Phase Ib and Expansion Study of Gemcitabine, Nab-Paclitaxel, and Ficlatuzumab in Patients With Metastatic Pancreatic Cancer.

BACKGROUND: In preclinical pancreatic ductal adenocarcinoma (PDAC) models, inhibition of hepatocyte growth factor (HGF) signaling using ficlatuzumab, a recombinant humanized anti-HGF antibody, and gemcitabine reduced tumor burden. METHODS: Patients with previously untreated metastatic PDAC enrolled in a phase Ib dose escalation study with 3 + 3 design of 2 dose cohorts of ficlatuzumab 10 and 20 mg/kg administered intravenously every other week with gemcitabine 1000 mg/m2 and albumin-bound paclitaxel 125 mg/m2 given 3 weeks on and 1 week off. This was followed by an expansion phase at the maximally tolerated dose of the combination. RESULTS: Twenty-six patients (sex, 12 male:14 female; median age, 68 years [range, 49-83 years]) were enrolled, 22 patients were evaluable. No dose-limiting toxicities were identified (N = 7 pts) and ficlatuzumab at 20 mg/kg was chosen as the maximum tolerated dose. Among the 21 patients treated at the MTD, best response by RECISTv1.1: 6 (29%) partial response, 12 (57%) stable disease, 1 (5%) progressive disease, and 2 (9%) not evaluable. Median progression-free survival and overall survival times were 11.0 months (95% CI, 7.6-11.4 months) and 16.2 months (95% CI, 9.1 months to not reached), respectively. Toxicities attributed to ficlatuzumab included hypoalbuminemia (grade 3, 16%; any grade, 52%) and edema (grade 3, 8%; any grade, 48%). Immunohistochemistry for c-Met pathway activation demonstrated higher tumor cell p-Met levels in patients who experienced response to therapy. CONCLUSION: In this phase Ib trial, ficlatuzumab, gemcitabine, and albumin-bound paclitaxel were associated with durable treatment responses and increased rates of hypoalbuminemia and edema.

Q-TWiST Analysis of Tivozanib Versus Sorafenib in Patients With Advanced Renal Cell Carcinoma in the TIVO-3 Study.

BACKGROUND: In TIVO-3, tivozanib increased progression-free survival with no difference in overall survival relative to sorafenib as third- or fourth-line therapy in patients with metastatic renal cell carcinoma. We applied quality-adjusted time without symptoms of disease and toxicity (Q-TWiST) methods to quantify the net health benefits of tivozanib, in the presence of similar survival, when compared with sorafenib. METHODS: The mean Q-TWiST was calculated by applying utility coefficients of 0.5, 1.0, and 0.5 to the 36-month restricted mean health states of time with toxicity (TOX), TWiST, and time after progression/relapse, respectively. The relative Q-TWiST gain was defined as the mean absolute Q-TWiST difference divided by the sorafenib mean overall survival. RESULTS: The mean TWiST was longer for tivozanib than for sorafenib, mean time after progression/relapse was shorter for tivozanib, with no difference in mean TOX. Mean Q-TWiST was 15.04 months and 12.78 months for tivozanib and sorafenib, respectively (P = .0493). The tivozanib relative gain was 11.2%. DISCUSSION: Tivozanib increased Q-TWiST relative to sorafenib, primarily through an increase in TWiST, which is generally considered to be the highest utility state. CONCLUSION: Q-TWiST may be considered an alternative patient-centered measure of benefit of tivozanib in as a third- or fourth-line therapy in patients with renal cell carcinoma. CLINICAL TRIAL INFORMATION: NCT02627963.

Final Overall Survival Results from a Phase 3 Study to Compare Tivozanib to Sorafenib as Third- or Fourth-line Therapy in Subjects with Metastatic Renal Cell Carcinoma.

Tivozanib is a potent and selective inhibitor of the VEGF receptor. In an open-label, randomized phase 3 trial, we compared tivozanib to sorafenib in patients with metastatic renal cell carcinoma (mRCC) who had received two or three prior therapies. We have previously reported that the study met its primary endpoint, demonstrating an improvement in progression-free survival with tivozanib versus sorafenib (5.6 mo vs 3.9 mo; hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.56-0.94; p=0.016). The current report reflects the final assessment of overall survival, showing no difference between treatment with tivozanib and sorafenib (HR 0.97, 95% CI 0.75-1.24). Given its activity and distinct tolerability profile, tivozanib represents a treatment option for patients with previously treated mRCC. PATIENT SUMMARY: We show that tivozanib, a targeted therapy, can delay tumor growth relative to an already approved targeted therapy (sorafenib) in patients with kidney cancer who have received two or three prior treatments. No difference in survival was observed.

Tivozanib versus sorafenib in patients with advanced renal cell carcinoma (TIVO-3): a phase 3, multicentre, randomised, controlled, open-label study.

BACKGROUND: Treatment for renal cell carcinoma has been revolutionised by inhibitors of VEGF receptor. Previous studies have suggested that treatment with a VEGF receptor (VEGFR) tyrosine kinase inhibitor might be effective in patients who had previous checkpoint inhibitor therapy. Therefore, TIVO-3 was designed to compare the efficacy and safety of tivozanib (a potent and selective VEGFR inhibitor) with those of sorafenib as third-line or fourth-line therapy in patients with metastatic renal cell carcinoma. METHODS: In this open-label, randomised, controlled trial done at 120 academic hospitals in 12 countries, we enrolled eligible patients older than 18 years with histologically or cytologically confirmed metastatic renal cell carcinoma and at least two previous systemic treatments (including at least one previous treatment with a VEGFR inhibitor), measurable disease according to the Response Evaluation Criteria in Solid Tumors version 1.1, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were excluded if they had received previous treatment with tivozanib or sorafenib. Patients were stratified by International Metastatic Renal Cell Carcinoma Database Consortium risk category and type of previous therapy and randomised (1:1) with a complete permuted block design (block size of four) to either tivozanib 1·5 mg orally once daily in 4-week cycles or sorafenib 400 mg orally twice daily continuously. Investigators and patients were not masked to treatment. The primary endpoint was progression-free survival by independent review in the intention-to-treat population. Safety analyses were done in all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02627963. FINDINGS: Between May 24, 2016, and Aug 14, 2017, 350 patients were randomly assigned to receive tivozanib (175 patients) or sorafenib (175 patients). Median follow-up was 19·0 months (IQR 15·0-23·4). Median progression-free survival was significantly longer with tivozanib (5·6 months, 95% CI 5·29-7·33) than with sorafenib (3·9 months, 3·71-5·55; hazard ratio 0·73, 95% CI 0·56-0·94; p=0·016). The most common grade 3 or 4 treatment-related adverse event was hypertension (35 [20%] of 173 patients treated with tivozanib and 23 [14%] of 170 patients treated with sorafenib). Serious treatment-related adverse events occurred in 19 (11%) patients with tivozanib and in 17 (10%) patients with sorafenib. No treatment-related deaths were reported. INTERPRETATION: Our study showed that tivozanib as third-line or fourth-line therapy improved progression-free survival and was better tolerated compared with sorafenib in patients with metastatic renal cell carcinoma. FUNDING: AVEO Oncology.

Convection-enhanced delivery of topotecan into diffuse intrinsic brainstem tumors in children.

Convection-enhanced delivery (CED) for the treatment of malignant gliomas is a technique that can deliver chemotherapeutic agents directly into the tumor and the surrounding interstitium through sustained, low-grade positive-pressure infusion. This allows for high local concentrations of drug within the tumor while minimizing systemic levels that often lead to dose-limiting toxicity. Diffuse intrinsic pontine gliomas (DIPGs) are universally fatal childhood tumors for which there is currently no effective treatment. In this report the authors describe CED of the topoisomerase inhibitor topotecan for the treatment of DIPG in 2 children. As part of a pilot feasibility study, the authors treated 2 pediatric patients with DIPG. Stereotactic biopsy with frozen section confirmation of glial tumor was followed by placement of bilateral catheters for CED of topotecan during the same procedure. The first patient underwent CED 210 days after initial diagnosis, after radiation therapy and at the time of tumor recurrence, with a total dose of 0.403 mg in 6.04 ml over 100 hours. Her Karnofsky Performance Status (KPS) score was 60 before CED and 50 posttreatment. Serial MRI initially demonstrated a modest reduction in tumor size and edema, but the tumor progressed and the patient died 49 days after treatment. The second patient was treated 24 days after the initial diagnosis prior to radiation with a total dose of 0.284 mg in 5.30 ml over 100 hours. Her KPS score was 70 before CED and 50 posttreatment. Serial MRI similarly demonstrated an initial modest reduction in tumor size. The patient subsequently underwent fractionated radiation therapy, but the tumor progressed and she died 120 days after treatment. Topotecan delivered by prolonged CED into the brainstem in children with DIPG is technically feasible. In both patients, high infusion rates (> 0.12 ml/hr) and high infusion volumes (> 2.8 ml) resulted in new neurological deficits and reduction in the KPS score, but lower infusion rates (< 0.04 ml/hr) were well tolerated. While serial MRI showed moderate treatment effect, CED did not prolong survival in these 2 patients. More studies are needed to improve patient selection and determine the optimal flow rates for CED of chemotherapeutic agents into DIPG to maximize safety and efficacy. Clinical trial registration no.: NCT00324844.

Concurrent cetuximab, cisplatin, and concomitant boost radiotherapy for locoregionally advanced, squamous cell head and neck cancer: a pilot phase II study of a new combined-modality paradigm.

PURPOSE: Cetuximab is a chimeric monoclonal antibody that targets the epidermal growth factor receptor. Cetuximab has activity in squamous cell carcinoma and enhances both chemotherapy and radiotherapy. We conducted a pilot phase II study of a new combined-modality paradigm of targeted therapy (cetuximab) with chemoradiotherapy. PATIENTS AND METHODS: Eligible patients had stage III or IV, M0, squamous cell head and neck cancer. Treatment included concomitant boost radiotherapy (1.8 Gy/d weeks 1 to 6; boost: 1.6 Gy 4 to 6 hours later weeks 5 to 6; 70 Gy total to gross disease), cisplatin (100 mg/m2 intravenously weeks 1 and 4), and cetuximab (400 mg/m2 intravenously week 1, followed by 250 mg/m2 weeks 2 to 10). RESULTS: Twenty-two patients were enrolled (median age, 57 years; range, 41 to 72 years; median Karnofsky status, 90%; range, 70% to 90%; oropharynx primary tumor, 59% of patients; T4, 36%; N2/3, 77%; stage IV disease, 86%). One patient did not receive study treatment because of an ineligible diagnosis. The severity of expected, acute toxicities was typical of concurrent cisplatin and radiotherapy alone. Grade 3 or 4 cetuximab-related toxicities included acne-like rash (10%) and hypersensitivity (5%). However, the study was closed for significant adverse events, including two deaths (one pneumonia and one unknown cause), one myocardial infarction, one bacteremia, and one atrial fibrillation. With a median follow-up of 52 months, the 3-year overall survival rate is 76%, the 3-year progression-free survival rate is 56%, and the 3-year locoregional control rate is 71%. CONCLUSION: This regimen is not currently recommended outside of the clinical trial setting. Further investigation of its safety profile is needed. However, preliminary efficacy is encouraging, and further development of this targeted combined-modality paradigm is warranted.

Phase I/IIa study of cetuximab with gemcitabine plus carboplatin in patients with chemotherapy-naive advanced non-small-cell lung cancer.

PURPOSE: This multicenter, open-label, phase I/IIa study was undertaken to establish the safety/toxicity profile of cetuximab in combination with gemcitabine and carboplatin in patients with chemotherapy-naïve, epidermal growth factor receptor-positive, stage IV non-small-cell lung cancer. Secondary objectives were to gather preliminary evidence of efficacy including tumor response rate, time to progression, and overall survival. PATIENTS AND METHODS: Thirty-five patients received a total of 264 3-week cycles of treatment with cetuximab, carboplatin, and gemcitabine. An initial dose of cetuximab 400 mg/m2 intravenously was administered the first week, followed by weekly doses of 250 mg/m2. Carboplatin (area under the curve = 5, day 1) and gemcitabine 1,000 mg/m2 on days 1 and 8 were administered every 3 weeks. Patients were evaluated for tumor response after every two cycles of therapy. RESULTS: The most frequently reported adverse events related to cetuximab included an acne-like rash (88.6%), dry skin (34.3%), asthenia and skin disorders (31.4%), mucositis/stomatitis (25.7%), fever/chills (20%), and nausea/vomiting (17.1%). The majority of these toxicities were mild to moderate. One patient withdrew from the study because of a grade 3 allergic reaction. Myelosuppression was the most frequently observed toxicity related to chemotherapy. Responses among 35 assessable patients included 10 partial responses (28.6%). Twenty-one patients had stable disease. The median time to progression was 165 days, and the median overall survival was 310 days. CONCLUSION: The combination of cetuximab, carboplatin, and gemcitabine was well tolerated with an acceptable toxicity profile. Most grade 3 adverse events were attributable to chemotherapy. The response rate and median survival are encouraging and warrant additional investigation.

Multicenter phase I/II study of cetuximab with paclitaxel and carboplatin in untreated patients with stage IV non-small-cell lung cancer.

PURPOSE: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have demonstrated antitumor activity in patients with non-small-cell lung cancer (NSCLC). This study examined the safety profile of the monoclonal antibody EGFR inhibitor, cetuximab, when added to paclitaxel and carboplatin in untreated patients with stage IV NSCLC. Secondary objectives included efficacy and paclitaxel and carboplatin pharmacokinetics during cetuximab treatment. PATIENTS AND METHODS: Patients with tumor evidence of EGFR by immunohistochemistry, performance status of 0 to 2, and measurable disease received paclitaxel 225 mg/m2 with carboplatin area under the curve = 6 on day 1 every 3 weeks. Cetuximab was administered at 400 mg/m2, 1 week before paclitaxel and carboplatin, then weekly at 250 mg/m2. The regimen continued until disease progression or intolerable toxicity. RESULTS: Thirty-one of 32 enrolled patients were treated. The most common cetuximab toxicity was rash in 84% of patients (grade 3 in 13%). Pharmacokinetic sampling did not reveal an interaction between carboplatin, paclitaxel, and cetuximab. An objective response was observed in eight patients (26%). With a median follow-up of 19 months, the median time to progression was 5 months, median survival was 11 months, and the 1- and 2-year survival rates were 40% and 16%, respectively. CONCLUSION: The combination of cetuximab, paclitaxel, and carboplatin was safe and well tolerated in this population of stage IV patients. The response rate, time to progression, and median survival were slightly superior to historical controls treated with paclitaxel and carboplatin alone. A randomized phase II trial has completed accrual.

Amifostine for children with medulloblastoma treated with cisplatin-based chemotherapy.

In adult patients, amifostine appears to ameliorate cisplatin-related nephrotoxicity and ototoxicity. We assessed the safety and efficacy of amifostine in 11 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor treated with radiotherapy and vincristine, lomustine, and cisplatin. Amifostine was administered immediately prior to and 4 hr into the cisplatin infusion. Amifostine caused assymptomatic hypotension and hypocalcemia in 18 and 82% of patients, respectively. Despite amifostine use, 78% of patients developed significant ototoxicity. Although relatively well tolerated, amifostine does not appear to have a major impact on ameliorating the risk of developing significant nephro- and ototoxicity in children with medulloblastoma. Larger studies will help clarify these findings.

Cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor, in combination with gemcitabine for advanced pancreatic cancer: a multicenter phase II Trial.

PURPOSE: To determine the response rate, time to disease progression, survival duration and rate, and toxicity with the combination of cetuximab and gemcitabine in patients with epidermal growth factor receptor (EGFR)-expressing advanced pancreatic cancer. PATIENTS AND METHODS: Patients with measurable locally advanced or metastatic pancreatic cancer who had never received chemotherapy for their advanced disease and had immunohistochemical evidence of EGFR expression were eligible for the multicenter phase II trial. Patients were treated with cetuximab at an initial dose of 400 mg/m(2), followed by 250 mg/m(2) weekly for 7 weeks. Gemcitabine was administered at 1,000 mg/m(2) for 7 weeks, followed by 1 week of rest. In subsequent cycles, cetuximab was administered weekly, and gemcitabine was administered weekly for 3 weeks every 4 weeks. RESULTS: Sixty-one patients were screened for EGFR expression, 58 patients (95%) had at least 1+ staining, and 41 were enrolled onto the trial. Five patients (12.2%) achieved a partial response, and 26 (63.4%) had stable disease. The median time to disease progression was 3.8 months, and the median overall survival duration was 7.1 months. One-year progression-free survival and overall survival rates were 12% and 31.7%, respectively. The most frequently reported grade 3 or 4 adverse events were neutropenia (39.0%), asthenia (22.0%), abdominal pain (22.0%), and thrombocytopenia (17.1%). CONCLUSION: Cetuximab in combination with gemcitabine showed promising activity against advanced pancreatic cancer. Further clinical investigation is warranted.

Phase II trial of cetuximab in patients with refractory colorectal cancer that expresses the epidermal growth factor receptor.

PURPOSE: To evaluate the antitumor activity and toxicity of single-agent cetuximab in patients with chemotherapy-refractory colorectal cancer whose tumors express the epidermal growth factor receptor. PATIENTS AND METHODS: Phase II, open-label clinical trial. Patients were required to have EGFr expression demonstrated on formalin-fixed paraffin-embedded tumor tissue by immunohistochemical staining before study participation. Patients were required to have received irinotecan, either alone or in a combination regimen, and to have demonstrated clinical failure on this regimen before study entry. Cetuximab was administered weekly by intravenous infusion. The first dose of 400 mg/m(2) was given during the course of 2 hours. Subsequent weekly treatments were given at a dose of 250 mg/m(2) during the course of 1 hour. RESULTS: Fifty-seven eligible patients were treated. All were assessable for toxicity and response. The most commonly encountered grade 3 to 4 adverse events, regardless of relationship to study drug, were an acne-like skin rash, predominantly on the face and upper torso (86% with any grade; 18% with grade 3), and a composite of asthenia, fatigue, malaise, or lethargy (56% with any grade, 9% with grade 3). Two patients (3.5%) experienced grade 3 allergic reactions requiring discontinuation of study treatment. A third patient experienced a grade 3 allergic reaction that resolved, and the patient continued on the study. Neither diarrhea nor neutropenia were dose limiting in any of the 57 patients treated. Five patients (9%; 95% CI, 3% to 19%) achieved a partial response. Twenty-one additional patients had stable disease or minor responses. The median survival in these previously treated patients with chemotherapy-refractory colorectal cancer is 6.4 months. CONCLUSION: Cetuximab on this once-weekly schedule has modest activity and is well-tolerated as a single agent in patients with chemotherapy-refractory colorectal cancer whose tumors express the epidermal growth factor receptor. Further studies of cetuximab will evaluate the use of cetuximab in conjunction with first-line and adjuvant treatments for this disease.

Phase II trial of antiepidermal growth factor receptor antibody C225 in patients with advanced renal cell carcinoma.

Fifty-five patients with metastatic renal cell carcinoma (RCC) were treated on a multicenter, single-arm Phase II trial. Patients received single-agent Cetuximab (C225) administered by intravenous infusion at a loading dose of 400 or 500 mg/m2 followed by weekly maintenance doses at 250 mg/m2. None of the patients treated with C225 achieved either a complete or partial response. The median time to progression was 57 days. The most frequently reported grade 3 or 4 toxicity treatment-related adverse events were acne (17%) and rash or dry skin (4%). The lack of clinical response or suggestion of prolonging time to progression compared to historical data with interferon-alfa supports no further study of single-agent C225 in patients with metastatic RCC.

A phase I study of topotecan as a radiosensitizer for brainstem glioma of childhood: first report of the Children's Cancer Group-0952.

Our purpose was to establish the maximum tolerated dosage (MTD) of daily i.v. topotecan with conventionally fractionated radiotherapy (XRT) for patients with intrinsic pontine glioma of childhood. Topotecan was given as a 30-min i.v. infusion 30-60 min before each XRT treatment given daily for 33 days. Total XRT dose was 59.4 Gy. Dose escalation of topotecan was carried out using a standard phase I design. Dose limiting toxicity (DLT) was defined as an absolute neutrophil count (ANC) of < or =500/mm(3) for > or =7 days; platelets of < or =50,000/mm(3) for > or =7 days; >7 days platelet transfusions; fever and neutropenia (ANC < or =500/mm(3) for > or =7 days); and/or any > or=grade 3 non-hematologic toxicity. In this multi-institutional phase I study, 17 patients <21 years with intrinsic pontine glioma were enrolled. Sixteen patients completed treatment. An ANC < or =500/mm(3) for > or =7 days occurred in 2/5 patients at 0.50 mg/m(2) of topotecan, which was the DLT. The remaining 14 patients received topotecan without experiencing DLT. One patient at 0.40 mg/m(2) died of disease progression while on treatment. There were 6 other grade 4 hematologic events (5 ANCs <500/mm(3), 1 hemoglobin <6. 5 g/dl) not meeting DLT criteria. No significant non-hematologic toxicities were seen. The actuarial median survival time is 15 months (95% confidence interval, 9.6-19 months); 1-year survival is 53%. DLT of daily topotecan with cranial XRT is grade 4 neutropenia for > or =7 days at 0.50 mg/m(2) x 33 (total dosage = 16.5 mg/m(2)); the recommended safe MTD of daily topotecan for further phase II testing is 0.40 mg/m(2) x 33 (total dosage = 13.2 mg/m(2)).

Safety experience with IMC-C225, an anti-epidermal growth factor receptor antibody.

In phase II trials, the anti-epidermal growth factor receptor antibody IMC-C225 did not appear to significantly exacerbate the common toxicities associated with cytotoxic chemotherapy when combined with standard anticancer treatments in patients with colorectal cancer, squamous cell carcinoma of the head and neck, or pancreatic cancer. The most common treatment-related adverse events reported during therapy with IMC-C225 were an acne-like rash and hypersensitivity reactions. The acne-like rash appeared as a sterile, suppurative form of folliculitis, commonly starting on the face, scalp, chest, and upper back. It resolved without scarring once treatment was stopped. Notably, the appearance of acne-like rash, particularly grade 3, was associated with higher treatment responses in patients with refractory colorectal cancer. The hypersensitivity reactions occurred less often than acne-like rash. They responded to standard treatments and were less common after the first dose. In summary, IMC-C225 is generally well tolerated as a single agent and when combined with chemotherapy or radiotherapy and possesses a manageable toxicity profile.

Epidermal growth factor receptor as a therapeutic target in head and neck cancer.

Epidermal growth factor receptor (EGFR) is a cell membrane protein that is overexpressed in almost all head and neck squamous cell carcinomas. Overexpression of EGFR has been associated with a poor prognosis in head and neck tumors as well as many other malignancies. This cell membrane protein has been considered an excellent choice as an antitumor therapeutic target. Preclinical and clinical investigations are currently underway to determine the most appropriate use of anti-EGFR therapies. IMC-C225 is a monoclonal antibody that blocks EGFR function and has shown promising radiosensitizing and chemosensitizing properties in preclinical studies. Additionally, initial phase I/II clinical studies of IMC-C225 in combination with radiotherapy or chemotherapy have suggested that the preclinical findings may translate into promising clinical results in squamous cell carcinoma of the head and neck. Therefore, patients with head and neck carcinomas are being evaluated in phase III studies exploring the combination of IMC-C225 and radiation as well as the combination of IMC-C225 and cisplatin in locally advanced and recurrent disease.

A randomized comparison of native Escherichia coli asparaginase and polyethylene glycol conjugated asparaginase for treatment of children with newly diagnosed standard-risk acute lymphoblastic leukemia: a Children's Cancer Group study.

For this study, 118 children with standard-risk acute lymphoblastic leukemia (ALL) were given randomized assignments to receive native or pegylated Escherichia coli asparaginase as part of induction and 2 delayed intensification phases. Patients treated with pegaspargase had more rapid clearance of lymphoblasts from day 7 and day 14 bone marrow aspirates and more prolonged asparaginase activity than those treated with native asparaginase. In the first delayed intensification phase, 26% of native asparaginase patients had high-titer antibodies, whereas 2% of pegaspargase patients had those levels. High-titer antibodies were associated with low asparaginase activity in the native arm, but not in the pegaspargase arm. Adverse events, infections, and hospitalization were similar between arms. Event-free survival at 3 years was 82%. A population pharmacodynamic model using the nonlinear mixed effects model (NONMEM) program was developed that closely fit the measured enzyme activity and asparagine concentrations. Half-lives of asparaginase were 5.5 days and 26 hours for pegaspargase and native asparaginase, respectively. There was correlation between asparaginase enzymatic activity and depletion of asparagine or glutamine in serum. In cerebrospinal fluid asparagine, depletion was similar with both enzyme preparations. Intensive pegaspargase for newly diagnosed ALL should be tested further in a larger population.