0.008, signed rank test). Anemia was improved as packed RBC transfusion requirements were substantially reduced with eculizumab in EPO patients from a median of 7.5 units per patient in the 6 months before treatment to 1 unit per patient during eculizumab treatment (p=0.031, signed rank test). Despite pre-existing EPO and transfusion support, eculizumab treatment markedly improved fatigue with a 7.3 point increase over baseline using the FACIT-fatigue instrument (p=0.016, signed rank test; a 3 or more point increase in this instrument has been shown to be clinically meaningful). Eculizumab was well tolerated when administered to PNH patients treated with concomitant EPO with adverse events similar to the overall population. The significant clinical improvements in hematologic and quality of life outcomes with eculizumab treatment in PNH patients receiving concomitant EPO were similar to the clinical improvements demonstrated in the overall PNH patient population. Conclusions: These analyses show that eculizumab treatment provides important clinical benefit when administered to PNH patients receiving EPO support for bone marrow failure.

No significant financial relationships to disclose.
A phase II study of the anti-CTLA4 monoclonal antibody (mAb), CP-675,206, in patients with refractory metastatic adenocarcinoma of the colon or rectum
Authors: Chung K. Y. , Gore I. , Fong L. , Venook A. , Dorazio P. , Healey D. , Pavlov D. , Saltz L. B.
Published: March 2020

3035

Background: The antitumor activity of antibodies to cytotoxic T lymphocyte-associated antigen 4 (CTLA4) has been demonstrated in a variety of murine tumor models, including rejection of established tumors and secondary exposure to tumor cells. This suggests that blockade of the inhibitory effects of CTLA4 can promote effective antitumor immune responses. CP-675,206 has also been shown to induce durable tumor responses in patients (pts) with metastatic melanoma in phase 1 and phase 2 clinical studies. The purpose of this study was to assess safety and efficacy of CTLA4 blockade with the fully human mAb CP-675,206 as single-agent therapy in pts with relapsed/ refractory colorectal cancer. Methods: A single-arm, multicenter, phase II trial of CP-675,206 was conducted in pts with measurable adenocarcinoma of the colon or rectum failing standard treatments and with an ECOG performance status of 0 or 1. Patients received 15 mg/kg Q90 days via IV infusion until disease progression. The primary objective was response rate by RECIST criteria. Secondary objectives included safety, duration of response, progression-free survival, and overall survival. Results: A total of 47 pts who received a median of 4 previous therapies (range, 1 to 9) were treated, and 46 experienced disease progression or death because of disease before reaching the planned second dose at 3 months. Grade 3 or 4 adverse events attributed to study drug were limited to diarrhea (n = 3, 6.4%) and idiopathic thrombocytopenia purpura (n = 1, 2.1%). Four pts (8.5%) had grade 2 diarrhea. Four pts received steroids and 2 received infliximab. One patient was removed for toxicity (diarrhea in the setting of what appeared to be treatment-related ulcerative colitis that was responsive to steroids). One patient (2%; 95% CI = 0%, 11%) had a stable ovarian mass and a substantial regression in an adrenal mass. This patient is continuing on study and has received a second dose. Conclusions: In heavily pretreated pts with colorectal cancer and good performance status, CP- 675,206 was tolerable. However, in this setting, CP-675,206 at 15 mg/kg did not demonstrate substantial single-agent activity.

No significant financial relationships to disclose.
Lumiliximab (anti-CD23 antibody) mediates apoptosis and antitumor activity in chronic lymphocytic leukemia (CLL) cells and CD23+ lymphoma cell lines
Authors: Pathan N. , Byrd J. , Hariharan K. , Chu P. , Molina A.
Published: March 2020

3039

Background: Given the success of treating CLL with antibody therapies, interest in those directed at alternative B-cell antigens remains high. Lumiliximab is a chimeric macaque and human anti-CD23 monoclonal antibody whose antigen is expressed on almost all CLL cells. Methods: We examined lumiliximab’s ability to mediate direct apoptosis, antibody-dependent cellular cytotoxicity (ADCC), and complement-dependent cytotoxicity (CDC) against primary CLL cells and CD23+ B-cell lines. Apoptosis was measured with a flow-cytometry based assay for active caspase-3. ADCC was determined by 51Cr-release assay. CDC assays were performed in the presence of 30% autologous plasma from patients and quantified by propidium iodide staining. Western blotting analysis was used to monitor protein expression before and after treatment with lumiliximab. The CD23+ human lymphoma SKW6.4 cell line was used for in vivo evaluation of lumiliximab in a disseminated human lymphoma model. Results: Lumiliximab mediates apoptosis, ADCC, and CDC in CD23+ B-cell lines. However, in primary CLL cells, the primary mechanism of cell killing appears to be mediated via apoptosis. Apoptosis induced by lumiliximab occurs mainly through the intrinsic pathway used by other CLL therapies. Lumiliximab decreased expression of Bcl-2 and XIAP and inhibited Akt activation in CLL cells. Lumiliximab when combined in vitro or in vivo with rituximab or fludarabine effectively mediates synergistic cytotoxicity against primary CLL cells and CD23+ B-cell lines. Significant antitumor activity was also observed with lumiliximab vs a control antibody in a SCID mouse model of human B-cell lymphoma (P <.01). More importantly, lumiliximab + rituximab or lumiliximab + fludarabine results in prolonged survival vs lumiliximab, rituximab, or fludarabine single-agent treatment. Conclusions: These results indicate that lumiliximab induces apoptosis by activating caspases and downregulating antiapoptotic proteins, and suggest that in combination with rituximab or chemotherapy, lumiliximab synergistically enhances antitumor activity in CLL or other B-cell malignancies in which this antigen is overexpressed.

No significant financial relationships to disclose.
Construction and targeting of a 5F11-scFv-methioninase fusion protein for antibody-directed enzyme pro-drug therapy (ADEPT) against neuroblastoma
Authors: Hu J. , Guo H. , Xu H. , Cheung N. V.
Published: March 2020

3043

Background: Recombinant methioninase (METase) depletes methionine and inhibits tumor growth in preclinical models. 5F11 single-chain variable fragment (scFv) can target fusion proteins (e.g. streptavidin (SA), J. Nucl. Med., 45:867, 2004) preferentially to GD2- positive human neuroblastoma (NB). METase targeted to tumors may release methylselenol from the prodrug selenomethionine for tumor therapy. Methods: 5F11-scFv gene fused upstream of METase in pKK-223–3 to form 5F11-scFv-METase. Fusion protein produced in E. coli and purified by chromatography and endotoxin removal retained enzyme activity. Binding of 5F11-scFv-METase to tumor cells was assayed by indirect immunofluorescence and binding kinetics to GD2 analyzed by surface plasmon resonance. Cytotoxicity against human NB cell lines LAN-1, NMB-7 and SK-N-ER was tested using proliferation inhibition and apoptosis assays. Targeting to NB xenografts was studied by biodistribution using 125I-anti-idiotype 1G8 as the secondary tracking antibody. Results: 5F11-scFv-METase was purified to 84% and 94.1% homogeneity by SDS-PAGE and HPLC, respectively. Enzyme activity was 3.6 units/mg protein. Its avidity (KD=1.72×10-7M) as a dimer compared favorably with the monomeric 5F11-scFv (KD=1.07×10- 7M) and tetrameric 5F11-scFv-SA (KD=2.62×10-9M). Immunofluorescent staining of 5F11-scFv-METase was comparable to 5F11-scFv-SA for LAN-1 and NMB-7. In the presence of 20 μM selenomethionine, IC50 of 5F11-scFv-METase was 0.03, 0.02 and 0.02 units/ml for LAN-1, NMB-7 and SK-N-ER, respectively. When treated with 0.3 units/ml of 5F11-scFv-METase and 20 μM selenomethionine, apoptosis was induced in SK-N-ER by 8 hours, peaking at 24 hours. In biodistribution studies, tumor uptake in LAN-1 xenograft averaged 4.07±0.6% injected dose per gram at 48 hours. Conclusions: 5F11-scFv-METase fusion protein retains enzyme activity and immunoreactivity. It targets to tumors in vivo and activates the pro-drug selenomethionine to effect tumor cytotoxicity. Its potential for tumor-selective methionine depletion as well as in ADEPT applications deserves further studies.

No significant financial relationships to disclose.
Effects of the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) on proliferation and cytokine secretion of immune cells in malignant pleural effusion
Authors: Sebastian M. , Jaeger M. , Kiewe P. , Schuette W. , Wiewrodt R. , Lindhofer H. , Mueller B. , Friccius-Quecke H. , Friccius- Quecke H. , Schmittel A.
Published: March 2020

3046

Background: The trifunctional antibody catumaxomab specifically binds EpCAM+ tumor cells, CD3+ T lymphocytes and accessory cells via FcγR I/III. Thus the antibody induces tumor specific cell mediated cytotoxicity in vitro and in vivo. Following last years’ ASCO presentation on a phase I/II trial showing safety and efficacy of repetitive intrapleural administration of catumaxomab in patients with EpCAM positive, malignant pleural effusion (MPE), we now present data on the responsiveness of immune cells from pleural fluid to catumaxomab. Methods: Pleural fluid of patients with EpCAM-positive MPE treated with i.pl. catumaxomab was collected before treatment. Cells were harvested from the fluid and cultured ± 100 ng/ml catumaxomab using an in vitro proliferation assay. After 72 h of culture, proliferation of T cells (CD4+ and CD8+) and monocytes (CD11c+) was determined. In addition, cell supernatants after 24h incubation ± catumaxomab were analysed for their TH1/TH2 cytokine profile (IL-2, IL-4, IL-6, IL-10, IFN-γ and TNF- a). Results: Incubation in presence of catumaxomab led to a pronounced increase of CD4+ CD8+ and CD11+ cell numbers indicating a proliferation of these cells, whereas cultures without catumaxomab showed no proliferation of immune cells. Analysis of supernatants after 24 h revealed levels of IL-2, IL-6, IFN-γ and TNF-a, from cells incubated with catumaxomab that were distinctly higher than in cultures without catumaxomab. Conclusions: The immunologic nature of catumaxomab-induced responses in patients with pleural effusion accompanied by a reduction of tumor cells, could be underlined impressively with in vitro data obtained from pleural cells showing catumaxomab-induced proliferation of T cells and accessory cells and TH1-directed cytokine secretion. The data are equivalent to results observed in the peritoneal fluid of ascites patients.

[Table: see text]
Antibody-secreting cells to deliver antibody against brain metastases
Authors: Lampson L. A. , Tripp C. A.
Published: March 2020

3047

Background: Antibody (AB) therapy has been successful against breast cancer, but brain mets are not well controlled. One likely factor is that AB molecules are too large to cross the blood-brain barrier (BBB). One approach is to truncate the AB, but this can affect its function. We propose an alternative. Unlike inert proteins, cells can cross the BBB. Indeed, antibody-secreting cells (ASC) are found in the brain in many neurologic disorders. Our hypothesis is that ASC, lodged within the brain, can be a source of AB to attack both pre-existing and new brain mets. We describe a new rat model to test this, and initial findings. Methods: Rat mammary carcinoma 13762 was made to constitutively express surrogate tumor antigens, either b-galactosidase (b-gal) or alkaline phosphatase (ap). Tumor cells were injected into the left common carotid artery of syngeneic CDF rats, to favor delivery to the brain. Tumor is identified by staining for keratin or the surrogate antigen. In a new assay, ASC are identified by a histochemical stain for their cognate antigen. As a positive control for ASC staining, spleens of immunized rats are used. Results: 1) The new histochemical assay does identify ASC correctly in positive and negative control spleens. 2) In the brains of rats that had been pre-immunized to b-gal, ASC specific for b-gal were seen at sites of b-gal+ tumor. 3) Some ASC were also seen away from tumor. Conclusions: Although ASC are known to enter the brain in many neurologic disorders, little work has stressed brain metastases. This new model allows study of ASC traffic to the brain in a tumor context. Favored sites of ASC entry and retention can be defined in both tumor-free brains (as appropriate for prophylaxis) and brains with pre-existing metastases.

No significant financial relationships to disclose.
Anti-leukemia activity of CD33-specific chimeric cytotoxic T lymphocytes in vitro and in vivo is impaired by addition of the CD28 costimulatory endodomain
Authors: Dutour A. , Lee D. , Napier S. , Yvon E. , Finney H. , Brenner M. , Rousseau R.
Published: March 2020

3052

Background: EBV-specific cytotoxic T cells (EBV-CTLs) expand and have long-term activity in vivo due to the sustained costimulation provided by the EBV-infected cells produced by this persistent virus. We exploited this phenomenon and redirected EBV-CTLs against CD33, a surface protein expressed on the malignant blasts of acute myeloid leukemia (AML) cells. Methods: EBV-CTLs generated from six EBV-seropositive donors were transduced using a retroviral vector encoding CD33 specific chimeric receptor (cR). We evaluated whether the high and sustained activity shown against native EBV+ target cells can be extended to the CD33+ EBV- targets of the chimeric receptor and whether the addition of CD28 signaling domain improved the receptor activity. Results: cRCD33-EBV-CTL maintained killed EBV-LCL and CD33+ targets (specific lysis respectively of 30% and 35% at E:T ratio 25:1). They produced Th-1, Th-2 and Tc cytokines on exposure to CD33+ targets. Addition of the CD28 intracellular domain did not increase cytotoxicity to CD33+ targets. Preincubation of CD33+ cells with the CD33-blocking MoAb resulted in up to 40% inhibition of lysis and up to 60% inhibition of cytokine release by cRCD33-EBV-CTLs confirming the specificity of the TCR interactions with CD33. NOD-SCID mice bearing a human CD33+ AML were injected with EBV-CTLs ×4 weekly starting 5 days after tumor inoculation. Significant tumor reduction was only observed in mice treated with the cRCD33-EBV-CTLs (p<0.05). Immunohistologic analysis showed the presence of a majority of CD8+ human T cells in the tumors of treated mice. Incorporation of the CD28 endodomain resulted in less tumor-infiltrating T cells in mice treated with cRCD33CD28-EBV-CTLs. There was no significant difference in the chemokines receptor expression on cRCD33CD28-EBV-CTLs but their rate of apoptosis was 16 % higher (p<0.05) than the one of cRCD33-EBV-CTLs. Conclusions: EBV- CTL expressing the CD33 chimeric receptor are functional in vitro and in vivo in mice. CD28 signaling may have a deleterious role for the activity of chimeric receptors in vivo.

No significant financial relationships to disclose.
Depletion of Normal and Malignant B cells with a CD37-specific SMIP molecule
Authors: Cerveny C. , Grosmaire L. , Espling E. , Bader R. , Nilsson C. , Baum P. , Wahl A. , Ledbetter J. , Hayden-Ledbetter M.
Published: March 2020

3063

Background: CD37 is a member of the tetraspanin family expressed at high levels by normal mature B cells and by most B cell malignancies. Previously, an antibody to CD37 has been labeled with 131I and tested in clinical trials for therapy of NHL. Treatment with 131I-MB-1, resulted in durable tumor remissions in patients lasting from 4 to 11 months (Press OW, Eary JF, Badger CC, et al. Treatment of refractory non-Hodgkin’s lymphoma with radiolabeled MB-1 (anti-CD37) antibody. J Clin Oncol. 1989;7:1027–1038). Here we assess the functional properties and therapeutic potential of a small modular immunopharmaceutical (SMIP) targeting CD37. Methods: Growth arrest and apoptosis of B lymphoma cell lines was assessed. ADCC activity was evaluated using BJAB targets and human peripheral blood mononuclear cells (PBMC) effectors. Drug-drug interactions were assessed by the Combination Index method. In vivo studies were performed utilizing established human B cell tumor xenografts in nude mice. Results: A CD37-directed SMIP drug candidate mediated growth arrest, apoptosis and ADCC, but not CDC, towards B lymphoma cell lines. The protein showed significant anti-tumor activity in a mouse xenograft model, and selectively depleted normal human B cells in short term cultures of PBMC. When combined with rituximab, the molecule increased apoptosis, C1q binding, and C’ dependent target cell death in vitro, and increased anti-tumor activity in vivo in a xenograft model. Conclusions: In vitro and in vivo characterization of the CD37-targeted SMIP drug suggest a potent capacity to eliminate target cells through combined effects of direct target cell signaling and effector cell recruitment. CD37-mediated growth was synergistic with standard chemotherapies in vitro and showed additive in vivo activity with CD20-targeted therapy. On the basis of these data CD37-directed SMIP therapy is being developed for clinical evaluation against B cell malignancies.

No significant financial relationships to disclose.
Five-year overall survival (OS) in non-metastatic androgen-independent prostate cancer (AIPC) patients (pts) treated with nilutamide (N), vaccine (V), and combination therapy
Authors: Madan R. A. , Gulley J. L. , Dahut W. L. , Steinberg S. M. , Liewehr D. J. , Schlom J. , Arlen P. M.
Published: March 2020

3066

Introduction: There is no standard treatment for pts with non-metastatic AIPC (D0.5).We previously performed the first randomized study in this pt population involving N,V, and combination therapy. To our knowledge this report is the first prospective analysis of OS data in pts with stage D0.5 AIPC. Methods: The initial study randomized 21 pts to treatment with N and 21 pts to treatment with V. The V was an admixture containing a vaccinia vector with the gene for PSA combined with vaccinia containing the costimulatory molecule B7.1. As part of this V strategy, pts also received monthly boosts of fowlpox-PSA with GM-CSF and IL-2 with all vaccinations. Pts who developed rising serum PSA levels on either arm could cross-over to receive both V and N. Initial data demonstrated a clinical benefit in pts treated with combination V and N. Pts characteristics were reviewed and OS was determined using the social security death index. Actuarial analyses of the data using the Kaplan-Meier method were performed. Results: The OS from on-study date in all randomized pts was 4.6 years (yrs) with 3yr OS=71% and 5yr OS=48%. There was no difference in OS in all pts based on Gleason Score (GS) or PSA at diagnosis (dx), orchiectomy, radical prostatectomy, or radiation therapy. However, a subgroup analysis showed a trend to improved OS for pts treated with V alone or V+N (compared to N alone or N+V), who had GS <7 (p=0.18), PSA<20 (p=0.077), and PSA doubling time<3 months (p=0.14). Comparing OS in the study arms: Conclusion: Although these results were not statistically significant due to small cohort sizes, there was a clear trend in both 3yr and 5yr OS in the pts who received V first and crossed-over to V+N, as compared with the reciprocal scheduling of N followed by N+V. A randomized trial at the NCI will compare androgen deprivation therapy (ADT) alone vs ADT plus vaccine to further study the benefits of combination therapy in this population.

[Table: see text]

No significant financial relationships to disclose.
A phase Ib/II study of PXD101 alone and in combination with 5-fluorouracil in patients with advanced solid tumors
Authors: Northfelt D. W. , Marschke R. F. , Bonnem E. , Ooi C. E. , Gerwien R. , Hawthorne T. , Clarke A. , Buhl-Jensen P. , Von Hoff D. , Grem J.
Published: March 2020

3501

Background: PXD101 is a hydroxamate HDAC inhibitor that has broad anti-neoplastic activity in vivo and in vitro. Preclinical data showing PXD101 down-regulation of thymidylate synthase (TS), an in vivo target of 5-fluorouracil (5-FU) provide a rationale for combination of PXD101 with 5-FU. Methods: This is a phase Ib/II trial of PXD101 plus 5-FU in patients with advanced solid tumors, with dose escalation to establish the maximum tolerated dose (MTD) and an expansion at the MTD in colorectal cancer (CRC) patients. Patients (pts) must be = 18 yrs, have measurable disease, and had disease progression after standard chemotherapy. PXD101 was administered as a 30-min IV infusion on Days 1–5 of a 3-wk cycle. 5-FU was administered from cycle 2 on, as a continuous 96-hr IV infusion starting on Day 2 of the same 3-wk cycle. The primary endpoints were safety, and effect of belinostat on TS expression in patients’ tumors. Dose-limiting toxicities (DLTs) were PXD101-related = Gr 3 non-hematologic or Gr 4 hematologic toxicities. Expression of TS mRNA was measured by RTQ-PCR. Results: Twenty pts have been treated for a median of 2 cycles (range 1–8). Cohorts of 3–6 pts were tested at 5 dose levels of PXD101/5-FU (mg/m2/d): 300/250, 600/250, 1,000/250, 1,000/500, and 1,000/1,000. Two pts did not complete cycle 2, and one pt at the 600/250 dose level received 1,000 mg/m2/d 5-FU. There were no DLTs in the first 4 dose cohorts; the 5th cohort is ongoing. In the first 4 dose cohorts (17 pts), the most frequent AEs were fatigue, nausea/vomiting, dysgeusia, dehydration, constipation, edema, anorexia and anemia. There were 2 Gr 4 AEs (pulmonary embolism, bacteremia); Gr 3 AEs in = 2 pts were fatigue and dehydration. All Gr 3/4 events were assessed as not related to PXD101. One pt with stage IV CRC treated at 600/1,000 mg/m2/d PXD101/5-FU had stable disease (SD) for 8 cycles, and one pt with stage IV esophageal cancer treated at the 1,000/250 mg/m2/d dose had SD for 4 cycles. Conclusions: PXD101 in combination with 5-FU has been well tolerated up to 1,000/500 mg/m2/d PXD101/5-FU. The study is ongoing and data from the MTD expansion part, including effect of PXD101 on tumor TS expression, will be presented.

No significant financial relationships to disclose.
Paclitaxel enhances antibody-dependent cell-mediated cytotoxicity of trastuzumab by a rapid recruitment of natural killer cells in Her-2 overexpressing breast cancer
Authors: Miura D. , Yoneyama K. , Furuhata Y. , Kawabata H.
Published: March 2020

3503

Background: One of the important mechanisms that trastuzumab (TZ) inhibits the growth of Her-2 overexpressing breast cancer cells is the activation of a host tumor response via antibody-dependent cell-mediated cytotoxicity (ADCC). Although paclitaxel (PTX) has a synergistic effect in combination with TZ, whether the ADCC is enhanced by PTX is less known. We questioned whether adding PTX to TZ enhances ADCC and also investigated kinetics of effector cells in ADCC. Methods: Twenty-eight patients with Her-2 overexpression, 9 received the combination of (4mg/kg as a loading and 2 mg/kg weekly) and PTX (80 mg/m2 weekly) and 19 did monotherapy of TZ, were studied. Using blood samples (mononuclear cells) taken before and 10 minutes after administrations, ADCC and the number of effector cells including NK cell, monocyte, and CD64+ cell were compared in each case (after/before). ADCC was analyzed by 51Cr releasing assay using SK-BR-3 cell line and the fractions of NK cells (both CD16+(FcγRIII) and CD56+) and CD64+(FcγRI) cells were analyzed by flow cytometry. Results: ADCC levels increased in + 9% (mean) after TZ monotherapy and + 120% (p<0.05) after the combination of TZ and PTX. All 9 patients in combination had enhancements in ADCC levels. As regards effector cells, NK cells increased in + 51% after TZ alone and in + 112% (p<0.05) after the combination. No significant changes were found in monocytes (+ 39%) and CD64+ cells (+ 53%) after TZ, however monocytes decreased in - 40% (p<0.05) and also CD64+ in - 24% after the combination. Conclusions: Adding PTX to TZ significantly enhanced ADCC, which level was twice as strong as TZ monotherapy, by a rapid recruitment of NK cells. This may reflect that a combination of TZ and PTX has a strong synergistic effect than we expected in Her- 2 overexpressing breast cancer.

No significant financial relationships to disclose.
Characterization of 89Zr-trastuzumab for clinical HER2 immunoPET imaging
Authors: Dijkers E. , Lub-de Hooge M. N. , Kosterink J. G. , Jager P. L. , Brouwers A. H. , Perk L. R. , van Dongen G. A. , de Vries E. G.
Published: March 2020

3508

Background: SPECT imaging with 111In-DTPA-trastuzumab has recently identified new tumor lesions, undetected with conventional staging, in 13/15 patients with HER2++ breast cancers (Perik et al., J Clin Oncol 2006). The aim of this study was to develop an immunoPET label, suitable for clinical use, which would allow excellent detection of HER2 positive tumor lesions and quantification of HER2 expression levels in vivo. Methods: Trastuzumab has essentially been radiolabeled as described by Verel et al. (J Nucl Med 2003). Radiochemical purity (rcp) and stability were determined by SEC-HPLC, immunoreactivity with a Lindmo assay. Biodistribution was performed in nude mice bearing HER2 positive (SKOV3) or HER2 negative (GLC4) xenografts. Five animals per group were co-injected with 111In-ITC-DTPA-trastuzumab and 89Zr-trastuzumab, imaged on a microPET (Focus 220) and sacrificed 144 hours post injection. Results: The immunoreactive fraction of 89Zr-trastuzumab was 0.96, labeling efficiency > 90% and rcp > 95%. 89Zr-trastuzumab was stable for 7 days in buffer at 4 °C and in human serum at 37 °C. MicroPET imaging showed excellent tumor uptake and could easily detect metastases with a size approximating the spatial resolution of the microPET scanner. 89Zr- and 111In-ITC-DTPA-trastuzumab showed similar biodistribution. Highest uptake was found in HER2 positive tumors at 144 hours post injection (40% ID/g tissue for 89Zr-trastuzumab and 47% ID/g for 111In-ITC-DTPA-trastuzumab) compared to 8% ID/g tissue in HER2 negative control tumors. Liver uptake was low (8–12% ID/g tissue). Preliminary results in HER2 positive breast cancer patients show excellent tumor tracer uptake and a resolution unapproachable by 111In-DTPA-trastuzumab. Conclusions: 89Zr-trastuzumab is stable, shows excellent and specific tumor uptake and is suitable for clinical use. Minimal aspecific tracer uptake in the liver allows detection of abdominal metastases.

No significant financial relationships to disclose.