A Phase I Study of Apolizumab, an Anti-HLA-DR ß-chain Monoclonal Antibody, in Patients With Solid Tumor Malignancies.

BACKGROUND: Human leukocyte antigen (HLA)-DR, a member of the major histocompatibility complex class II antigen family, is a target for antibody-based therapeutics. Apolizumab (Hu1D10, Remitogen), a humanized IgG1 monoclonal anti-HLA-DR ß-chain antibody targets the antigen, 1D10, expressed on a wide variety of hematologic and solid tumor malignancies. In this Phase 1 trial, the maximum tolerated dose and dose-limiting toxicity of weekly apolizumab in patients with advanced solid tumor malignancies were determined. PATIENTS AND METHODS: Eligible patients with refractory solid tumors were initially screened for ID10 Ag on their tumor. Patients whose tumors expressed 1D10 were administered apolizumab 0.5, 1.0, 1.5, or 3.0 mg/kg intravenously over 90 minutes weekly for 4 consecutive weeks, followed by a 4-week break, and assessment of response. Patients whose disease had not progressed were offered additional treatment. RESULTS: Tumors from 75 patients were screened for 1D10 Ag of which 17 patients were positive and underwent treatment. The first 3 dose levels were well-tolerated. Dose-limiting toxicities of grade 3 infusion-related hypersensitivity reactions and grade 3 headache and hypertension occurred in 2 patients, respectively, at apolizumab 3.0 mg/kg. Four patients, 1 each with breast carcinoma, melanoma, renal cell carcinoma, and sarcoma had stable disease for a median of 15 weeks (range: 12 to 19 wk). CONCLUSION: Apolizumab can be administered safely at a maximum tolerated dose of 1.5 mg/kg for 4 consecutive weeks. Adverse events and limited clinical data in both hematologic and solid tumor malignancies resulted in discontinuation of clinical development of apolizumab. HLA-DR remains an interesting immunotherapeutic target.

First-Line Aldoxorubicin vs Doxorubicin in Metastatic or Locally Advanced Unresectable Soft-Tissue Sarcoma: A Phase 2b Randomized Clinical Trial.

IMPORTANCE: Standard therapy for advanced soft-tissue sarcoma has not changed substantially in decades, and patient prognosis remains poor. Aldoxorubicin, a novel albumin-binding prodrug of doxorubicin, showed clinical activity against advanced soft-tissue sarcoma in phase 1 studies. OBJECTIVE: To evaluate efficacy and safety of aldoxorubicin vs doxorubicin in patients with advanced soft-tissue sarcoma. DESIGN, SETTING, AND PARTICIPANTS: International, multicenter, phase 2b, open-label, randomized study at general community practices, private practices, or institutional practices. Between August 2012 and December 2013, 140 patients with previously untreated locally advanced, unresectable, or metastatic soft-tissue sarcoma were screened. INTERVENTIONS: Randomization (2:1) to aldoxorubicin 350 mg/m2 (dose equivalent to doxorubicin 260 mg/m2) or doxorubicin 75 mg/m2, administered once every 3 weeks for up to 6 cycles. MAIN OUTCOMES AND MEASURES: Primary end point was progression-free survival. Secondary end points were 6-month progression-free survival, overall survival, tumor response rate, and safety. All efficacy end points were evaluated by independent and local review. RESULTS: A total of 126 patients were randomized, and 123 received aldoxorubicin (n = 83) or doxorubicin (n = 40). Median (range) patient age was 54.0 (21-77 years); 42 (34%) had leiomyosarcoma. By independent review, median progression-free survival was significantly improved (5.6 [95% CI, 3.0-8.1] vs 2.7 [95% CI, 1.6-4.3] months; P = .02) with aldoxorubicin compared with doxorubicin, as was the rate of 6-month progression-free survival (46% and 23%; P = .02). Median overall survival was 15.8 (95% CI, 13.0 to not available) months with aldoxorubicin and 14.3 (95% CI, 8.6-20.6) months with doxorubicin (P = .21). Overall tumor response rate (by Response Evaluation Criteria in Solid Tumors, version 1.1) by independent review was higher with aldoxorubicin than with doxorubicin (25% [20 patients, all partial response] vs 0%). Grade 3 or 4 neutropenia was more frequent with aldoxorubicin than with doxorubicin (24 [29%] vs 5 [12%]), but not grade 3 or 4 febrile neutropenia (12 [14%] vs 7 [18%]). No acute cardiotoxic effects were observed with either treatment, although left ventricular ejection fraction less than 50% occurred in 3 of 40 patients receiving doxorubicin. CONCLUSIONS AND RELEVANCE: Single-agent aldoxorubicin therapy showed superior efficacy over doxorubicin by prolonging progression-free survival and improving rates of 6-month progression-free survival and tumor response. Aldoxorubicin therapy exhibited manageable adverse effects, without unexpected events, and without evidence of acute cardiotoxicity. Further investigation of aldoxorubicin therapy in advanced soft-tissue sarcoma is warranted. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01514188.

Pharmacokinetic study of aldoxorubicin in patients with solid tumors.

Introduction Aldoxorubicin, a prodrug of doxorubicin, binds covalently to serum albumin in the bloodstream and accumulates in tumors. Aldoxorubicin can be administered at doses several-fold higher than doxorubicin can, without associated acute cardiotoxicity. Purpose This study fully evaluated the pharmacokinetic profile of aldoxorubicin (serum and urine). Methods Eighteen patients with advanced solid tumors received aldoxorubicin 230 or 350 mg/m(2) (equivalent in drug load to doxorubicin at doses of 170 or 260 mg/m(2), respectively) once every 21 days. Blood samples were taken in cycle 1 before aldoxorubicin infusion, and at 5, 15, 30, and 60 min, and at 2, 4, 8, 12, 16, 24, 48, and 72 h after infusion. Urine samples were taken in cycle 1 at 24, 48, and 72 h after infusion. Limited blood sampling was done in cycle 3, before aldoxorubicin infusion, and at 60 min and at 2, 4, and 8 h after infusion. Results The long mean half-life (20.1-21.1 h), narrow mean volume of distribution (3.96-4.08 L/m(2)), and slow mean clearance rate (0.136-0.152 L/h/m(2)) suggest that aldoxorubicin is stable in circulation and does not accumulate readily in body compartments outside of the bloodstream. Very little doxorubicin and its major metabolite doxorubicinol, which has been implicated in doxorubicin-associated cardiotoxicity, are excreted in urine. This might explain the lack of cardiotoxicity observed thus far with aldoxorubicin. Conclusions Our findings support dosing and administration schemas used in an ongoing phase 3 clinical study of aldoxorubicin in soft tissue sarcoma, and phase 2 clinical studies in small cell lung cancer, glioblastoma, and Kaposi's sarcoma.

A phase 1B/2 study of aldoxorubicin in patients with soft tissue sarcoma.

BACKGROUND: Aldoxorubicin, a prodrug of doxorubicin, covalently binds to serum albumin, allowing for the administration of much higher doses of doxorubicin in a previous clinical study. The current phase 1B/2 study evaluated the safety of aldoxorubicin, including preliminary efficacy and safety of its maximum tolerated dose (MTD). METHODS: Patients aged 18 to 70 years with recurrent/refractory malignant solid tumors received aldoxorubicin at a dose of 230 mg/m(2) , 350 mg/m(2) , or 450 mg/m(2) (170 mg/m(2) , 260 mg/m(2) , or 335 mg/m(2) doxorubicin equivalents, respectively) by intravenous infusion once every 21 days for up to 8 consecutive cycles. RESULTS: A total of 25 patients were enrolled, including 17 patients (68%) with advanced soft tissue sarcoma (STS). The MTD of aldoxorubicin was 350 mg/m(2) ; dose-limiting toxicities included grade 4 neutropenia and grade 3 febrile neutropenia (NCI CTCAE v4.0). Drug-related adverse events included myelosuppression, nausea, fatigue, alopecia, stomatitis, vomiting, and oropharyngeal pain. No clinically significant cardiac toxicities were reported. Seven patients (28%) had elevated serum troponin levels while taking part in the study, but these elevations were not clinically significant or associated with cardiac findings. A partial response was achieved in 20% of patients, and stable disease was reported in 40% of patients. The median progression-free survival was 4.80 months, and the median overall survival was 11.25 months. Among patients with STS who were treated at the MTD (13 patients), a partial response was achieved in 38% and stable disease in 46%; the median progression-free survival was 11.25 months and the median overall survival was 21.71 months. CONCLUSIONS: Aldoxorubicin at a dose of 350 mg/m(2) administered once every 21 days for up to 8 cycles was found to be acceptably safe and demonstrated preliminary efficacy in patients with advanced solid tumors, including STS. Further investigation of aldoxorubicin is ongoing.

In vivo pharmacodynamic effects of Hu1D10 (remitogen), a humanized antibody reactive against a polymorphic determinant of HLA-DR expressed on B cells.

The humanized monoclonal antibody Hu1D10 (Remitogen, Protein Design Labs, Fremont, CA) recognizes a polymorphic determinant of human leukocyte antigen-DR expressed on the majority of B-cell lymphomas and on normal B cells of most individuals. Hu1D10 mediates complement-mediated cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and apoptosis of 1D10 antigen (Ag)-positive B cells in vitro. The 1D10 Ag is expressed on a variety of tissues but is restricted primarily to lymphocytes, macrophages, and mesenchymal dendritic cells. The safety and pharmacology of Hu1D10 were investigated in rhesus macaques. Animals were prescreened for 1D10 Ag expression on circulating B cells. Sixteen animals received either placebo (4 Ag+ animals), 1 mg/kg Hu1D10 (4 Ag+ animals), or 10 mg/kg Hu1D10 (4 Ag+ animals and 4 Ag- animals) daily via intravenous (i.v.) bolus-injection for 5 consecutive days, and 4 Ag+ animals received 10 mg/kg Hu1D10 via 90 min i.v. infusion x 5 days. Bolus-injection of Hu1D10 resulted in type 1 hypersensitivity reactions in the majority of Ag+ animals and one death due to anaphylaxis. Slow infusion of Hu1D10 was associated with only mild hypersensitivity reactions after the first dose but not subsequent doses. In animals treated with 10 mg/kg Hu1D10 via bolus-injection, the median terminal elimination half-life of Hu1D10 was 2.6 and 8.4 days in Ag+ and Ag- animals, respectively. Administration of Hu1D10 to Ag+ animals resulted in rapid and profound depletion of circulating B cells for 7-10 days following the last dose. No B-cell depletion was observed in Ag- animals, despite slower elimination of Hu1D10. These studies demonstrate that Hu1D10 reacts with antigen-presenting cells in rhesus macaques. It can be safely administered as a slow i.v. infusion but causes severe toxicity when given as a bolus. This study provides the foundation for testing Hu1D10 for the treatment of B-cell malignancies in humans.