Variable-density flow in heterogeneous porous media--laboratory experiments and numerical simulations

Konz, M., Ackerer, P., Younes, A., Huggenberger, P., Zechner, E., 2009a. 2D Stable Layered Laboratory-scale Experiments for Testing Density-coupled Flow Models. Water Resources Research, 45. doi:10.1029/2008WR007118., a series of laboratory-scale 2D tank experiments were conducted and accurately simulated for density driven flow problems on homogeneous porous media. In the present work, we extended the numerical and experimental studies to heterogeneous problems. The heterogeneous porous medium was constructed with a low permeability zone in the centre of the tank and had well-defined parameters and boundary conditions. Concentration distributions were measured in high resolution using a photometric method and an image analysis technique. The numerical model used for the simulations was based on efficient advanced approximations for both spatial and temporal discretizations. The Method Of Lines (MOL) was used to allow higher-order temporal discretization. Three different boundary conditions, corresponding to different localizations of the inflow and the outflow openings at the opposite edges of the tank, were applied to investigate different flow scenarios in the heterogeneous porous medium flow tank. Simulation results of all three density coupled experiments revealed a density-dependent behavior of dispersion. Thus, a reduction of dispersivites was required to obtain a good matching of the experimental data. The high quality of the experiments enabled a detailed testing of numerical variable-density flow codes under heterogeneous conditions. Therefore, the experiments were considered to be reliable benchmark tests.

A medical decision tree for the prophylaxis (P) and treatment (T) of tumor lysis syndrome (TLS): An international TLS consensus panel

e17575

Background: We (MC) previously established a definition of laboratory (LTLS) and clinical TLS (CTLS) and associated grading system (Cairo et al, BJH. 2004). Additionally, we recently reported an evidence based review of guidelines for the P and T of TLS (Coiffier et al, J Clin Oncol. 2008). Rasburicase (R), a recombinant urate oxidase, results in a more rapid and total reduction of uric acid (UA) compared to allopurinol (A) in children at high-risk of TLS (Goldman/Cairo et al, Blood. 2001) and a rapid reduction in UA in adults at high-risk of TLS (Coiffier et al, J Clin Oncol. 2003). It still remains to be determined which patients at risk of developing TLS should receive R versus A as initial TLS prophylaxis. Methods: We convened an international panel (N = 17) of experts in pediatric and adult hematological malignancies and solid tumors (ST) to develop a medical decision tree for the P and T of TLS based on the risk classification (low, medium, high) and management recommendations of Coiffier et al (J Clin Oncol. 2008) Results: Patients without evidence of LTLS were assigned to either low-risk disease (LRD), medium-risk (MRD), or high-risk (HRD). Risk factors included pathological classification stage, bulk, disease burden (WBC/LDH) and renal impairment/involvement. HRD was assigned to patients with either B-ALL, ALL/AML ≥100K/mm3, BL/LL stage III/IV, and/or high LDH, DLBCL/PTCL/MCL/ATL with bulky and elevated LDH and patients with MRD with renal impairment/involvement. MRD consisted of ALL ≤100K/mm3, AML 25–100K/mm3, BL/LL stage I/II and low LDH, childhood ALCL, DLBCL/PTCL/MCL/ATL non-bulky but elevated LDH, CLL treated with targeted therapy, and LRD with renal impairment/involvement. LRD consisted of ST (except bulky sensitive to cytotoxic therapy [MRD]), CML, MM, HL, other NHL and AML <25K/mm3. Conclusions: This medical decision tree will facilitate the practice of management of the P and T of TLS and hopefully improve the quality of care in a cost effective manner. *all authors have equal authorship and contribution

[Table: see text]

First-in-human phase I study of the novel structure proteasome inhibitor NPI-0052

3516

Background: NPI-0052 is a second-generation proteasome inhibitor that has a novel structure with preclinical studies suggesting unique proteasome inhibition (PI), signal transduction, efficacy and toxicology profiles, and activities in a broad range of models including bortezomib (BZ) resistant models. Methods: Patients were treated with NPI-0052 IV weekly x 3 in 4-week cycles in a 3+3 design dose escalation to a Recommended Phase 2 Dose (RP2D). PI was assayed in whole blood (PWB) and in PBMCs. Up to 10 patients each (lymphoma and solid tumors) are treated at the RP2D. Results: 39 patients have been treated between 0.0125 mg/m2 to 0.8 mg/m2 for up to 12 cycles. The RP2D was 0.8 mg/m2 and has been well tolerated in this study, with the most notable drug-related adverse events being N/V, fatigue, diarrhea, dizziness, headache, decreases in hemoglobin, and insomnia. Thrombocytopenia or neuropathy did not appear to be induced by NPI-0052. Escalation was halted at 0.8 mg/m2, as DLT of transient “hallucinations” (visual imprints when eyes closed) and dizziness/unsteady gait were reported in another study at 0.9 mg/m2. PK data indicate T1/2 ∼4–10 minutes, with clearance at 3–15 L/min and Vz of 35–85L. PI (chymotrypsin-like activity) in PWB and PBMC were dose dependent (mean D1 and D15 PI in PWB at 0.8 mg/m2 was 75 and 100%) (efficacious doses of BZ have been reported to result in a range of ∼40–70% PI). PI in PBMC returned to ∼baseline within one week of each dose, while inhibition remained in PWB. Stable disease was observed in patients with cervical carcinoma (11 months; maximum response was 24%; PI increased with dose escalation), colorectal, hepatocellular, adenoid cystic, melanoma, granulosis cell and ovarian. Conclusions: NPI-0052 produces dose-dependent pharmacologic effects, with equal to greater PI seen than reported with therapeutic doses of BZ. At the RP2D toxicity is mild-to-moderate, without the toxicity profile associated with BZ. Together with preclinical data this suggests NPI-0052 may have utility in treating patients who are not candidates for BZ as well as in indications and combinations that have not supported BZ use. Additional trials have been initiated including combinations with other targeted agents.

[Table: see text]

Phase I study of an anti-CD30 Fc engineered humanized monoclonal antibody in Hodgkin lymphoma (HL) or anaplastic large cell lymphoma (ALCL) patients: Safety, pharmacokinetics (PK), immunogenicity, and efficacy

8531

Background: XmAb2513 is a novel 2nd-generation humanized monoclonal antibody (mAb) directed against CD30 (a cell surface antigen expressed on Reed-Sternberg cells of HL and ALCL), with an Fc region engineered to have increased binding affinity to Fcγ receptors (FcγRs) leading to improved FcγR-dependent effector cell functions. In vitro, XmAb2513 was more potent and more efficacious than 1st-generation anti-CD30 mAbs (e.g., SGN-30 & MDX-060). In cynomolgus monkeys (cynos), XmAb2513 exposure was dose-proportional with half-lives ranging from 12 - 17d in repeat dose studies, which suggested biweekly (QOW) dosing in man. A Phase 1 study has been initiated to examine the safety and efficacy of XmAb2513 in patients (pts) with relapsed HL and ALCL. Methods: Phase 1 open-label study with QOW dosing of XmAb2513; dose-escalation study design with doses of 0.3, 1, 3, 6, 9, and 12 mg/kg via IV-infusion to establish the maximum tolerated dose (MTD). Pts receive up to 4 cycles (8 infusions) with sample collections at regular intervals for safety, PK, soluble CD30 (sCD30) and detection of immunogenicity [i.e., human Abs to humanized Abs (HAHA)]. Tumor response is assessed every 2 cycles. Results: 13 HL pts have been enrolled in the 1st 4 dose levels (0.3 to 6 mg/kg). XmAb2513 has been well tolerated. The MTD has not been achieved. 1 pt with an extensive treatment history and chronic immunosuppression died due to fungal pneumonia after a single 3 mg/kg dose. The event was considered unrelated to XmAb2513. PK parameters were computed for the 1st dose alone and for the entire course of XmAb2513 treatment. PK parameters appeared non-linear across the dose range from 0.3 - 3 mg/kg. Half-life appeared to increase after multiple infusions and ranged from 5.3 - 30.2 days in the 1 and 3 mg/kg cohorts. Immunogenicity (HAHA) results have been negative. Tumor reduction has been observed in 1 pt in the 1 mg/kg cohort and 2 in the 3 mg/kg cohort. Conclusions: The MTD of XmAb2513 has not yet been reached due to its tolerability and lack of immunogenicity. PK results are on track with simulations based on PK results from cynos. XmAb2513 has demonstrated encouraging biologic activity in patients with refractory HL.

[Table: see text]

A phase II study of a novel oral isotype-selective histone deacetylase (HDAC) inhibitor in patients with relapsed or refractory Hodgkin lymphoma

8000

Background: MGCD0103 is a non-hydroxamate, isotype-selective, inhibitor of human HDACs. Abnormal regulation of HDAC activity is associated with malignant disease in humans, and small molecule HDAC inhibitors are a novel drug class with anticancer potential. Their proposed anti-Hodgkin activity is through regulation of aberrant gene expression at the transcriptional level by inhibiting proliferation, inducing apoptosis, and/or initiating differentiation in cancer cells. Methods: A phase II trial of MGCD0103 (110 mg 3x/week in 4- week cycles) is ongoing in patients (pts) with relapsed/refractory Hodgkin Lymphoma (RRHL). The primary endpoint is a composite of objective response and stable disease. Results: As of Dec 15th, 2006, 18 pts out of a planned 12–35 have been enrolled; median age 28 (range: 21–62). All pts were previously treated with autologous and/or allogeneic stem cell transplant. The median number of cycles received to date is 2 (range: 1–4). Seven pts have completed =8 weeks (2 cycles) of therapy and are evaluable for response analysis; 5 of these had tumor reduction ranging between 21% and 70% by CT, which is associated with a significant reduction in FDG-PET activity in 4 pts. Of the 18 pts, 5 have had dose reductions/discontinuations due to: mucositis (n=1); fatigue/nausea/diarrhea (n=1); nausea/vomiting (n=1); fatigue (n=1) and pancreatitis/hypotension (n=1). Significant HDAC inhibition (>20% of total activity), was seen in PBMCs from 7/9 pts with samples. Treatment is ongoing in 14 pts; including those with tumor reduction. Criteria have been met to expand to the second stage of the study (>1 response demonstrated in the first 12 patients). Conclusions: Preliminary results suggest that single-agent MGCD0103 demonstrates significant anti-tumor activity in RRHL and is well tolerated at a Phase II dose of 110mg in this ongoing trial.

No significant financial relationships to disclose.

Risk assessment and medical decision model for prophylaxis and treatment of hyperuricemia and tumor lysis syndrome (TLS): International expert panel analysis

17006

Background: Hyperuricemia, a major component of TLS, has historically been prevented and treated using allopurinol and alkalinization, and recently managed effectively by rasburicase (recombinant urate oxidase) in children and adults at high risk of TLS. We sought to determine the risk factors associated with TLS and develop a risk adapted medical decision model for the prevention and treatment of hyperuricemia in TLS. Methods: TLS risk scoring was performed by an expert panel, based on an odds ratio evaluation of 68 patient characteristics and cancers with known TLS risk. The RAND Appropriateness Method (RAM) (1–3 inappropriate, 4–6 uncertain, 7–9 appropriate) was utilized to investigate the appropriateness of prevention and treatment in 92 different scenarios. All appropriateness ratios were validated using a set of 36 clinical cases. The strategies analyzed included no therapy, hydration (± diuretics [DI]), rasburicase, allopurinol, and allopurinol + alkalinization. Results: Risk factors (±SD) identified included age ≥ 60 years (1.6±0.5), decreased renal function (2.7±1.1), renal tumor infiltration (1.5±0.3), initial cytoreductive therapy (2.5±1.2), acute lymphoblastic leukemia with WBC ≥50x109/L [Burkitt 8.6±5.3; pre-B 4.3±2.4; T-cell 4.6±2.8]; and non-Hodgkin lymphoma with LDH≥ 2x normal [Burkitt 6.6±3.0; lymphoblastic 3.2±2.8; diffuse large B-cell 2.4±1.9]. Hydration (± DI) was considered appropriate while no treatment and allopurinol + alkalinization were inappropriate in all scenarios. For prophylaxis, rasburicase was more appropriate than allopurinol (8.5±0.5 vs 4.9±2.1; p<0.025) in patients with hyperuricemia and/or at high risk of TLS, whereas allopurinol was more appropriate than rasburicase (6.2±1.0 vs 4.9±1.9; p<0.05) in those at low or moderate risk. In patients with TLS and normal urine output and uric acid, allopurinol and rasburicase were considered equally appropriate (5.0±0.9 vs 5.8±0.3). Conclusions: In summary, in addition to hydration (± DI), rasburicase is appropriate for patients at high risk of TLS and/or with hyperuricemia, and allopurinol for those with low risk of TLS and/or normal uric acid concentration.

[Table: see text]

A phase I/II study of galiximab (an anti-CD80 monoclonal antibody) in combination with rituximab for relapsed or refractory, follicular lymphoma

BACKGROUND

Galiximab is a monoclonal antibody that targets CD80, a costimulatory molecule constitutively expressed on follicular and other lymphomas. Modest single-agent clinical activity and tolerability were demonstrated in a phase I study in relapsed or refractory, follicular non-Hodgkin's lymphoma (NHL). A phase I/II study was conducted to evaluate galiximab in combination with a standard course of rituximab. Safety, pharmacokinetics, and efficacy were evaluated.

PATIENTS AND METHODS

Patients with follicular NHL who had relapsed or failed primary therapy were enrolled. Rituximab-refractory patients (no response or a response with time to progression <6 months) were excluded. Patients received 4 weekly i.v. infusions of galiximab (125, 250, 375, or 500 mg/m(2)) and rituximab (375 mg/m(2)). International Workshop Response Criteria (IWRC) were used to evaluate response.

RESULTS

Seventy-three patients received treatment. All had received at least one prior lymphoma therapy; 40% were rituximab naive. Infusions were delivered in an outpatient setting and were well tolerated. The most common study-related adverse events (AE) were lymphopenia, leukopenia, neutropenia, fatigue, and chills. The overall response rate at the recommended phase II dose of galiximab (500 mg/m(2)) was 66%: 19% complete response, 14% unconfirmed complete response, and 33% partial response. The median progression free survival was 12.1 months. Combination therapy did not appear to alter pharmacokinetics.

CONCLUSION

These results indicate that galiximab can be safely combined with a standard course of rituximab. This doublet biologic approach offers the potential to avoid or delay chemotherapy or to integrate with other lymphoma therapies. A phase III, randomized study evaluating clinical benefit of rituximab versus the combination has been initiated.

Preclinical rationale for therapeutic targeting of mTOR by CC-I779 and rapamycin in Hodgkin lymphoma

10070

Background: Although conventional chemotherapy has been the golden standard for the treatment of Hodgkin Lymphoma (HL), significant long-term toxicities necessitate the need for development of targeted therapy that is potentially less toxic to normal cells. We and others have recently reported that the PI3K/AKT pathway is aberrantly activated in primary and cultured HL cells, and its inhibition induces apoptosis and cell cycle arrest. Because only mTOR inhibitors are currently being evaluated in clinical trials, we examined the biologic and molecular activity of two mTOR inhibitors CCI-779 and rapamycin in HL cell lines, and determined the molecular mechanisms of their activity. Methods: Three HL-derived cell lines were used (HD-LM2, L-428, and KM-H2). Cell viability was determined by the MTS assay. Cell cycle arrest was determined by propidium iodide staining and FACS analysis. Autophagy was determined by staining of intracellular organelles with Acridine Orange and FACS analysis. Molecular changes were determined by western blot. Results: The antiproliferative effect of CCI-779 and rapamycin in all HL cell lines was evident as early as 24 hour and was time- and dose-dependent. CCI-779 induced cell cycle arrest in all cell lines at the G0/G1 phase. CCI-779 and rapamycin were equally effective in HL cell lines. Cell cycle arrest was not followed by apoptosis but rather by autophagy, as evident by the increase of acidic autophagic intracellular organelles. On the molecular level, mTOR inhibition by CCI-779 dephosphorylated the downstream ribosomal S6 in all HL cell lines, but had no significant effect on AKT or phospho AKT. Cell cycle arrest was attributed to the upregulation of p27, but cyclin D1 remained unchanged. CCI-779 also enhanced the antiproliferative effect of the PI3K inhibitor LY294002, but did not change the effect of doxorubicin chemotherapy. Conclusions: Inhibition of mTOR by CCI-779 or rapamycin in HL cell lines has antiproliferative effect, by inducing cell cycle arrest followed by autophagy. CCI-779 enhances the activity of PI3K inhibitor LY294002. These data suggest that CCI-779 may have a therapeutic value in patients with HL.

No significant financial relationships to disclose.

A humanized antibody against CD40 (SGN-40) is well tolerated and active in non-Hodgkin’s lymphoma (NHL): Results of a phase I study

7534

Background: CD40 is a member of the TNF receptor family and is widely expressed on hematologic malignancies of B-cell origin. SGN-40 is a humanized antibody against CD40 with effector cell function and mild agonistic activity. Preclinical toxicity studies and efficacy data supported initiation of a multi-institutional phase I study to test the safety, pharmacokinetics, immunogenicity, and efficacy of SGN-40 in patients with relapsed NHL. Methods: Cohorts of 3–6 pts were treated weekly with a maximum dose of 2, 3, or 4 mg/kg/wk SGN-40. A dose escalation schedule is used such that patients receive 1 mg/kg on D1 and D4, 2 mg/kg on D8, and higher doses on weeks 3–5. Responding patients may receive a second cycle. Further dose escalation up to 8 mg/kg is planned. Results: 16 pts have been treated with multiple histologic subtypes: follicular (1), marginal zone (MZL; 1), mantle cell (4), and diffuse large B-cell (DLBCL; 10). One patient (2 mg/kg) developed a reversible Grade 3 unilateral conjunctivitis and ipsilateral loss of visual acuity. No other dose limiting toxicity has been observed up to 4 mg/kg. Preliminary pharmacokinetic data suggest that the antibody has a relatively short half-life, perhaps reflecting a route of elimination or binding that is not saturated at current doses. Two partial responses have been observed at 3 mg/kg (1 MZL, 1 DLBCL) and one partial response has been observed at 4 mg/kg dose (DLBCL relapsed after autologous stem cell transplant with small volume tumor). Conclusions: Using an intra-patient dose escalation schedule, SGN-40 has been well-tolerated at doses up to 4 mg/kg/wk. Further dose-escalation is ongoing to determine the maximum tolerated dose. Three objective responses have been seen, including two in patients with extensively treated aggressive disease. Correlative studies are underway measuring soluble CD40, cytokine release, effect of FcR polymorphisms, and SGN-40-induced immunogenicity. Given the favorable tolerability and activity, phase II studies in NHL are planned.

[Table: see text]

The mTOR inhibitor CCI-779 (temsirolimus) downregulates p21 and induces cell cycle arrest and autophagy in mantle cell lymphoma (MCL)

7573

Background: Mantle cell lymphoma (MCL) is a distinct type of B-cell lymphoma associated with transient response to conventional chemotherapy, continuous relapses and median survival of only 3–4 years. The mammalian target of rapamycin (mTOR) pathway is activated in many human malignancies where it regulates cyclin D1 translation. In a phase II trial, temsirolimus (CCI-779), an inhibitor of mTOR kinase used as single agent achieved an overall response rate of 38% in relapsed MCL patients. Our goal was to determine the activity and the mechanism of action of CCI-779 in MCL cell lines and to examine whether CCI-779 may synergizes with proteasome inhibitors. Methods: The activity of CCI-779 was determined in 3 mantle cell lymphoma cell lines (Jeko 1, Mino, Sp 53). Cell viability was determined by MTS assay, and autophagy by Acridine orange. Analysis of cell cycle was performed by flow cytometry and apoptosis by Annexin-V binding. Molecular changes were determined by western blot . Results: CCI-779 induced cell growth arrest in all cell lines in a time and dose dependent manner. The antiproliferative activity was due to cell cycle arrest in the G0/G1 phase followed by autophagy. CCI-779 decreased S6 phosphorylation in Jeko 1,Sp 53 indicative of mTOR inhibition. Furthermore, CCI-779 downregulated p21 expression in all three cell lines, without altering p 27 expression. Moreover, CCI-779 decreased the expression of the antiapoptotic protein cFLIP and ERK in both Jeko1 and Sp 53, but had no effect on cyclin D1 expression. The proteasome inhibitor bortezomib was also effective in all MCL cell lines, but failed to demonstrate significant synergy with CCI-779. Conclusions: The antiproliferative activity of CCI-779 in MCL is mediated by p21 downregulation and autophagy, without significant effect on cyclin D1 expression. The lack of synergy between bortezomib and CCI-779 should be confirmed using fresh MCL tumor cells.

No significant financial relationships to disclose.