Lisocabtagene maraleucel (liso-cel) as second-line (2L) therapy for R/R large B-cell lymphoma (LBCL) in patients (pt) not intended for hematopoietic stem cell transplantation (HSCT): Primary analysis from the phase 2 PILOT study

7062

Background: Pts with R/R LBCL after first-line (1L) treatment (tx) who are unable to undergo high-dose chemotherapy (HDCT) and HSCT have poor outcomes and limited tx options. PILOT (NCT03483103) evaluated liso-cel, an autologous, CD19-directed chimeric antigen receptor (CAR) T cell product, as 2L tx in pts with R/R LBCL not intended for HSCT. Methods: Eligible pts were adults with R/R LBCL after 1L tx who were not deemed candidates for HDCT and HSCT by their physician and met ≥ 1 frailty criteria: age ≥ 70 yr, ECOG PS = 2, DLCO ≤ 60%, LVEF < 50%, CrCl < 60 mL/min, or ALT/AST > 2 × ULN. Bridging tx was allowed. Pts received lymphodepletion with cyclophosphamide and fludarabine, followed 2–7 days later by liso-cel at a target dose of 100 × 106 CAR+ T cells. Cytokine release syndrome (CRS) was graded per Lee 2014 criteria and neurological events (NE) per NCI CTCAE, version 4.03. Primary endpoint was ORR per independent review committee (IRC); all pts had ≥ 6 mo follow-up (f/u) from first response. Results: Of 74 pts leukapheresed, 61 received liso-cel and 1 received nonconforming product. Common reasons for pre-infusion dropout included death and loss of eligibility (5 each). For liso-cel–treated pts, median age was 74 yr (range, 53–84; 79% ≥ 70 yr) and 69%, 26%, and 5% met 1, 2, and 3 frailty criteria, respectively; 26% had ECOG PS = 2 and 44% had HCT-CI score ≥ 3. After 1L tx, 54% were chemotherapy refractory, 21% relapsed ≤ 12 mo, and 25% relapsed > 12 mo; 51% of pts received bridging chemotherapy. Median (range) on-study f/u was 12.3 mo (1.2–26.5). ORR and CR rate was 80% and 54%, respectively. Median DOR and PFS was 12.1 mo and 9.0 mo, respectively. Median OS has not been reached (Table). Most frequent tx-emergent AEs (TEAE) were neutropenia (51%), fatigue (39%), and CRS (38%), with grade (gr) 3 CRS in 1 pt (2%) and no gr 4/5 CRS. Any-grade NEs were seen in 31%, gr 3 in 5% (n = 3), and no gr 4/5 NEs; 7% received tocilizumab, 3% corticosteroids, and 20% both for tx of CRS/NEs. Overall, gr ≥ 3 TEAEs occurred in 79%, with gr 5 in 2 pts (both due to COVID-19). Two pts (3%) had gr 3/4 infections and 15 (25%) had gr ≥3 neutropenia at Day 29. Conclusions: In the PILOT study, liso-cel as 2L tx in pts with LBCL who met ≥ 1 frailty criteria and for whom HSCT was not intended demonstrated substantial and durable overall and complete responses, with no new safety concerns. Clinical trial information: NCT03483103. [Table: see text]

Lisocabtagene maraleucel (liso-cel) as second-line (2L) treatment (tx) for R/R large B-cell lymphoma (LBCL) in patients (pt) not intended for hematopoietic stem cell transplantation (HSCT): Patient-reported outcomes (PRO) from the phase 2 PILOT study

6567

Background: PILOT (NCT03483103) evaluated liso-cel, an autologous, CD19-directed, CAR T cell product, as 2L tx in pts with R/R LBCL not intended for HSCT. We analyzed changes in health-related quality of life (QOL) with respect to functioning and symptoms in PILOT. Methods: Adults with R/R LBCL after first-line tx were eligible. Pts were deemed not candidates for high-dose chemotherapy and HSCT by their physician and met ≥ 1 frailty criteria: age ≥ 70 yr, ECOG PS = 2, DLCO ≤ 60%, LVEF < 50%, CrCl < 60 mL/min, or ALT/AST > 2 × ULN. Pts completed EORTC QLQ-C30, FACT-LymS, and EQ-5D-5L (health utility index [HUI] and VAS) at screening (baseline [BL]), pre-tx (within 7 days before lymphodepletion), preinfusion on day of liso-cel infusion (Day 1), post-tx on Days 29, 60, 90, 180, 270, 365, 545, and 730/end of study, or at PD. The PRO-evaluable set included all pts with BL and ≥ 1 post-BL assessments. Linear mixed-effects models for repeated measures assessed the least squares (LS) mean change from BL for visits with ≥ 10 pts. Meaningful change from BL was calculated using responder definitions (in points): 10 for EORTC QLQ-C30, 3 for FACT-LymS, 0.08 for EQ-5D-5L HUI, and 7 for EQ-VAS. Results: Among the PRO-evaluable set, completion rates were high (≥ 80%) across most visits for all measures. For EORTC QLQ-C30, mean BL fatigue was meaningfully worse than in a general noncancer population (difference of > 10 points). Overall LS mean changes through Day 545 showed significant improvements in EORTC QLQ-C30 fatigue and pain, FACT-LymS, and EQ-VAS (Table). Improvement for lymphoma symptoms was also clinically meaningful. Fatigue improvement was clinically meaningful with a more sensitive minimal important difference of 4 (Cocks et al, 2012). Significant worsening was not observed for any outcome. In individual patient-level analysis, 70% of pts demonstrated meaningful improvement in FACT-LymS at month 6. Conclusions: Liso-cel meaningfully improved fatigue and FACT-LymS scores without negatively impacting other QOL measures. These data support the clinical evidence of liso-cel as a potential new 2L tx in pts with R/R LBCL not intended for HSCT. Clinical trial information: NCT03483103. [Table: see text]

Anakinra (AKR) prophylaxis (ppx) in patients (pts) with relapsed/refractory multiple myeloma (RRMM) receiving orvacabtagene autoleucel (orva-cel)

2537

Background: Orva-cel is a B-cell maturation antigen–targeted chimeric antigen receptor (CAR) T cell therapy being evaluated in the phase 1/2 EVOLVE study (NCT03430011) in pts with RRMM who had at least 3 prior lines of therapy (Tx). We previously reported safety and efficacy in the phase 1 study and established the recommended dose (RD) of orva-cel as 600 × 106 CAR+ T cells (Mailankody et al, ASCO 2020). Cytokine release syndrome (CRS), a dominant toxicity of CAR T cell therapy, is mediated in part by IL-1. We explore the role of ppx with AKR, an IL-1 signaling inhibitor, on reducing the incidence of grade (G) ≥2 CRS after orva-cel treatment at the RD. Methods: Fourteen pts were enrolled sequentially for AKR ppx and treated with orva-cel at the RD. The non-AKR ppx control group comprised the remainder of the phase 1 pts receiving orva-cel at the RD (n = 19). The median follow-up (range) was 3.0 mo (1.8–6.2) for the AKR ppx group and 8.8 mo (5.3–12.2) for the non-AKR ppx group. AKR was administered as 100 mg SC the night before orva-cel infusion, 3 h before the infusion (Day 1), and q24 h on Days 2–5. Dosing was increased to q12 h if CRS developed. CRS was graded by Lee (2014) criteria. Tocilizumab (T) and steroids (S) were used per protocol-specified treatment management guidelines. Results: Disease characteristics and outcomes are shown in the table. In AKR ppx and non-AKR ppx groups, median number of prior regimens was 6 and 5, and bridging Tx was used in 57% and 68% of pts, respectively. The total frequency of CRS was similar in the 2 groups, but with less G 2 in the AKR ppx pts; relative risk (95% CI) = 0.54 (0.21, 1.38). No G ≥3 CRS was seen in either group. The incidence of neurological events (NE), G ≥3 infection, and macrophage activation syndrome/hemophagocytic lymphohistiocytosis (MAS/HLH) was similar. T and S use was numerically lower with AKR ppx. Orva-cel expansion kinetics were similar in the 2 groups. All pts had a 2-month efficacy assessment, with ORR in 100% of AKR ppx and 95% of non–AKR ppx pts. Conclusions: In this nonrandomized evaluation of AKR ppx with orva-cel treatment, the incidence of G ≥2 CRS was lower in pts receiving AKR ppx. The use of AKR ppx produced no adverse effect on the incidence of NE, infection, or MAS/HLH, nor on orva-cel expansion or disease response. These results warrant further study of AKR ppx in CAR T cell therapy. Clinical trial information: NCT03430011. [Table: see text]

Pathological assessment of gastrointestinal biopsies from patients with idelalisib-associated diarrhea and colitis

AIM

Idelalisib (IDELA) treatment is associated with diarrhea/colitis (incidence of ∼15% grade ≥3). We performed a retrospective analysis of gastrointestinal biopsies from 29 patients treated with IDELA across nine clinical trials.

METHODS

A central core laboratory performed histopathologic review, immunohistochemistry, and droplet digital PCR viral studies. These results were correlated with tissue immune profiling data and morphologic features per modified Geboes score.

RESULTS

Out of 29 eligible patients with abdominal pain or diarrhea, 24 (82.8%) had reported adverse event terms of diarrhea and/or colitis. Infectious pathogens were detected in 9/29 samples. Most biopsies presented with mixed/inflammatory infiltrates and contained increased numbers of FOXP3⁺ cells versus normal controls.

CONCLUSION

This study revealed evidence of T-cell dysregulation and a substantial infectious component in association with IDELA-related diarrhea/colitis.

SIMPLIFY-1: A Phase III Randomized Trial of Momelotinib Versus Ruxolitinib in Janus Kinase Inhibitor-Naïve Patients With Myelofibrosis

Purpose We evaluated the efficacy and safety of momelotinib, a potent and selective Janus kinase 1 and 2 inhibitor (JAKi), compared with ruxolitinib, in JAKi-naïve patients with myelofibrosis. Patients and Methods Patients (N = 432) with high risk or intermediate-2 risk or symptomatic intermediate-1 risk myelofibrosis were randomly assigned to receive 24 weeks of treatment with momelotinib 200 mg once daily or ruxolitinib 20 mg twice a day (or per label), after which all patients could receive open-label momelotinib. The primary end point was a ≥ 35% reduction in spleen volume at 24 weeks of therapy. Secondary end points were rates of symptom response and effects on RBC transfusion requirements. Results A ≥ 35% reduction in spleen volume at week 24 was achieved by a similar proportion of patients in both treatment arms: 26.5% of the momelotinib group and 29% of the ruxolitinib group (noninferior; P = .011). A ≥ 50% reduction in the total symptom score was observed in 28.4% and 42.2% of patients who received momelotinib and ruxolitinib, respectively, indicating that noninferiority was not met ( P = .98). Transfusion rate, transfusion independence, and transfusion dependence were improved with momelotinib (all with nominal P ≤ .019). The most common grade ≥ 3 hematologic abnormalities in either group were thrombocytopenia and anemia. Grade ≥ 3 infections occurred in 7% of patients who received momelotinib and 3% of patients who received ruxolitinib. Treatment-emergent peripheral neuropathy occurred in 10% of patients who received momelotinib (all grade ≤ 2) and 5% of patients who received ruxolitinib (all grade ≤ 3). Conclusion In JAKi-naïve patients with myelofibrosis, 24 weeks of momelotinib treatment was noninferior to ruxolitinib for spleen response but not for symptom response. Momelotinib treatment was associated with a reduced transfusion requirement.

Phase 3 trial of momelotinib (MMB) vs ruxolitinib (RUX) in JAK inhibitor (JAKi) naive patients with myelofibrosis (MF)

7000

Background: MMB, an oral JAKi, has been shown in early trials to reduce spleen volume, improve disease associated symptoms (Sx) and improve RBC transfusion (Tx) requirements in patients (pts) with MF. This study was designed to test non-inferiority of MMB vs RUX in splenic volume reduction and Sx amelioration, and superiority in Tx requirement, in JAKi naïve MF pts. Methods: Eligibility: MF, IPSS high risk, Int-2, or symptomatic Int-1; palpable spleen ≥5cm; platelets ≥ 50 K/μl, and no Gr ≥2 peripheral neuropathy (PN). Stratification by Tx dependency and platelets (<100, 100-200 and >200 K/μl). Pts were randomized 1:1 to 24 wks of MMB 200 mg qd + RUX placebo or RUX 20 mg bid (or modified per label) + MMB placebo, after which all pts could receive open label MMB. Assessments: spleen volume by MRI, and pt reported Sx using a daily eDiary of modified MPN-SAF Total Sx Score (TSS). Primary endpoint was splenic response rate (SRR; ≥35% reduction in volume from baseline) at 24 wks. Secondary endpoints, evaluated sequentially at 24 wks, were rates of TSS response (≥50% reduction from baseline), RBC Tx independence (TI), RBC Tx dependence (TD) and of RBC Tx . Results: 175 of 215 (81%) and 201 of 217 (93%) pts randomized to MMB and RUX, respectively, completed the 24 wk DB phase. Efficacy results are shown in Table. Most common Gr ≥3 AEs in the DB phase with MMB were thrombocytopenia (7%) and anemia (6%), and with RUX were anemia (23%), thrombocytopenia (5%) and neutropenia (5%). Gr ≥3 infections occurred in 7% of MMB and 3% of RUX pts. Treatment emergent PN occurred in 22 (10%) of MMB (all Gr ≤2) and 10 (5%) of RUX (9 Gr ≤2, 1 Gr 3) pts in DB phase, none discontinuing study drug for PN. Overall, AEs led to study drug D/C in 13% of MMB and 6% of RUX pts in DB phase. Conclusions: In pts with JAKi naive MF, 24 weeks of MMB is non-inferior to RUX for spleen response but not for symptom response. MMB treatment is associated with a reduced transfusion requirement. NCT01969838. [Table: see text]

A phase II study of the selective phosphatidylinositol 3-kinase delta (PI3Kδ) inhibitor idelalisib (GS-1101) in combination with rituximab (R) in treatment-naive patients (pts) ≥65 years with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL)

7005

Background: PI3K-delta is critical for activation, proliferation and survival of B cells and plays a role in homing and retention in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib is a first-in-class, selective oral inhibitor of PI3Kδ. When combined with R in 19 relapsed/refractory patients with CLL, the ORR was 78% (Coutre, ASH 2012). Methods: Treatment-naive pts ≥65 yrs with CLL or SLL were treated with R 375 mg/m2 weekly x 8 and idelalisib 150 mg bid continuously for 48 weeks (primary study). Pts completing 48 wks w/o progression could continue to receive idelalisib on an extension study. Responses and progression were based on investigator assessment using IWCLL criteria (Hallek, Blood 2008). Results: Data is presented here on the first 50 of 64 pts enrolled, 48 CLL/2 SLL, median age 71 yrs (range: 65-89), M/F 70/30 (%), Rai stage III/IV 10/32 (%), nodes ≥5 cm in 16%, WHO 0/1/2 in 34/64/2 (%); del(17p) in 6 pts and del(11q) in 13 pts. 32 pts completed 48 wks (18 discontinued, 11 due to AE, 4 due to death and 3 other); 30 pts entered the extension study and 26 remain on treatment. The median time on treatment was 16 months (range 0.8-27.5). The ORRwas 96% with 4% nonevaluable; median time to response was 1.9 mos (range 1.0-6.5). There have been no on-study relapses. The Kaplan-Meier estimated PFS is 91% at 24 mos. Of note, 6/6 pts with del(17p) responded (1 CR, 5 PR) and 3 remain on treatment for more than 21 months. 13/14 (93%) pts with thrombocytopenia and 12/12 (100%) pts with anemia at baseline responded. Of 20 pts with B symptoms at baseline, 13 (65%) were asymptomatic by 8 wks. Most frequent AEs (total%/ ≥G3%) were diarrhea (including reported as colitis) (46/16), pyrexia (42/4), chills (34/0), fatigue (34/2), rash (34/10), pneumonia (30/20) and nausea (28/0). Elevated ALT/AST was seen in 60%, Gr ≥3 in 22%. Conclusions: Idelalisib + R is highly active, resulting in durable disease control in treatment-naïve older pts with CLL. These results support the further development of idelalisib in frontline CLL. Clinical trial information: NCT01203930.

A phase III, randomized, controlled study evaluating the efficacy and safety of idelalisib (GS-1101) in combination with ofatumumab for previously treated chronic lymphocytic leukemia (CLL)

TPS7131

Background: PI3K-delta is critical for activation, proliferation and survival of B cells and plays a role in homing and retention in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib is a first-in-class, selective, oral inhibitor of PI3Kδ that reduces proliferation, enhances apoptosis, and inhibits homing and retention of malignant B cells in lymphoid tissues (Lannutti et al, 2011). Ofatumumab (O) is an anti-CD20 monoclonal antibody approved for the treatment of pts with CLL refractory to fludarabine and alemtuzumab. Phase 1 studies demonstrated that idelalisib, as monotherapy or combined with O, is highly active in pts with heavily pretreated CLL: pts experienced profound and rapid regression of lymphadenopathy, reductions in disease-associated chemokines, and durable clinical benefit with an acceptable safety profile (Furman et al, 2012). Methods: This study will enroll 210 pts with CLL previously treated with a purine analog and/or bendamustine, with measurable lymphadenopathy who require treatment for CLL and have disease that is not refractory to ofatumumab, and are expected to benefit from a change in therapy because of CLL progression <24 months since completion of their last prior treatment. Pts are randomized in a 2:1 ratio (Arm A:Arm B). In Arm A, pts receive idelalisib at 150 mg BID continuously in combination with 12 infusions of O at 1000 mg over ~24 weeks (weekly x 8 then monthly x 4). In Arm B, pts receive 12 infusions of O at 2,000 mg over ~24 weeks. Stratification factors address IGHV mutational status, del(17p)/p53 mutation status, and refractory vs relapsed disease. The primary study endpoint is PFS. Secondary endpoints include ORR, lymph node response rate, CR rate, and OS. This is an event-driven trial and primary endpoint evaluation will be based on independent central review. For the primary efficacy analysis, the difference in PFS between the treatment arms will be assessed in the ITT analysis set using Kaplan-Meier methods and the stratified log-rank test. The study opened for enrollment in Dec 2012. Clinical trial information: NCT01659021.

Multicenter phase I trial of the mitogen-activated protein kinase 1/2 inhibitor BAY 86-9766 in patients with advanced cancer

PURPOSE

To evaluate the safety, pharmacokinetics, and pharmacodynamics of BAY 86-9766, a selective, potent, orally available, small-molecule allosteric inhibitor of mitogen-activated protein kinase 1/2 in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

BAY 86-9766 was administered orally daily in 28-day courses, with doses escalated to establish the maximum-tolerated dose (MTD). An expanded cohort was evaluated at the MTD. Pharmacokinetic and pharmacodynamic parameters were assessed, with extracellular signal-regulated kinase (ERK) phosphorylation evaluated in paired biopsies from a subset of the expanded MTD cohort. Tumor specimens were evaluated for mutations in select genes.

RESULTS

Sixty-nine patients were enrolled, including 20 patients at the MTD. The MTD was 100 mg given once-daily or in two divided doses. BAY 86-9766 was well-tolerated. The most common treatment-related toxicities were acneiform rash and gastrointestinal toxicity. BAY 86-9766 was well-absorbed after oral administration (plasma half-life ~12 hours), and displayed dose proportional pharmacokinetics throughout the tested dose range. Continuous daily dosing resulted in moderate accumulation at most dose levels. BAY 86-9766 suppressed ERK phosphorylation in biopsied tissue and tetradecanoylphorbol acetate-stimulated peripheral blood leukocytes. Of 53 evaluable patients, one patient with colorectal cancer achieved a partial response and 11 patients had stable disease for 4 or more courses. An ocular melanoma specimen harbored a GNAQ-activating mutation and exhibited reduced ERK phosphorylation in response to therapy.

CONCLUSION

This phase I study showed that BAY 86-9766 was well-tolerated, with good oral absorption, dose proportional pharmacokinetics, target inhibition at the MTD, and some evidence of clinical benefit across a range of tumor types.

Phase I study of intravenous PI3K inhibitor BAY 80-6946: Activity in patients (pts) with advanced solid tumors and non-Hodgkin lymphoma treated in MTD expansion cohorts

3019

Background: BAY 80-6946 (BAY) is a potent and highly selective reversible pan-Class I PI3K inhibitor, previously reported to be tolerated as a 1-hr infusion at a dose of 0.8 mg/kg on days 1, 8 and 15 every 28 days (MTD). Additional pts were treated in MTD expansion cohorts to assess safety, PK, biomarkers and clinical benefit in selected tumor types, as well as safety in Type 2 diabetics. Methods: To date, 23 nondiabetic pts with solid tumors and 5 with follicular lymphoma (FL) received BAY at the MTD, until disease progression or unacceptable toxicity. Tumor types were selected for high frequency of PIK3CA mutation, including breast cancer (BC; 16), endometrial (3), gastric (2), GU transitional cell (1) and ovarian clear cell (1). Partial enrichment for PIK3CA mutation was achieved by analysis of plasma DNA. 3 diabetic pts have been enrolled, at starting dose of 0.4 mg/kg. PK was done after the 1st and 3rd doses. FDG-PET/CT scans were done at baseline and 48 hrs after the 1st dose for pharmacodynamic assessment. Results: Safety and tolerability assessments confirmed MTD. There were no 1st cycle DLTs. Almost all nondiabetic pts had acute Grade 2/3 hyperglycemia (HG) following each dose; at least 10 of them received insulin for 1-3 days post dose. Hypertension (HTN) lasting < 24 hrs was common in pts with preexisting HTN, and manageable. 2 FL pts developed interstitial pneumonitis (IP) after cycles 2 and 3, both responsive to steroids. Diabetic pts tolerated 0.4 mg/kg. Tumor SUVmax consistently fell at 48 hrs. 3 of 4 FL pts had partial response (PR) after 2 cycles, with 2 confirmed PR pts on BAY for 10+ and 8+ mos. 2 BC pts showed PR , 1 confirmed. PIK3CA mutation (n=7) does not appear to correlate with response. Average T1/2 was 36 hrs. Observation of high Cmax in very obese pts led to recommended maximum dose of 65 mg. Conclusions: BAY induced PRs in pts with BC and FL. The acute toxicities of HG in most pts and HTN in some are manageable, and IP has been limited to 2 lymphoma pts and is responsive to steroids. The observed clinical activity of BAY, along with its acceptable safety profile, provide a rationale for the ongoing development of BAY in combination with cytotoxic and targeted agents.

Evaluation of the PI3K inhibitor BAY 80-6946 in hematologic malignancies

e13576

Background: BAY 80-6946 is a new investigational compound that potently inhibits all PI3K Class I isoforms. BAY 80-6946 is under phase 1 clinical evaluation and PRs have been observed in solid tumors (ST) and follicular lymphoma (FL). The present analysis was performed to gain mechanistic insights into the activity of this compound in FL and potentially other hematological malignancies. Methods: Preclinical: The growth-inhibitory activity of BAY 80-6946 on hematological cancer cell lines (n= 32) was determined by the CellTiterGlo assay. GS-1101 (formerly called CAL-101) and cisplatin (CP) were also tested. Clinical: Specimens from subjects enrolled in a BAY 80-6946 Phase 1 trial MTD expansion were used. Levels of various cytokines and chemokines were determined by ELISA or multiplex immunoassay in plasma samples (n= 27) obtained prior to and during BAY 80-6946 treatment of 6 subjects (3 FL + 3 ST). Proteins examined included CXCL13 (involved in B-cell homing) and BAFF (involved in B-cell survival). Tumor tissue was used to determine PTEN expression via IHC and the mutational status of PTEN via sequencing. PIK3CA mutational status was evaluated in tumor tissue and plasma via BEAMing. Results: Preclinical: BAY 80-6946 was more potent on B-cell lymphomas and other hematological cancer cell lines than GS-1101 or CP (median IC50 in μM: BAY 80-6946= 0.49; GS-1101= 37; CP= 2.9). Clinical: Plasma levels of CXCL13 decreased and BAFF increased following BAY 80-6946 administration in all subjects examined (CXCL13 mean change: -58%; p= 0.004; BAFF mean change: +67%; p= 0.042). PTEN expression was lower in FL compared to ST. No mutations in PTEN or PIK3CA were identified in FL. Mutations in PIK3CA were identified in some ST. Conclusions: These preclinical results indicate that the observed early clinical activity of BAY 80-6946 in FL may be due to a direct anti-proliferative effect on malignant B-cells. The plasma chemokine/cytokine results support the possibility that the modulation of factors involved in B-cell homing and survival may play a mechanistic role in mediating this activity. Overall these results support the continued clinical evaluation of BAY 80-6946 in FL and other hematological malignancies.

A pediatric phase I trial and pharmacokinetic study of ispinesib: a Children's Oncology Group phase I consortium study

PURPOSE

To determine the maximum-tolerated dose, dose-limiting toxicities, and pharmacokinetics of the kinesin spindle protein inhibitor ispinesib in pediatric patients with recurrent or refractory solid tumors.

SUBJECTS AND METHODS

Ispinesib was administered as 1-hr intravenous infusion weekly × 3, every 28 days. Cohorts of 3-6 patients were enrolled at 5, 7, 9, and 12 mg/m(2) /dose. Serial plasma samples for pharmacokinetic analyses were obtained after the first dose.

RESULTS

Twenty-four (13 females) patients with a median (range) age of 10 years (1-19) were enrolled in the study. At the 12 mg/m(2) dose level dose-limiting neutropenia occurred in 2/6 patients and hyperbilirubinemia in 1/6 patients, while at the 9 mg/m(2) dose level 1/6 patients had dose-limiting neutropenia. There were no objective responses, but three patients (diagnoses of anaplastic astrocytoma, alveolar soft part sarcoma, and ependymoblastoma) had stable disease for 4-7 courses. There was substantial interpatient variation in drug disposition. The median (range) terminal elimination half-life was 16 (8-44) hr and the plasma drug clearance was 5 (1-14) L/hr/m(2) .

CONCLUSIONS

The maximum tolerated and recommended phase II dose for ispinesib administered weekly × 3 every 28 days for children with solid tumors is 9 mg/m(2) /dose. Plans for a phase II trial in select pediatric solid tumors are in development.

Role of carbonate in the cytotoxicity of carboplatin

Carboplatin, [Pt(NH3)2(CBDCA-O,O')], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is used against ovarian, lung, and other types of cancer. We recently showed (Di Pasqua et al. (2006) Chem. Res. Toxicol. 19, 139-149) that carboplatin reacts with carbonate under conditions that simulate therapy to produce carbonato carboplatin, cis-[Pt(NH3)2(O-CBDCA)(CO3)]2-, 2. We use 13C and 1H NMR and UV-visible absorption spectroscopy to show that solutions containing carboplatin that have been aged in carbonate buffer under various conditions contain 1, 2, and other compounds. We then show that aging carboplatin in carbonate produces compounds that are more toxic to human neuroblastoma (SK-N-SH), proximal renal tubule (HK-2) and Namalwa-luc Burkitt's lymphoma (BL) cells than carboplatin alone. Moreover, increasing the aging time increases the cytotoxicity of the platinum solutions as measured by the increase in cell death. Although HK-2 cells experience a large loss in survival upon exposure to carbonato forms of the drug, they have the highest values of IC50 of the three cell lines studied, so that HK-2 cells remain the most resistant to the toxic effects of the carbonato forms in the culture medium. This is consistent with the well-known low renal toxicity observed for carboplatin in therapy. The uptake rates for normal Jurkat cells (NJ) and cisplatin-resistant Jurkat cells (RJ), measured by inductively coupled plasma mass spectrometry (ICP-MS), are 16.6 +/- 4.2 and 12.3 +/- 4.8 amol of Pt h-1 cell-1, respectively, when exposed to carboplatin alone. However, when these cells are exposed to carboplatin that has been aged in carbonate media, normal Jurkat cells strongly bind/take up Pt at a rate of 14.5 +/- 4.1 amol of Pt h-1 cell-1, while resistant cells strongly bind/take up 5.1 +/- 3.3 amol of Pt h-1 cell-1. Collectively, these studies show that carboplatin carbonato species may play a major role in the cytotoxicity and uptake of carboplatin by cells.

Teaching teachers about childhood cancer: the effects of a web-based training program

The purpose of this study was to examine the utility and acceptability of a modular computer-based training program on childhood cancer (eg, acute and late effects of treatment, intervention strategies) for teachers. A within-subjects design was implemented with 41 teachers and teachers in training. Participants completed tests of childhood cancer knowledge and application skills both before and after completing the web-based training. An acceptability questionnaire was completed after the training. Results indicated significant gains in knowledge and in case application, as well as high levels of acceptability of the training. It seems that a web-based training program can be accessed by teachers and in 2 to 4 hours can significantly increase cancer knowledge in an acceptable manner.

Modification and uptake of a cisplatin carbonato complex by Jurkat cells

The interactions of Jurkat cells with cisplatin, cis-[Pt(15NH3)2Cl2]1, are studied using 1H-15N heteronuclear single quantum coherence (HSQC) NMR and inductively coupled plasma mass spectrometry. We show that Jurkat cells in culture rapidly modify the monocarbonato complex cis-[Pt(15NH3)2(CO3)Cl]- (4), a cisplatin species that forms in culture media and probably also in blood. Analysis of the HSQC NMR peak intensity for 4 in the presence of different numbers of Jurkat cells reveals that each cell is capable of modifying 0.0028 pmol of 4 within approximately 0.6 h. The amounts of platinum taken up by the cell, weakly bound to the cell surface, remaining in the culture medium, and bound to genomic DNA were measured as functions of time of exposure to different concentrations of drug. The results show that most of the 4 that has been modified by the cells remains in the culture medium as a substance of molecular mass <3 kDa, which is HSQC NMR silent, and is not taken up by the cell. These results are consistent with a hitherto undocumented extracellular detoxification mechanism in which the cells rapidly modify 4, which is present in the culture medium, so it cannot bind to the cell. Because there is only a slow decrease in the amount of unmodified 4 remaining in the culture medium after 1 h, -1.1 +/- 0.4 microM h(-1), the cells subsequently lose their ability to modify 4. These observations have important implications for the mechanism of action of cisplatin.

Activation of carboplatin by carbonate

Carboplatin, [Pt(NH3)2(CBDCA-O,O')], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is in wide clinical use for the treatment of ovarian, lung, and other types of cancer. Because carboplatin is relatively unreactive toward nucleophiles, an important question concerning the drug is the mechanism by which it is activated in vivo. Using [1H,15N] heteronuclear single quantum coherance spectroscopy (HSQC) NMR and 15N-labeled carboplatin, we show that carboplatin reacts with carbonate ion in carbonate buffer to produce ring-opened products, the nature of which depends on the pH of the medium. The assignment of HSQC NMR resonances was facilitated by studying the reaction of carboplatin in strong acid, which also produces a ring-opened product. The HSQC NMR spectra and UV-visible difference spectra show that reaction of carboplatin with carbonate at pH > 8.6 produces mainly cis-[Pt(NH3)2(CO3(-2))(CBDCA-O)]-2, 5, which contains the mono-dentate CBDCA ligand and mono-dentate carbonate. At pH 6.7, the primary product is the corresponding bicarbonato complex, which may be in equilibrium with its decarboxylated hydroxo analogue. The UV-visible absorption data indicate that the pKb for the protonation of 5 is approximately 8.6. Thus, the reaction of carboplatin with carbonate produces a mixture of ring-opened species that are anions at physiological pH. HSQC NMR studies on 15N-labeled carboplatin in RPMI culture media containing 10% fetal bovine serum with and without added carbonate suggest that carbonate is the attacking nucleophile in culture media. However, because the rate of reaction of carbonate with carboplatin at physiological pH is small, NMR peaks for ring-opened carboplatin were not detected with HSQC NMR. The rate of disappearance of carboplatin in culture medium containing 9 x 10(8) Jurkat cells is essentially the same as that in carbonate buffer, indicating that the ring-opening reaction is not affected by the presence of cells. This work shows that carbonate at concentrations found in culture media, blood, and the cytosol readily displaces one arm of the CBDCA ligand of carboplatin to give a ring-opened product, which at physiological pH is a mixture of anions. These ring-opened species may be important in the uptake, antitumor properties, and toxicity of carboplatin.

Phase I clinical and pharmacologic study of weekly cisplatin and irinotecan combined with amifostine for refractory solid tumors

PURPOSE

This Phase I study was designed primarily to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of irinotecan and cisplatin with and without amifostine in children with refractory solid tumors.

PATIENTS AND METHODS

Cisplatin, at a fixed dose of 30 mg/m(2), and escalating doses of irinotecan (starting dose, 40 mg/m(2)) were administered weekly for four consecutive weeks, every 6 weeks. After the MTD of irinotecan plus cisplatin was determined, additional cohorts of patients were enrolled with amifostine (825 mg/m(2)) support. Leukocyte DNA-platinum adducts and pharmacokinetics of cisplatin and WR-1065 (amifostine-active metabolite) were also determined.

RESULTS

Twenty-four patients received 43 courses of therapy. The MTD for irinotecan administered in combination with cisplatin (30 mg/m(2)) was 50 mg/m(2). The DLTs of this combination were neutropenia and thrombocytopenia. With the addition of amifostine, at an irinotecan dose of 65 mg/m(2) and cisplatin dose of 30 mg/m(2), the DLT was hypocalcemia. Although no objective responses were observed, six patients received at least three courses of therapy. The amounts of platinum adducts (mean +/- SD) were 10 +/- 20 molecules/10(6) nucleotides. The maximum plasma concentrations (C(max)) for free cisplatin and WR-1065 were 4.5 +/- 1.6 micro M and approximately 89 +/- 10 micro M, respectively. The half-life (t(1/2)) for free plasma cisplatin was 25.4 +/- 5.4 min. The initial t(1/2) for plasma WR-1065 was approximately 7 min and terminal t(1/2) approximately 24 min.

CONCLUSION

The combination of cisplatin and irinotecan administered weekly for 4 weeks in children with refractory cancer is well tolerated. Amifostine offers some myeloprotection, likely permitting >/=30% dose escalation for irinotecan, when administered in a combination regimen with cisplatin. However, effective antiemetics and calcium supplementation are necessary with the use of amifostine. Further escalation of irinotecan dosing, using these precautions for amifostine administration, may be possible.

Kinetics of cisplatin binding to cellular DNA and modulations by thiol-blocking agents and thiol drugs

DNA platination by cisplatin (CDDP) was investigated in peripheral blood mononuclear cells and ovarian cancer cells using atomic absorption spectroscopy. Plots showing the amount of platinum (Pt) bound to DNA versus the molar concentration of cisplatin in the incubation medium ([CDDP]) were nonlinear. For [CDDP] < about 5 microM, the amount of Pt bound to DNA increased slowly with added drug. However, for larger [CDDP], the slope of the plot increased significantly. To study the role of thiols in affecting cisplatin binding to DNA, cells were treated with N-ethylmaleimide, which modifies thiol groups, rendering them incapable of binding cisplatin. Analysis using high-pressure liquid chromatography showed that approximately 99% of cellular glutathione was modified by N-ethylmaleimide. A plot of the amount of Pt bound to DNA versus [CDDP] for thiol-blocked cells is linear, with a slope similar to that of unblocked cells at high [CDDP]. Neither S-2-(3 aminopropylamino)ethanethiol (WR-1065) nor mesna, when added at clinically achievable concentrations (i.e., < approximately 300 microM), affected DNA platination. However, DNA platination was totally abolished by millimolar concentrations of the drug thiols (approximately 1.25 mM WR-1065 or approximately 5 mM mesna). Thus, the data show that endogenous thiols intercept cellular cisplatin, but this mechanism is less important at high [CDDP]. Moreover, therapeutic concentrations of drug thiols do not significantly affect DNA platination. A simple model that reproduces the experimental results of the amount of cisplatin binding to DNA as a function of [CDDP], time, and thiol content is proposed. The model takes into account passage of cisplatin and thiols through the cell membrane, binding of cisplatin to cellular thiols, and platination of DNA.

Blood thiols following amifostine and mesna infusions, a pediatric oncology group study

The Pediatric Oncology Group study for metastatic Ewing's sarcoma used amifostine and mesna with the alkylating agents. To determine the fate of combined drug thiols, we measured thiol levels in plasma, red blood cells (RBC), and peripheral blood mononuclear cells (PBMC) of four patients. We also conducted analogous measurements on two patients who received mesna alone and a volunteer's blood following in vitro treatment. Thiols were labeled with monobromobimane, separated on high-pressure liquid chromatography, and detected by fluorescence. Incubation of a volunteer's blood with mesna, WR-1065, or both revealed that cellular uptake of total reducible drug was approximately 10% of plasma level for mesna but approximately 60% for WR-1065. Cellular drugs were mainly the thiol form, whereas half of the plasma drugs were disulfides. Combined incubation with both thiols did not change the extent or form of uptake. WR-1065 and mesna prevented glutathione depletion by 4-hydroperoxycyclophosphamide. Results from patients were similar. WR-1065 and mesna appeared in the cells by the end of the drug infusions, although WR-1065 uptake was more efficient than mesna. The concentration-time profiles of mesna in RBC paralleled those in plasma. Amifostine administration during mesna infusion caused transient increase in mesna levels. Both agents increased blood cysteine and decreased total reducible cysteine. Mesna alone and mesna plus amifostine prevented cellular glutathione depletion. In conclusion, mesna is imported by RBC and PBMC, but less efficiently than WR-1065. When present at equal levels, these thiols do not influence each other's uptake. Adequate dosing of either drug is necessary for protecting the cells from toxic effects of alkylating agents.

WR-2721 (amifostine) infusion in patients with Ewing's sarcoma receiving ifosfamide and cyclophosphamide with mesna: drug and thiol levels in plasma and blood cells, a Pediatric Oncology Group study

PURPOSE

Previous WR-2721 human pharmacokinetic studies were limited to plasma levels in patients receiving platinum-based compounds, and none includes the effects of WR-2721 on endogenous thiols. In the present study (Pediatric Oncology Group study no. 9457), we measured the levels of WR-2721, its active metabolites, as well as cysteine and glutathione in whole blood, plasma, and blood cells in patients receiving high-dose alkylating agents with mesna.

METHODS

WR-2721 was administered (15 min intravenous infusion of 825 mg/m(2) per dose x2) to five patients with metastatic Ewing's sarcoma receiving ifosfamide and cyclophosphamide with mesna. Intracellular and extracellular blood thiols were labeled with monobromobimane (mBBr) at the time of collection, and the low molecular weight (LMW) thiols were subsequently separated by HPLC and detected by fluorescence.

RESULTS

The active metabolite of the drug, WR-1065, peaked at 100 microM in plasma and blood cells at the end of WR-2721 infusion and decayed with a rapid initial half-life. Detectable levels of WR-1065 and its LMW disulfides were present in plasma and blood cells at approximately 1 h after the WR-2721 infusion. By the end of the first WR-2721 infusion (prior to mesna infusion), the mean cysteine level more than doubled and the mean Cys-SS-LMW (cystine and the mixed LMW disulfides) level decreased by approximately 50% in both plasma and blood cells. In four of five patients, reduced glutathione levels in blood cells increased by the end of the first WR-2721 infusions, the average increment being approximately 36%.

CONCLUSIONS

(1) WR-1065 is rapidly formed from WR-2721 and equilibrates between plasma and blood cells; (2) WR-1065 decays in plasma and blood cells with similar rapid initial half-lives of approximately 16 min; (3) WR-2721 treatment increases cysteine in plasma and blood cells, an effect similar to that of mesna; (4) WR-2721 treatment appears to increase glutathione levels in blood cells; (5) Mesna does not have a substantial effect on the fate of WR-2721 in patients.

A Phase I trial of bryostatin-1 in children with refractory solid tumors: a Pediatric Oncology Group study

Bryostatin-1, a macrocyclic lactone, appears to elicit a wide range of biological responses including modulation of protein kinase C (PKC). PKC, one of the major elements in the signal transduction pathway, is involved in the regulation of cell growth, differentiation, gene expression, and tumor promotion. Because of the potential for a unique mechanism of interaction with tumorgenesis, a Phase I trial of bryostatin-1 was performed in children with solid tumors to: (a) establish the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD); (b) establish the pharmacokinetic profile in children; and (c) document any evidence of antitumor activity. A 1-h infusion of bryostatin-1 in a PET formulation (60% polyethylene glycol 400, 30% ethanol, and 10% Tween 80) was administered weekly for 3 weeks to 22 children (age range, 2-21 years) with malignant solid tumors refractory to conventional therapy. Doses ranged from 20 to 57 microg/m2/ dose. Pharmacokinetics were performed in at least three patients per dose level. The first course was used to determine the DLT and MTD. Twenty-two patients on five dose levels were evaluable for toxicities. At the 57 microg/m2/dose level dose-limiting myalgia (grade 3) was observed in three patients; two of those patients also experienced photophobia or eye pain, and one experienced headache. Symptoms occurred in all patients within 24-72 h after the second dose of bryostatin-1 with resolution within 1 week of onset. Other observed toxicities (grades 1 and 2) included elevation in liver transaminases, thrombocytopenia, fever, and flu-like symptoms. The bryostatin-1 infusion was typically well tolerated. Although stable disease was noted in several patients, no complete or partial responses were observed. The recommended Phase II dose of bryostatin-1 administered as a 1-h infusion weekly for 3 of every 4 weeks to children with solid tumors is 44 microg/m2/dose. Myalgia, photophobia, or eye pain, as well as headache, were found to be dose limiting.

Determination of the cytoprotective agent WR-2721 (Amifostine, Ethyol) and its metabolites in human blood using monobromobimane fluorescent labeling and high-performance liquid chromatography

PURPOSE

WR-2721 [S-2-(3-aminopropylamino)ethylphosphorothioic acid] is a chemoprotective agent that is currently in pediatric clinical trials. It is a prodrug that is dephosphorylated by alkaline phosphatase to the active free thiol form, WR-1065 [S-2-(3-aminopropylamino)ethanethiol]. It is likely that adequate and sustained cellular levels of the drug are necessary for optimum cytoprotection. To date, a method to measure both plasma and cellular levels of WR-2721 and its metabolites in clinical samples has not been available.

METHODS

In the study reported here the monobromobimane (mBBr) fluorescent labeling method was used to measure these levels when drug was added in vitro to blood samples from normal volunteers. In addition, we present pharmacokinetic data from a pediatric patient receiving WR-2721 (825 mg/m2 x 2).

RESULTS

The results can be summarized as follows: (1) WR-2721 was detected in the patient's plasma with a half-life of about 10 min; (2) the WR-1065 concentration in the blood cellular fraction was similar to that of plasma; (3) both WR-1065 and WR-SS-low molecular weight (WR-SS-LMW) metabolites disappeared from plasma and the cellular fraction by 3.6 h after WR-2721 infusion; (4) a large proportion of WR-1065 was oxidized in plasma to WR-SS protein and WR-SS-LMW; (5) a large proportion of WR-1065 in the cellular fraction was oxidized to WR-SS-protein; (6) the WR-SS-LMW concentration in the cellular fraction was low; and (7) saturation of plasma and cellular protein binding sites was possible.

CONCLUSIONS

The pharmacokinetic data that were generated with this technique could guide clinical trials using WR-2721.

Demyelinating and gliotic cerebellar lesions in Langerhans cell histiocytosis

PURPOSE

To describe the involvement of the cerebellum by a gliotic and demyelinating process in Langerhans cell histiocytosis.

METHODS

A retrospective analysis of all (N = 30) cases of Langerhans cell histiocytosis followed at our institution since 1975 yielded four patients with CT and/or MR evidence of cerebellar abnormalities.

RESULTS

Four patients manifested strikingly similar findings of symmetric nonenhancing hypodensities in the dentate nuclei region of the cerebellum, which were hypointense on short-repetition-time/short-echo-time MR and hyperintense on long-repetition-time/long-echo-time MR. Biopsy in one patient yielded areas of demyelination, cell loss, and gliosis without histiocytic infiltration.

CONCLUSION

Langerhans cell histiocytosis involves the cerebellum in a specific and poorly understood manner. Lesions on imaging may precede clinical findings by years. Lesions may occur in patients who have never experienced radiation therapy and may act as a marker for eventual central nervous system deterioration.

Treatment of recurrent and refractory pediatric solid tumors with high-dose busulfan and cyclophosphamide followed by autologous bone marrow rescue

PURPOSE

The purpose of this study was to determine the toxicities of and responses to high-dose busulfan and cyclophosphamide with autologous bone marrow transplant (ABMT) in patients with recurrent or refractory pediatric solid tumors.

PATIENTS AND METHODS

We treated 18 patients (ages, 2 to 38 years; median, 14) who had tumors that were resistant to conventional chemotherapy and radiotherapy with busulfan 16 mg/kg and cyclophosphamide 200 mg/kg. Seventeen patients received bone marrow purged with 4-hydroperoxycyclophosphamide; one received unpurged marrow.

RESULTS

Despite extensive prior treatment, including radiotherapy in 16 patients, toxicity generally was acceptable. For seven patients with measurable disease, there were three partial responses of 2, 10, and 20 months' duration, three patients with stable disease (SD), and one early, toxic death. Of the 11 patients with no measurable disease at the time of transplantation, one patient with osteosarcoma continues in remission at 57+ months and one third of the patients survived for at least 16 months. Mucositis was the predominant nonhematopoietic toxicity.

CONCLUSION

Although the high-dose busulfan and cyclophosphamide combination showed modest activity, changes in the preparative regimen should be considered to improve the response rate in refractory tumors.

Significance of aberrant immunophenotypes in childhood acute lymphoid leukemia

Leukemic cells from 51 pediatric patients (younger than 18 years) diagnosed with acute lymphoid leukemia by standard morphologic and cytochemical methods were subjected to flow cytometric studies using a panel of monoclonal antibodies against T-cell (CD1, 2, 3, 4, 5, 7, 8), B-cell (CD10, 19, 20, 21), myeloid (CD13, 14, 15, 33), and HLA-DR antigens. Cases of "conventional" acute lymphoid leukemia (leukemic cells with a normal configuration of B-cell or T-cell differentiation antigens) were observed in 26 of 51 (51%) cases, whereas cases of "aberrant" acute lymphoid leukemia (cells with abnormal patterns of B-cell or T-cell antigens or with concomitant myeloid antigens) were noticed in 25 (49%) cases. Myeloid antigen-positive acute lymphoid leukemia was observed in the leukemic cells of eight (16%) individuals. No significant differences were observed between conventional and aberrant ALL in the distribution of sex, age, leukocyte count, hemoglobin concentration, platelet count, blast count, French-American-British (FAB) type, lymphadenopathy, organomegaly, rate or duration of remission, or survival. When only myeloid antigen-positive cases were compared with myeloid antigen negative-cases, no significant correlations were observed except for duration of first remission (myeloid antigen positive, 26+ +/- 22 months; myeloid antigen negative, 40+ +/- 18 months; P less than 0.001), and duration of survival (myeloid antigen positive, 27+ +/- 24 months; myeloid antigen negative, 62+ +/- 17 months; P = 0.001). These data suggest that pediatric patients with ALL blasts possessing myeloid antigens may represent a high-risk group for length of remission and survival.

Intravenous immunoglobulin in the treatment of aplastic anemia

Aplastic anemia is characterized by reduced production of mature erythrocytes, granulocytes, and platelets from marrow stem cells leading to peripheral blood pancytopenia. In many cases, it appears that there is an aberrant immune response suppressing stem cell differentiation and renewal, leading to bone marrow aplasia and the observed peripheral blood pancytopenia. This report describes a patient with aplastic anemia unresponsive to antithymocyte globulin and high-dose steroid therapy who did respond to intravenous immunoglobulin and now has normal peripheral blood counts.

T6 monoclonal antibody reacts with blasts from cases of common antigen acute lymphocytic leukemia

The expression of the T6 antigen on malignant lymphoid cells has been considered strong evidence in support of T-cell lineage and thymic stage of differentiation of the neoplastic cells. Thus, the authors have used the T6 monoclonal antibody for the last three years in the immunophenotyping of blasts from 60 consecutive cases of acute lymphocytic leukemia (ALL) and 8 cases of T-cell lymphoma. Blasts from 12 of 46 (26%) cases of common type ALL, 4 of 7 (57%) cases of T-cell ALL, 2 of 3 (66%) cases of lymphoblastic lymphoma, and 1 of 5 (20%) cases of peripheral (postthymic) T-cell lymphoma were positive for the T6 antigen. The authors conclude that the expression of T6 antigen on malignant lymphoid cells may not always indicate T-cell lineage.

Endothelial cell proliferation may be mediated via the production of endogenous lipoxygenase metabolites

Endogenous regulators of endothelial cell proliferation have not been clearly defined. We investigated whether the cyclooxygenase and/or lipoxygenase metabolites are involved in this process, and report that lipoxygenase products can modulate endothelial cell growth. Nordihydroguaiaretic acid--a lipoxygenase inhibitor, inhibited endothelial cell proliferation as well as DNA synthesis. 5,8,11,14-Eicosatetraynoic acid--an inhibitor of both lipoxygenase and cyclooxygenase also inhibited endothelial cell DNA synthesis, while indomethacin--a selective cyclooxygenase inhibitor did not affect cell proliferation or DNA synthesis. While arachidonic acid stimulated DNA synthesis, this effect was completely abolished by nordihydroguaiaretic acid. These results demonstrate that products of the lipoxygenase pathway can affect endothelial cell proliferation.

Controversy in the management of optic nerve glioma

The records of 16 patients with optic nerve glioma treated between 1961 and 1984 were reviewed. All patients except two had extension of tumor beyond the chiasm to the hypothalamus, adjacent brain and/or along the posterior optic tract. Eleven of 16 cases were biopsy-proven, two patients had craniotomy and visual inspection but no biopsy was performed, and in two cases the biopsy was not diagnostic. Fourteen patients received radiation therapy, usually consisting of 50 Gy in 5 weeks (range 40-56 Gy), one patient was treated surgically and one with chemotherapy. With a follow-up of 1 to 20 years, 7 of the 14 patients irradiated are alive, three patients are dead of disease at 3, 6 and 9 years post-treatment, three were lost to follow-up at 1, 8, and 8 years, and one is dead of intercurrent disease at 5.5 years. Overall vision was improved in five patients and stable in seven following treatment. In two patients, vision could not be evaluated because of young age at presentation. Four patients had recurrences. One was retreated with 30 Gy in 3 weeks and shows no evidence of disease at 20 years. The three other patients died of their disease. There is controversy over the best treatment for these patients. Based on these results and a review of the literature, the authors recommendation is to irradiate tumors with extension beyond the chiasm at the time of presentation rather than waiting for increasing symptoms because function that is lost may not always be recovered. Chemotherapy needs to be further investigated but holds promise, especially for the younger children.

Prognostic significance of mean cell volume in non-Hodgkin's lymphomas

Cell volumes of neoplastic lymphocytes collected from lymph nodes of 53 patients with non-Hodgkin's lymphoma were compared to lymphocytes from 18 patients with reactive hyperplasia. The mean cell volume (MCV) and the modal volume (MV) of neoplastic lymphocytes were larger than the MCV and MV of lymphocytes from reactive hyperplasia. The cell volumes of neoplastic lymphocytes from patients with non-Hodgkin's lymphoma were more heterogeneous within and among cases than observed in volumes from lymphocytes of patients with reactive hyperplasia. The cell volumes of neoplastic lymphocytes corresponded to subgroups within the Rappaport Classification and the Working Formulation. Cell volumes of neoplastic cells from low-grade lymphomas were smaller than intermediate grade lymphomas which in turn were smaller than high-grade lymphomas. When cases of NHL were placed into three subtypes based on the MCV, large cell lymphomas had a significantly shorter survival then small and intermediate cell lymphomas at 12 months. However, a stepwise multiple regression analysis failed to demonstrate any independent value of cell volume in the prediction of survival.

Inhibition of human malignant neuroblastoma cell DNA synthesis by lipoxygenase metabolites of arachidonic acid

In vivo studies have shown that inhibitors of cyclooxygenase metabolism of arachidonic acid may diminish growth and metastasis of certain tumors. Because cyclooxygenase inhibition may increase the production of lipoxygenase products of arachidonic acid metabolism, we have investigated the effect of two such products, 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-hydroxyeicosatetraenoic acid (15-HETE) on tumor cell proliferation in vitro. When neuroblastoma cells (SK-N-SH) in culture were treated with 12-HETE for 18 hr, incorporation of [3H]thymidine was inhibited up to 64% at concentrations from 20 to 50 microM. Under the same conditions, 15-HETE resulted in inhibition of up to 46%, while arachidonic acid had no apparent effect. When evaluated in the presence of serum, 12-HETE at a concentration of 120 microM produced a 20.6 +/- 2.8% (S.E.) inhibition of the increase in total DNA content over 48 hr, while 15-HETE at this concentration produced a 16.5 +/- 5.3% inhibition. We conclude that 12-HETE, the product of platelet lipoxygenase, and 15-HETE, a product of neutrophil and lymphocyte lipoxygenases, can inhibit human neuroblastoma cell growth in vitro and may play a role in the effect of cyclooxygenase inhibitors on tumor growth in vivo.