Larry J. Schaaf

Irinotecan Therapy in Adults With Recurrent or Progressive Malignant Glioma

PURPOSE To determine the activity, toxicity, and pharmacokinetics of irinotecan (CPT-11, Camptosar; Pharmacia & Upjohn, Kalamazoo, MI) in the treatment of adults with progressive, persistent, or recurrent malignant glioma. PATIENTS AND METHODS Patients with progressive or recurrent malignant gliomas were enrolled onto this study between October 1996 and August 1997. CPT-11 was given as a 90-minute intravenous (i.v.) infusion at a dose of 125 mg/m2 once weekly for 4 weeks followed by a 2-week rest, which comprised one course. Plasma concentrations of CPT-11 and its metabolites, SN-38 and SN-38 glucuronide (SN-38G), were determined in a subset of patients. RESULTS All 60 patients who enrolled (36 males and 24 females) were treated with CPT-11 and all were assessable for toxicity, response, and survival. Pharmacokinetic data were available in 32 patients. Nine patients (15%; 95% confidence interval, 6% to 24%) had a confirmed partial response, and 33 patients (55%) achieved stable disease lasting more than two courses (12 weeks). Toxicity observed during the study was limited to infrequent neutropenia, nausea, vomiting, and diarrhea. CPT-11, SN-38, and SN-38G area under the plasma concentration-time curves through infinite time values in these patients were approximately 40%, 25%, and 25%, respectively, of those determined previously in patients with metastatic colorectal cancer not receiving antiepileptics or chronic dexamethasone treatment. CONCLUSION Response results document that CPT-11, given with a standard starting dose and treatment schedule, has activity in patients with recurrent malignant glioma. However, the low incidence of severe toxicity and low plasma concentrations of CPT-11 and SN-38 achieved in this patient population suggest that concurrent treatment with anticonvulsants and dexamethasone enhances drug clearance.

Clinical response and miR-29b predictive significance in older AML patients treated with a 10-day schedule of decitabine

A phase II clinical trial with single-agent decitabine was conducted in older patients (≥60 years) with previously untreated acute myeloid leukemia (AML) who were not candidates for or who refused intensive chemotherapy. Subjects received low-dose decitabine at 20 mg/m2 i.v. over 1 h on days 1 to 10. Fifty-three subjects enrolled with a median age of 74 years (range, 60–85). Nineteen (36%) had antecedent hematologic disorder or therapy-related AML; 16 had complex karyotypes (≥3 abnormalities). The complete remission rate was 47% (n = 25), achieved after a median of three cycles of therapy. Nine additional subjects had no morphologic evidence of disease with incomplete count recovery, for an overall response rate of 64% (n = 34). Complete remission was achieved in 52% of subjects presenting with normal karyotype and in 50% of those with complex karyotypes. Median overall and disease-free survival durations were 55 and 46 weeks, respectively. Death within 30 days of initiation of treatment occurred in one subject (2%), death within 8 weeks in 15% of subjects. Given the DNA hypomethylating effect of decitabine, we examined the relationship of clinical response and pretreatment level of miR-29b, previously shown to target DNA methyltransferases. Higher levels of miR-29b were associated with clinical response (P = 0.02). In conclusion, this schedule of decitabine was highly active and well tolerated in this poor-risk cohort of older AML patients. Levels of miR-29b should be validated as a predictive factor for stratification of older AML patients to decitabine treatment.

Phase II Study of Flavopiridol in Relapsed Chronic Lymphocytic Leukemia Demonstrating High Response Rates in Genetically High-Risk Disease

PURPOSE Patients with chronic lymphocytic leukemia (CLL) with high-risk genomic features achieve poor outcomes with traditional therapies. A phase I study of a pharmacokinetically derived schedule of flavopiridol suggested promising activity in CLL, irrespective of high-risk features. Given the relevance of these findings to treating genetically high-risk CLL, a prospective confirmatory study was initiated. PATIENTS AND METHODS Patients with relapsed CLL were treated with single-agent flavopiridol, with subsequent addition of dexamethasone to suppress cytokine release syndrome (CRS). High-risk genomic features were prospectively assessed for response to therapy. RESULTS Sixty-four patients were enrolled. Median age was 60 years, median number of prior therapies was four, and all patients had received prior purine analog therapy. If patients tolerated treatment during week 1, dose escalation occurred during week 2. Dose escalation did not occur in four patients, as a result of severe tumor lysis syndrome; three of these patients required hemodialysis. Thirty-four patients (53%) achieved response, including 30 partial responses (PRs; 47%), three nodular PRs (5%), and one complete response (1.6%). A majority of high-risk patients responded; 12 (57%) of 21 patients with del(17p13.1) and 14 (50%) of 28 patients with del(11q22.3) responded irrespective of lymph node size. Median progression-free survival among responders was 10 to 12 months across all cytogenetic risk groups. Reducing the number of weekly treatments per cycle from four to three and adding prophylactic dexamethasone, which abrogated interleukin-6 release and CRS (P < or = .01), resulted in improved tolerability and treatment delivery. CONCLUSION Flavopiridol achieves significant clinical activity in patients with relapsed CLL, including those with high-risk genomic features and bulky lymphadenopathy. Subsequent clinical trials should use the amended treatment schedule developed herein and prophylactic corticosteroids.

Clinical response and pharmacokinetics from a phase 1 study of an active dosing schedule of flavopiridol in relapsed chronic lymphocytic leukemia

We previously reported interim results of a phase 1 trial in patients with chronic lymphocytic leukemia (CLL) whereby flavopiridol was administered intravenously as a 30-minute bolus followed by 4-hour infusion. We now report full pharmacokinetic (PK) data, correlations of PK with clinical outcomes, and final response and progression-free survival (PFS). Twenty-one (40%) of 52 patients with relapsed CLL achieved a partial response (PR) with a median PFS of 12 months. Responders included 17 (40%) of 43 fludarabine refractory patients, 7 (39%) of 18 patients with del(17p13), and 14 (74%) of 19 patients with del(11q22). Six responders received repeat therapy at relapse, and 5 responded again with a second median PFS of 10 months. Noncompartmental analysis and nonlinear mixed effects modeling was used to estimate PK parameters and evaluate covariates. Two-compartment population parameter estimates were 31.4 L/h, 65.8 L, 8.49 L/h, and 157 L for CL, V1, Q, and V2, respectively. Flavopiridol area under the plasma concentration-time curve (AUC) correlated with clinical response and cytokine release syndrome, and glucuronide metabolite AUC correlated with tumor lysis syndrome. These composite results confirm high activity of this pharmacokinetically derived schedule in relapsed, genetically high-risk CLL. Furthermore, PK describes some, but not all, variability in response and toxicity.

Assessment of Tumor Necrosis Factor Alpha Blockade As an Intervention to Improve Tolerability of Dose-Intensive Chemotherapy in Cancer Patients

PURPOSE Maintaining dose-intensity with chemotherapeutic agents is hindered by a number of adverse effects including asthenia/fatigue. Tumor necrosis factor (TNF) is one of the cytokines responsible for the fatigue and cachexia associated with malignancies. We used etanercept (TNF-decoy receptor) to maintain dose-intensity of weekly docetaxel. PATIENTS AND METHODS Initially, 12 patients with advanced malignancies were randomly assigned to either docetaxel 43 mg/m2 weekly alone (cohort A) or the same docetaxel dose plus etanercept 25 mg subcutaneously twice weekly (cohort B). Subsequently, higher doses of docetaxel in combination with etanercept were evaluated. Pharmacokinetics (PKs), nuclear factor-kappa B (NF-kappaB) activation, and intracellular cytokines levels were measured. Patients completed weekly questionnaires quantifying asthenia/fatigue. RESULTS Twenty-nine of 36 intended docetaxel doses during the first cycle were delivered in cohort A, and 35 of 36 doses were delivered in cohort B (P = .055). Three cohort B patients received additional cycles in the absence of disease progression or severe toxicity, whereas no patients from cohort A received additional cycles. Escalation to docetaxel 52 mg/m2 weekly with etanercept resulted in neutropenia, not fatigue, as the limiting adverse effect, and the addition of filgrastim permitted the maintenance of dose-intensity in additional patients. Patients randomly selected to receive etanercept/docetaxel self-reported less fatigue (P < .001), and docetaxel PKs show no relevant influence of etanercept. NF-kappaB activation and increased expression of TNF-alpha were associated with increments in docetaxel dose. Antitumor activity was noticed exclusively in patients receiving etanercept. CONCLUSION The addition of etanercept is safe and had no impact on docetaxel concentrations. The significant improvement in tolerability and the trend toward preservation of dose-intensity suggests further exploration of TNF blockade as an adjunct to cancer therapies.

Phase I and Pharmacokinetic Trial of Oral Irinotecan Administered Daily for 5 Days Every 3 Weeks in Patients With Solid Tumors

PURPOSE We conducted a phase I dose-escalation trial of orally administered irinotecan (CPT-11) to characterize the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), pharmacokinetic profile, and antitumor effects in patients with refractory malignancies. PATIENTS AND METHODS CPT-11 solution for intravenous (IV) use was mixed with CranGrape juice (Ocean Spray, Lakeville-Middleboro, MA) and administered orally once per day for 5 days every 3 weeks to 28 patients. Starting dosages ranged from 20 to 100 mg/m2/d. RESULTS Grade 4 delayed diarrhea was the DLT at the 80 mg/m2/d dosage in patients younger than 65 years of age and at the 66 mg/m2/d dosage in patients 65 or older. The other most clinically significant toxicity of oral CPT-11 was neutropenia. A linear relationship was found between dose, peak plasma concentration, and area under the concentration-time curve (AUC) for both CPT-11 and SN-38 lactone, implying no saturation in the conversion of irinotecan to SN-38. The mean metabolic ratio ([AUC(SN-38 total) + AUC(SN-38G total)]/AUC(CPT-11 total)) was 0.7 to 0.8, which suggests that oral dosing results in presystemic conversion of CPT-11 to SN-38. An average of 72% of SN-38 was maintained in the lactone form during the first 24 hours after drug administration. One patient with previously treated colorectal cancer and liver metastases who received oral CPT-11 at the 80 mg/m2/d dosage achieved a confirmed partial response. CONCLUSION The MTD and recommended phase II dosage for oral CPT-11 is 66 mg/m2/d in patients younger than 65 years of age and 50 mg/m2/d in patients 65 or older, administered daily for 5 days every 3 weeks. The DLT of diarrhea is similar to that observed with IV administration of CPT-11. The biologic activity and favorable pharmacokinetic characteristics make oral administration of CPT-11 an attractive option for further clinical development.

Phase II Study of Irinotecan Plus Cisplatin in Patients With Advanced Non–Small-Cell Lung Cancer

PURPOSE To evaluate the antitumor efficacy and safety of a combination of irinotecan (CPT-11) and cisplatin in patients with inoperable non-small-cell lung cancer (NSCLC). A secondary objective was to characterize the pharmacokinetics and pharmacodynamics of CPT-11 and its active metabolite, SN-38. PATIENTS AND METHODS Patients with stage IIIB or IV NSCLC were treated with repeated 4-week courses comprising CPT-11 (60 mg/m(2)) administered on days 1, 8, and 15, and a single dose of cisplatin (80 mg/m(2)) after CPT-11 administration on day 1. RESULTS Fifty-two patients were enrolled, including 33 men and 19 women. The median age was 61 years (range, 29 to 79 years). Southwest Oncology Group performance status was 0 in 12 patients, 1 in 32 patients, and 2 in eight patients. Eleven and 41 patients had stage IIIB and IV disease, respectively. Objective responses occurred in 28.8% of patients (15 of 52; 95% confidence interval, 16.5% to 41.2%). The median survival duration was 9.9 months (range, 1.6 to 30.8 months). The 1-year survival rate was 37%. Grade 3/4 adverse events consisted primarily of nausea (32. 7% ) or vomiting (13.5%), late-onset diarrhea (17.3%), and neutropenia (46.1%). The study design led to preferential modification of CPT-11 doses, resulting in CPT-11 dose attenuations to < or = 40 mg/m(2) in the majority of patients (31 of 52; 60%), whereas dose reductions of cisplatin were uncommon. CPT-11 pharmacokinetic parameters were comparable to those reported previously in single-agent studies. CONCLUSION CPT-11/cisplatin is an active combination regimen with manageable toxicity in the therapy of stage IIIB/IV NSCLC. Future studies should be designed with schedules and dose modification provisions that avoid unnecessary CPT-11 dose reductions to exploit more directly the therapeutic synergy of these agents.

Flavopiridol, Fludarabine, and Rituximab in Mantle Cell Lymphoma and Indolent B-Cell Lymphoproliferative Disorders

PURPOSE Flavopiridol downmodulates antiapoptotic proteins associated with resistance to fludarabine and rituximab and is effective against p53-mutated chronic lymphocytic leukemia (CLL). We conducted a phase I study of flavopiridol, fludarabine, and rituximab (FFR) in patients with mantle-cell lymphoma (MCL), indolent B-cell non-Hodgkins lymphomas (B-NHL), and CLL to determine the activity of FFR. PATIENTS AND METHODS Therapy included fludarabine 25 mg/m(2) intravenously (IV) days 1 to 5 and rituximab 375 mg/m(2) day 1 every 28 days for 6 cycles. We administered flavopiridol 50 mg/m(2) by 1-hour IV bolus (IVB) day 1 (n = 15); day 1 to 2 (n = 6); 20 mg/m(2) 30-minute IVB + 20 mg/m(2) 4-hour IV infusion (n = 3); or 30 mg/m(2) + 30 mg/m(2) (n = 14). RESULTS Thirty-eight patients (median age, 62 years) with MCL (n = 10); indolent B-NHL including follicular (n = 9), marginal zone (n = 4), lymphoplasmacytic (n = 1), or small lymphocytic lymphoma (n = 3); and CLL (n = 11), were enrolled. Twenty-two patients were previously untreated; 16 had received one to two prior therapies. Two patients in cohort 2 developed grade 3 dose-limiting toxicity (seizures, renal insufficiency). The median number of treatment cycles was 4, with cytopenias (n = 10) and fatigue (n = 3) the most common reasons for early discontinuation. Overall response rate was 82% (complete response, 50%; unconfirmed complete response, 5%; partial response, 26%), including 80% of patients with MCL (median age, 68; seven complete responses, one partial response). Median progression-free survival (PFS) was 25.6 months. Median PFS of patients with nonblastoid variant MCL (n = 8) was 35.9 months. CONCLUSION FFR was active in MCL, indolent B-NHL, and CLL and should be studied for older patients with MCL who are not candidates for aggressive chemotherapy.

Dose Escalation of Lenalidomide in Relapsed or Refractory Acute Leukemias

PURPOSE Lenalidomide is effective in myeloma and low-risk myelodysplastic syndromes with deletion 5q. We report results of a phase I dose-escalation trial of lenalidomide in relapsed or refractory acute leukemia. PATIENTS AND METHODS Thirty-one adults with acute myeloid leukemia (AML) and four adults with acute lymphoblastic leukemia (ALL) were enrolled. Lenalidomide was given orally at escalating doses of 25 to 75 mg daily on days 1 through 21 of 28-day cycles to determine the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD), as well as to provide pharmacokinetic and preliminary efficacy data. RESULTS Patients had a median age of 63 years (range, 22 to 79 years) and a median of two prior therapies (range, one to four therapies). The DLT was fatigue; 50 mg/d was the MTD. Infectious complications were frequent. Plasma lenalidomide concentration increased proportionally with dose. In AML, five (16%) of 31 patients achieved complete remission (CR); three of three patients with cytogenetic abnormalities achieved cytogenetic CR (none with deletion 5q). Response duration ranged from 5.6 to 14 months. All responses occurred in AML with low presenting WBC count. No patient with ALL responded. Two of four patients who received lenalidomide as initial therapy for AML relapse after allogeneic transplantation achieved durable CR after development of cutaneous graft-versus-host disease, without donor leukocyte infusion. CONCLUSION Lenalidomide was safely escalated to 50 mg daily for 21 days, every 4 weeks, and was active with relatively low toxicity in patients with relapsed/refractory AML. Remissions achieved after transplantation suggest a possible immunomodulatory effect of lenalidomide, and results provide enthusiasm for further studies in AML, either alone or in combination with conventional agents or other immunotherapies.

Phase I Trial of Lenalidomide and CCI-779 in Patients With Relapsed Multiple Myeloma: Evidence for Lenalidomide–CCI-779 Interaction via P-Glycoprotein

PURPOSE Multiple myeloma (MM) is an incurable plasma-cell neoplasm for which most treatments involve a therapeutic agent combined with dexamethasone. The preclinical combination of lenalidomide with the mTOR inhibitor CCI-779 has displayed synergy in vitro and represents a novel combination in MM. PATIENTS AND METHODS A phase I clinical trial was initiated for patients with relapsed myeloma with administration of oral lenalidomide on days 1 to 21 and CCI-779 intravenously once per week during a 28-day cycle. Pharmacokinetic data for both agents were obtained, and in vitro transport and uptake studies were conducted to evaluate potential drug-drug interactions. RESULTS Twenty-one patients were treated with 15 to 25 mg lenalidomide and 15 to 20 mg CCI-779. The maximum-tolerated dose (MTD) was determined to be 25 mg lenalidomide with 15 mg CCI-779. Pharmacokinetic analysis indicated increased doses of CCI-779 resulted in statistically significant changes in clearance, maximum concentrations, and areas under the concentration-time curves, with constant doses of lenalidomide. Similar and significant changes for CCI-779 pharmacokinetics were also observed with increased lenalidomide doses. Detailed mechanistic interrogation of this pharmacokinetic interaction demonstrated that lenalidomide was an ABCB1 (P-glycoprotein [P-gp]) substrate. CONCLUSION The MTD of this combination regimen was 25 mg lenalidomide with 15 mg CCI-779, with toxicities of fatigue, neutropenia, and electrolyte wasting. Pharmacokinetic and clinical interactions between lenalidomide and CCI-779 seemed to occur, with in vitro data indicating lenalidomide was an ABCB1 (P-gp) substrate. To our knowledge, this is the first report of a clinically significant P-gp-based drug-drug interaction with lenalidomide.