ALBERT

Description: The better outcome in pediatric ALL may not be solely related to the biology of the disease. Adult regimens are less intensive than used in children and include less, shorter or no use of asparaginase; the drug is often considered more toxic than in children. However, adequate serum asparagine depletion was shown to be associated with improved overall outcome. Further in several, multi-agent, large pediatric randomized trials, longer administration of asparaginase in the post remission phase and more sustained asparagine depletion resulted in better outcome. PEG-asparaginase (PEG-ASP) is a modified E.coli ASP, with less hypersensitivity reactions and longer half-life. In adults a single IV dose of PEG-ASP during induction produces long duration of asparagine depletion of up to 4 weeks, t½ = 7 days, with similar toxicity to equivalent multiple doses of E.coli ASP (Douer et al Blood 19:2744,2007). We now report the use of multiple doses of PEGASP, given during induction and throughout the post-remission phases in order to produce prolonged and sustained asparagine depletion in the context of an intensified pediatric protocol, in newly diagnosed, treatment naïve, adult ALL. Sustained asparaginase activity after the short acting E.coli ASP, can be impaired by development of neutralizing anti – asparaginase antibodies. We therefore measured the asparaginase enzymatic activity in a cohort of our patients who received PEG-ASP which in children was shown to be associated with less antibody formation (Avramis et al Blood2002;99:1986). Methods: The backbone of our protocol is an augmented BFM pediatric ALL regimen consisting of 8 cycles of multi-agent chemotherapy, followed by maintenance. PEG-ASP (2000 U/m2/dose) is given IV once on day 15 of the following cycles (total 6 doses): induction phase I (cycle 1), induction phase II (cycle 2), two cycles of consolidation (cycles 3 and 6), and two cycles of delayed re-induction (cycles 5 and 8). Since December 2006, Ph+ patients receive imatinib 600mg/daily. Asparaginase enzymatic activity was measured in samples obtained before and after PEG-ASP doses in cycles 1, 5 and 8. Results: 41 patients, aged 19–57 (median 33) years, with precursor B cell – 36, T cell-5, Ph+ 9, were studied. Median WBC at diagnosis - 15,900/cumm (range 1,900–512,000). CR rate: 37 (95%) pts. all after induction phase I. To date 15 patients received all 6 doses of PEG-ASP, having completed all consolidation cycles. The other patients are still being treated. So far the number of PEG-ASP doses given is: 6(15pts), 3(6 pts), 2(7 pts), 1(13 pts) Fifteen patients could not continue the protocol for: allogeneic stem-cell transplantation (8), refusal (1), pancreatitis (5), grade 3 DVT(1). Two additional patients died in CR from neutropenic sepsis. Patients with elevated liver enzymes, high bilirubin, or hyperglycemia continued on the study. Total number of PEG-ASP doses was 135. No pt had an allergic reaction. The number of pts with grade 3/4 toxicities during PEG-ASP cycles were: elevated liver enzymes 24 (59%), hyperbilrubinema 8 (20%), hyperglycemia 12 (29 %), pancreatitis 6(15%), fatigue 4(10%), hypertriglyceridemia 3 (7%), catheter thrombosis- 4 (10%), neuropathy-1. All toxicities were reversible. With a median follow up of 18 months, EFS at 3 and 4 yrs is 68 % (Ph- patients 74%) and CIR is 23%. Asparaginase enzymatic activity after each dose was very long in a cohort of 19 pts with a population average of t½ = 10.99 days (peak concentration 0.88 IU/ml). All 74 specimens analyzed from this cohort of patients had significant asparaginase activity after each PEG-ASP dose, highly suggesting that none of the patients analyzed had developed neutralizing anti asparaginase antibodies. Additional patients with enzymatic measurements will be presented Conclusions: Multiple doses of PEG-ASP IV in adults (ages 19–57 years) provide prolonged and sustained asparagine depletion and no apparent drug inactivating by antibody formation. In combination with an intensified BFM-based protocol this pediatriclike strategy is feasible, without allergic reactions, and with acceptable toxicity. Although the follow up is relatively short the EFS appears to be high. Such approach may benefit adults with ALL

Description: Deamination of asparagine (Asn) and glutamine (Gln) by asparaginase (ASNase) induces apoptosis of ALL lymphoblasts, which lack ability to synthesize Asn de-novo. Early treatment intensification after Induction, including PEG-ASNase instead of native E.Coli-ASNase, in addition to more vincristine and intravenous methotrexate, improves outcome in pediatric ALL patients presenting with unfavorable features, who show rapid early response to Induction chemotherapy (Seibel NL, et al., Blood, 2003;102:224a). Erwinase was used for patients with overt clinical allergy to E.Coli-ASNase. We evaluated the population pharmacokinetics and pharmacodynamics (PK-PD) of the three ASNase formulations employed on CCG-1961. The PK-PD parameters of native and PEG-ASNase in this group of HR ALL patients were similar to those reported from SR ALL patients from CCG-1962 (Avramis VI, et al., Blood, 2002;99:1986–1994). Population PK (NONMEM) showed the expected half-lives of native E.Coli-ASNase (6000 IU/m2): 1.3 days; PEG-ASNase (2500 IU/m2): 6.5 days; and Erwinase (6000 IU/m2): 0.8 days. Repeated doses resulted in an accumulation of activity with moderate prolongation of elimination half-lives for all formulations. PEG-ASNase provided 〉 0.3 IU/ml activity for 〉 21 days for most patients in Delayed Intensification. We measured simultaneous amino acid levels in 430 sera samples obtained from various phases of CCG-1961 from these 187 fully evaluable patients with detectable post-treatment ASNase activity. The averages of pre-treatment control serum levels for Asn and Gln were 44.8 ± 3.0 μM (mean ± SE) and 363.8 ± 23.9 μM, respectively. There were no statistical differences between the PD effects of ASNase formulations on serum Asn deamination, although the lowest Asn levels averaging 2.6 ± 0.4 μM were obtained on 11–14 days post-PEG-ASNase samples (n=14). Glutamine deamination enhanced Asn depletion, and deamination correlated with ASNase activity. At levels 〉0.4 IU/ml, PEG-ASNase and native ASNase provided 95 ± 8% and 85 ± 26% Gln deamination, respectively (p=0.04). Eleven to 14 days after PEG-ASNase, Gln levels averaged 13 ± 5 μM (n=14). In general, Erwinase provided greater Gln deamination (94 ± 5%, n=19) 2–3 days post administration, than either native or PEG-ASNases at comparable activity levels, which were 70–80% (p

Description: Background. Asn depletion in the serum during ASNase treatment (Tx) causes the death of lymphoblasts that lack ability to synthesize Asn. The Asn serum levels during treatment depend on ASNase activity, the rate of clearance of the enzyme and the input rate of Asn into circulation from the liver and other organs (Imax). We developed a population pharmacokinetic & pharmacodynamic (PK-PD) model in NONMEM to estimate the input rate in the standard risk ALL patients (pts) treated on CCG-1962. Methods. We compared the Asn concentrations during induction determined by HPLC amino acid assay in 24 pts who subsequently relapsed and in all event-free (CCR) pts from CCG-1962 SR ALL study. A best fit population PK-PD model between ASNase and Asn concentrations was developed for each patient to estimate the maximum input rate, Imax, and its additive error correction factor. Six year event-free survival was correlated with Imax or additive error with Kaplan-Meier analyses. Results. Patients received either 2500 IU/m2 PEG-ASNase once or 6000 IU/m2 native ASNase x 9, intramuscularly, during induction. The deaminated Asn serum levels were superimposable in patients randomized to native or PEG-ASNase arm. The mean and SDEV for Imax and the additive error are shown in Table 1 for each enzyme preparation for patients in CCR and for those who later developed BM, CNS, or testicular relapses. Imax was significantly greater in the relapsed than in the CCR patients, in the PEG-ASNase (p=0.002) and in the native ASNase (p=0.005) arms. Table 1. Imax and additive error of Asn in relapsed and in continuous complete remission (CCR) patients - CCG-1962 CCG-1962 Arms PEG-ASNase arm, n=56 PEG-ASNase arm, n=56 Native ASNase arm, n=57 Native ASNase arm, n=57 * nmoles/ml/min, ** All values are mean ± SDEV PD Parameters Imax* Additive error* Imax* Additive error* CCR patients 9.93 E -6 ± 2.4 E -5** 1.51 E -6 ± 2.86 E -6 2.92 E -5 ± 1.52 E -4 2.52 E -6 ± 6.61 E -6 N 46 46 43 43 Relapsed 8.9 E -3 ± 6.0 E -3 2.87 E -6 ± 3.1 E -6 4.51 E -3 ± 4.94 E -3 1.05 E -5 ± 1.76 E -5 N 10 10 14 14 p, unequal variance t-test P=0.0021 p=0.25 p=0.0047 p=0.118 Table 2 shows the summary of the Kaplan-Meier analyses in all patients. Both the Imax and additive factor significantly correlate with relapse. Table 2. Summary of Kaplan - Meier analyses Patients PEG-ASNase arm, n=56 PEG-ASNase arm, n=56 Native E.Coli-ASNase arm, n=57 Native E.Coli-ASNase arm, n=57 Parameter and cutoff Imax 〈 0.001 Imax 〉 0.001 Imax 〈 0.001 Imax 〉 0.001 Events, Observed/Exp 2/8.59 8/1.41 3/6.14 11/7.86 Total 45 11 26 31 Log-rank p value 1.64 E -6 0.046 Parameter and cutoff Add rate 〈 1E -6 Add rate 〉 1E -6 Add rate 〈 1E -6 Add rate 〉 1E -6 Events, Observed/Exp 1/5.63 9/4.37 5/10.36 9/3.64 Total 28 28 39 18 Log-rank P value 0.002 0.0024 Conclusions. The Asn levels after Tx are similar in both arms in pts with events and CCR. Nevertheless this PD model strongly suggests that the Imax of input of Asn in the circulation is faster in relapsed than in CCR patients. Furthermore, Imax and its additive rate are correlated with 6 year event free survival of SR ALL pts, independent of the ASNase formulation used in their Tx.

Description: Abstract 3077 Poster Board III-14 Asparaginase is an essential component of combination therapy for ALL and is derived from either Escherichia coli (Native ASNase) or Erwinia chrysanthemi (Erwinia ASNase). Allergic reaction is the most common toxicity of ASNase therapy. Some studies have shown no adverse impact of allergy to native ASNase on outcome. However, compared with native ASNase, in equal doses (“unit for unit” substitution), Erwinia ASNase has been associated with less toxicity and inferior survival in two large multi-institutional cooperative group trials. Pegylated Escherichia coli asparaginase (PEG) has a longer half-life compared to native ASNase and is presumed to be less immunogenic with equivalent efficacy at an appropriate dose and schedule. Between November 1996 and May 2002, 2057 eligible patients with newly diagnosed high-risk ALL were enrolled on Children's Oncology Group study, CCG-1961, and treated with a standard four-drug induction that included native ASNase. Rapid early responders (RER) randomized to stronger post-induction intensification (arms C &D) and all slow early responders (SER) were assigned 6 or 10 doses of PEG (2500 IU/m2/dose) post-induction (n=1157). Patients received native ASNase if PEG was not available. Those with adverse reactions to PEG received Erwinia ASNase (10,000 IU/m2 qod x 6 during consolidation and delayed intensification and 25000 IU/m2 during interim maintenance per single dose of PEG). Antibody titers were collected on a subset of patients pre-consolidation and through all phases. Reaction incidence and event-free survival (EFS) in patients who received PEG versus Erwinia ASNase and in patients with negative versus positive antibody titer were compared among patients assigned to PEG containing regimens. Likelihood of allergic reactions was similar with PEG, native ASNase, and Erwinia during all phases with the exception of Interim Maintenance 1 (IM1). Reactions were less likely with Erwinia (n=235) than with Native ASNase (n=87; odds ratio [OR] = 0.23, p

Description: 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.

Description: Introduction Cure rates of pediatric acute lymphoblastic leukemia (ALL) have markedly improved to approximately 80%, while in adult ALL the rates remain 40-50%. Pediatric ALL regimens contain higher doses of non-myelosuppressive chemotherapy, e.g., vincristine, corticosteroids, and, particularly, higher cumulative doses of asparaginase. Asparaginase use in adults was previously limited due to toxicity concerns. However, several recent studies, using pediatric regimens in adults, contain higher cumulative doses of asparaginase and are showing promising preliminary results. In these studies it was also noted that the long-acting pegaspargase (PEG-ASN) was much more commonly associated with hepatotoxicity in adults than in children. Although hepatotoxicity appears to be the commonest adverse effect of PEG-ASN in adults, it has not been well defined. We report the frequency and characteristics of PEG-ASN-related high-grade hepatotoxicity after multiple doses in adults treated by a pediatric regimen. Methods Between July 2004 and July 2009, 51 adults aged 18 to 57 years were enrolled on a phase II trial with a pediatric ALL regimen that included six planned PEG-ASN doses. PEG-ASN-related toxicities were carefully monitored on a weekly basis after each dose and reported using NCI CTCAE v3.0 for 185 doses delivered. The PEG-ASN dosing schedule was: two doses in induction phases I and II, and four during post-induction cycles (ASH Abstract 1495, 2012). Each PEG-ASN dose was 2000 IU/m2/dose IV, given at intervals of four weeks or greater. Pegaspargase was not discontinued and subsequent doses were not reduced after hepatotoxicity. Results A total of 192 pegaspargase doses were delivered (3.8 doses/patient), with 23 patients receiving all six doses. Of the 28 patients who received fewer than six doses, only 10 (20%) discontinued due non-hepatic toxicity (pancreatitis, allergy, and DVT). Eight (16%) patients discontinued due to allogeneic HSCT while in CR1, while nine (18%) discontinued for other reasons (death post-induction, induction failure, and relapse). Grade 3/4 hyperbilirubinemia occurred in 16 patients (31%) and in 23 doses (12%); grade 3/4 transaminitis occurred in 33 patients (65%) and in 62 doses (34%). Patients with grade 3/4 hyperbilirubinemia tended to be older than those without hepatotoxicity (median age 39 vs 31 years), but all other baseline characteristics were similar. Results of different parameters related to high-grade liver toxicity are detailed in Table 1. Patients with grade 3/4 hyperbilirubinemia and transaminitis received a mean of 4.0 and 4.3 PEG-ASN doses, while the mean number of PEG-ASN doses causing hyperbilirubinemia and transaminitis was only 1.4 and 1.9 doses per patient, respectively. Those without hepatotoxicity received 2.8 PEG-ASN doses per patient. Induction I had the highest incidence (20% of doses delivered) of grade 3/4 hyperbilirubinemia. High-grade transaminitis was spread more evenly among cycles. Grade 3/4 hepatotoxicity was long, with a median duration of 34 days to return to grade 1 for bilirubin and 38 days to return to grade 2 for transaminitis. Of the 16 patients with grade 3/4 hyperbilirubinemia, five did not receive a subsequent PEG-ASN dose for other reasons; of the 11 other patients who received subsequent doses, five (45%) did not re-experience the same toxicity. Of the 33 patients with grade 3/4 transaminitis, eight did not receive a subsequent PEG-ASN dose due to other reasons; of the 25 other patients who received subsequent doses, 10 (40%) did not have this toxicity recur. Summary Our study shows in adults with ALL treated with multiple doses of PEG-ASN that: (1) high-grade hepatoxicity (grade 3/4 hyperbilirubinemia and transaminitis) is a common adverse effect of PEG-ASN; (2) recovery from hepatotoxicity is often long and can delay subsequent chemotherapy; (3) high-grade hepatotoxicity did not necessarily recur after subsequent doses and did not lead to PEG-ASN discontinuation; (4) the dose and schedule of other hepatically cleared or hepatotoxic drugs should be adjusted during periods of PEG-ASN-related hepatotoxicity. In conclusion, although PEG-ASN at this dose and interval is associated in adults with a high rate of hepatotoxicity, it is tolerable and can be given again despite earlier PEG-ASN-related hepatotoxicity. Disclosures: Douer: Sigma Tau Pharmaceuticals : Research Funding.

Description: Obesity has been associated with increased risk of development and poor outcome from a variety of hematological malignancies. There is a lack of consensus as to how to dose chemotherapies in obese patients, and therefore inadequate dosing represents a potential factor contributing to poor outcome. We have previously shown that diet-induced obese mice transplanted with p190BCR/ABL ALL cells and then treated with vincristine (VCR) proportional to body weight (15 mg/kg/wk × 4 wks) have a poorer outcome than non-obese mice (event free survival: Obese = 0.42, Control = 0.75, p=0.07, log rank). The present study was designed to quantify the pharmacokinetic (PK) parameters of vincristine in control and obese mice and determine whether differences in these parameters could explain the poorer outcome in the obese mice. Twenty obese and 20 control mice received tail-vein injections of tritiated vincristine (specific activity 75 mCi/mg; dose 0.5 mg/kg). Blood samples were taken at 5 minutes, and the mice sacrificed at various time-points between 15 minutes and 24 hours post-injection. Whole blood and tissue specimens were solubilized, decolorized, and read on a scintillation counter. Blood vincristine concentrations were fit to a 3-compartment model using the two-stage PK in 3 subsets of VCR concentrations vs. time method. Non-compartmental modeling was used to confirm the results. Due to body weight differences, obese mice received ~ 28% more vincristine per injection than controls. Blood vincristine concentrations in both groups of animals followed a triexponential decay, as has been previously described. Blood levels tended to be higher (by 20±15%) in the obese mice at all time-points tested. While the t1/2α was longer in the obese mice (10.6 vs. 6.0 minutes), the t1/2b and t1/2γ were both shorter (22.7 vs. 27.1 minutes and 114.4 vs. 345.8 hours). Therefore the AUC0 → 24 was higher in the obese mice (3,279 vs. 2,776 ng/ml*hr), while the AUC0 → ∞ was lower in the obese mice (21,705 vs. 53,581 ng/ml*hr). Vincristine concentrations in spleen and bone marrow were similar at all time-points in the obese and control groups. In summary, obesity caused alterations in vincristine pharmacokinetics, characterized by longer initial half-life but shorter terminal half-lives. Thus, it is possible that the decreased AUC0 → ∞ contributed to the poorer outcome in this model. Despite this, blood and tissue concentrations of vincristine were equal or higher in the obese mice during the first 24 hours after injection of the drug when it was dosed proportional to body weight. These data suggest that dosing vincristine in obese patients based on body surface may lead to lower levels in blood and tissue, particularly if the dose is capped. As the prevalence of obesity continues to increase, pharmacokinetics studies should be performed in obese and lean subjects to further optimize chemotherapy dosing regimens in obese patients.

Description: Background: ASNase is a critical treatment component in childhood acute lymphoblastic leukemia (ALL). As ASNase is a bacterial protein, production of anti-ASNase Ab, often associated with clinical allergy, poses a frequent problem during ASNase therapy. Sixty percent of higher risk ALL patients, who received native ASNase in induction, were Ab(+) by 5 months into therapy (Panosyan et al., 2004). Moreover, 22%–29% of these patients had no clinical allergy (silent hypersensitivity) and were at increased risk for relapse. Patients and Methods: Physicians from 13 institutions submitted samples for 48 children in first remission, aged 14 to 252 months, on various SR or HR ALL protocols with suspected ASNase allergy. The male/female ratio was 1.4. The serum samples were assessed for ASNase activity and anti-ASNase Ab as reported earlier (Avramis, et al., Blood 2002). Ab titer is expressed as the numeric ratio relative to an Ab negative control. Results: Allergic symptoms ranged from localized skin rash and swelling to respiratory difficulties and/or anaphylaxis. Neutralizing anti-PEG-ASNase Ab’s were seen in 41 patients (85%). The results were examined with respect to age, gender, ASNase formulation received, time of post-ASNase administration, and the physician’s clinical observations. Higher Ab ratios 〉 1.1 correlated with low or no ASNase activity post-PEG-ASNase (46/48 patients) or post-Native ASNase dosing (2 patients). Fourteen patients had cutaneous manifestations (rash, hives, urticaria). All had neutralizing Ab and no enzymatic activity. Nine had higher Ab ratios and 5 had lower Ab ratios. Eight additional patients had localized or generalized swelling; all had higher Ab ratios. Similarly, over the entire CCG-1961 study, 526/1100 patients had a clinical reaction; 476/526 had higher Ab ratios (90%). Conclusions: We found neutralizing Ab in 85% of patients with apparent clinical ASNase allergy. Neutralizing Ab was correlated with lower or absent ASNase activity. Lower Ab ratios may be associated with earlier time points in the anamnestic response. In the remaining 15% of patients with an apparent clinical reaction, we found no Ab and substantial ASNase activity. Monitoring ASNase activity and Ab may be useful for guiding ASNase therapy. Patients with no Ab and substantial activity, might be rechallenged with the same product despite an apparent allergic reaction.