Phase III trial of nonpegylated liposomal doxorubicin in combination with trastuzumab and paclitaxel in HER2-positive metastatic breast cancer

BACKGROUND

Nonpegylated liposomal doxorubicin liposomal doxorubicin, (Myocet™; Sopherion Therapeutics, Inc Canada, and Cephalon, Europe) (NPLD; Myocet(®)) in combination with trastuzumabHerceptin(®) (Hoffmann-La Roche) has shown promising activity and cardiac safety. We conducted a randomized phase III trial of first-line NPLD plus trastuzumab and paclitaxel (Pharmachemie B.V.) (MTP) versus trastuzumab plus paclitaxel (TP) in patients with human epidermal growth factor 2 receptor (HER2)-positive metastatic breast cancer.

PATIENTS AND METHODS

Patients were randomly assigned to NPLD (M, 50 mg/m(2) every 3 weeks for six cycles), trastuzumab (T, 4 mg/kg loading dose followed by 2 mg/kg weekly), and paclitaxel (P, 80 mg/m(2) weekly) or T + P at the same doses until progression or toxicity. The primary efficacy outcome was progression-free survival (PFS).

RESULTS

One hundred and eighty-one patients were allocated to receive MTP, and 183 to TP. Median PFS was 16.1 and 14.5 months with MTP and TP, respectively [hazard ratio (HR) 0.84; two-sided P = 0.174]. In patients with estrogen receptor (ER)- and progesterone receptor (PR)-negative tumors, PFS was 20.7 and 14.0 months, respectively [HR 0.68; 95% confidence interval (CI) 0.47-0.99]. Median overall survival (OS) was 33.6 and 28.9 months with MTP and TP, respectively (HR 0.79; two-sided P = 0.083). In ER- and PR-negative tumors, OS was 38.2 and 27.9 months, respectively (HR 0.63; 95% CI 0.42-0.93). The frequency of adverse events was higher with MTP, but there was no significant difference in cardiac toxicity between treatment arms.

CONCLUSION(S)

The trial failed to demonstrate a significant clinical improvement with the addition of M to TP regimen. The clinical benefit observed in an exploratory analysis in the ER- and PR-negative population deserves consideration for further clinical trials.

CLINICAL TRIAL NUMBER

NCT00294996.

Abstract P6-14-02: A Phase 3 Randomized, Controlled Trial of Myocet, Trastuzumab and Paclitaxel vs. Trastuzumab and Paclitaxel for 1st Line Therapy of HER2+ Metastatic Breast Cancer

Background: Myocet™ (M) is a non-pegylated liposomal doxorubicin which exhibits reduced cardiotoxicity as compared to conventional doxorubicin. A phase 1/2 non-randomized multi-site trial combining M, trastuzumab (H) and paclitaxel (T) has resulted in high response rate, prolonged time to progression and improved overall survival, with no clinical cardiac toxicity in patients (pts) with first line metastatic breast cancer (MBC) over-expressing human epidermal growth factor-2neu (HER2+) (Cortes et al Clin Cancer res 2009:15:307).

Methods: This multicenter study was designed to demonstrate the efficacy and cardiac safety of M+ H + T vs. the standard of care, H + T, in pts with HER2+ MBC with no prior chemotherapy for MBC. After stratification by hormone receptor status, prior or no prior anthracycline (A) therapy, age ≥50 or >50 y and geography, patients were randomly allocated to receive either M (50 mg/m2 q 3 wks for 6 cycles), H (4 mg/kg loading dose followed by 2 mg/kg q wk) and T (80 mg/m2 q wk) or H + T until progression or toxicity. The primary efficacy outcome is progression-free survival (PFS), as determined by a blinded independent review committee (IRC). The primary safety outcome is the incidence of NYHA class 3 or 4 heart failure or cardiac death, independently adjudicated. Secondary endpoints are overall survival and tumor response, also determined by the IRC according to RECIST. 332 pts were needed to detect a 30% difference in PFS with 80% power.

Results: Between 2006 and 2009, 363 HER2+ women from 12 countries were enrolled. Median age is 53 yr (range 22-79); 80% are Caucasian; with ECOG performance status of 0 (62%) and 1 (38%); 42% are ER and/or PR positive; 40% received adjuvant chemotherapy, 24% hormone therapy, and 37% radiotherapy; 33% received prior A, median lifetime cumulativedoxorubicin and epirubicin dose (range) were 240 (45-360) mg/m2 and 360 (69-600) mg/m2, respectively. The final analysis of PFS is scheduled for 3Q10.

Conclusions: The safety and efficacy data will be presented at the meeting. Clinical Trials.Gov Identifier: NCT00294996

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-14-02.

EGFr expression and clinical outcome in head and neck cancer patients treated with radiotherapy with or without cetuximab

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Background: Increased expression of epidermal growth factor receptor (EGFr) has been correlated with poor outcome for patients with squamous cell carcinoma of the head and neck (SCCHN). This analysis was performed to examine the prognostic significance of EGFr expression in patients with locoregionally advanced SCCHN treated with radiotherapy (R) with or without cetuximab (C, an IgG1 anti-EGFr monoclonal antibody). Methods: This correlative study was performed on tumor biopsy samples from patients with locoregionally advanced SCCHN who were randomized to R with or without C as previously described (ASTRO Abstract #120, 2005). Immunohistochemistry was utilized to assess the percentage of tumor cells that stained for EGFr (JCO 23:5568, 2005). Kaplan-Meier estimates of locoregional control and survival were derived, and Cox regression was used to adjust for differences in prognostic factors. Results: Tumor specimens were evaluated from 339 of the 424 randomized patients. The median percentage of EGFR-detectable tumor cells (EDTC) was 50%. 183 patients had ≤50% EDTC, whereas 156 patients had >50% EDTC. The addition of C to R resulted in improved locoregional control (LRC, p = 0.005) and survival (p = 0.03) in the overall study. The LRC and survival results are summarized for patients with ≤50% EDTC and patients with >50% EDTC. Medians are measured in months. These findings were not altered after adjusting for imbalances in known prognostic factors of Karnofsky score (90–100 vs. 60–80) and primary site (Oropharynx or Larynx vs. Hypopharynx). Conclusions: A high positive EGFr expression in SCCHN, as determined by current methodology, is not necessary for response to radiotherapy and cetuximab. These results warrant further evaluation.

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Phase III trial of liposomal doxorubicin and cyclophosphamide compared with epirubicin and cyclophosphamide as first-line therapy for metastatic breast cancer

OBJECTIVE

To ascertain the efficacy and tolerability of non-pegylated liposomal doxorubicin (Myocet) and epirubicin combined with cyclophosphamide in the first-line treatment of patients with metastatic breast cancer.

METHODS

One hundred and sixty anthracycline-naïve metastatic breast cancer patients were randomised to receive Myocet (M; 75 mg/m(2)) or epirubicin (E; 75 mg/m(2)) in combination with cyclophosphamide (C; 600 mg/m(2)), every 3 weeks for up to eight cycles.

OUTCOME MEASURES

Response (overall response = complete + partial response rates), time to disease progression, overall survival and cardiac function (left ventricular ejection fraction).

RESULTS

Overall response rates were 46% and 39% for MC and EC treatment, respectively (P=0.42). MC was superior to EC with respect to median time to treatment failure (5.7 versus 4.4 months; P=0.01) and median time to disease progression (7.7 versus 5.6 months; P=0.02). Median survival times were 18.3 and 16.0 months for MC and EC, respectively (P=0.504). Unsurprisingly, given an equimolar comparison, neutropenia and stomatitis/mucositis were significantly more common in patients who received MC. However, there was less injection site toxicity with MC. Both treatments showed a low incidence of cardiotoxicity.

CONCLUSION

Myocet appears to be an acceptable alternative to epirubicin as a first-line treatment for patients with metastatic breast cancer because it combines the dose-effect reliability of doxorubicin with the level of safety provided by epirubicin.

AIDS-related Kaposi's sarcoma: a phase II study of liposomal doxorubicin. The TLC D-99 Study Group

TLC D-99 is a unique liposomal formulation of doxorubicin that consists of phosphatidyl choline/cholesterol. The objectives of the study were to evaluate safety and efficacy of two doses of TLC D-99 in the treatment of patients with AIDS-related Kaposi's Sarcoma (KS). Forty HIV-infected persons with biopsy-proven KS were randomized to receive TLC D-99 at doses of either 10 (low) or 20 (high) mg/m2 every 2 weeks. Patients assigned to the low-dose arm could be escalated to the high-dose arm if their KS progressed after 3 cycles of therapy. Median age was 35 years (range, 26-47) and median CD4 count was 13 (range, 0-440). Nineteen patients were assigned to receive the low dose, and 21 patients were assigned to the high dose. Partial response occurred in 15% (6 of 40) of the patients or in 5% (1 of 19) and 24% (5 of 21) in the low- and high-dose arms, respectively; stable disease was observed in 65% (26 of 40) or in 68% (13 of 19) and 62% (13 of 21) in the low and high doses, respectively. Neutropenia was the major toxicity and was observed in 68 and 81% of patients with the low- and high-dose arms, respectively; grade 4 neutropenia was observed in 16 and 14%, respectively. Mild alopecia was noted in only 8%. Therefore, TLC D-99 is active against AIDS-related KS, and the response is dose-dependent.

Phase II trial of liposome-encapsulated doxorubicin, cyclophosphamide, and fluorouracil as first-line therapy in patients with metastatic breast cancer

PURPOSE

To determine the efficacy and safety profile, including the risk for cardiac toxicity, of liposome-encapsulated doxorubicin (TLC D-99), fluorouracil (5-FU), and cyclophosphamide as first-line chemotherapy in patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Forty-one women were registered in this phase II study. All patients had measurable disease and no previous chemotherapy for MBC. Treatment consisted of TLC D-99 60 mg/m2 and cyclophosphamide 500 mg/m2 on day 1 and 5-FU 500 mg/m2 on days 1 and 8 every 3 weeks. Serial cardiac monitoring, including endomyocardial biopsies, was performed.

RESULTS

The overall response rate was 73% (95% confidence interval, 57% to 86%). The median duration of response was 11.2 months, the median time to treatment failure was 8.1 months, and the median overall survival duration was 19.4 months. The median number of cycles per patient was 10. The median cumulative dose of TLC D-99 was 528 mg/m2. Ten patients required hospitalization for febrile neutropenia. Nausea/vomiting, stomatitis, and fatigue higher than grade 2 occurred in 12%, 15%, and 41% of patients, respectively. Twenty-one patients reached a cumulative doxorubicin dose greater than 500 mg/m2. Three patients (7%) were withdrawn from the study due to protocol-defined cardiac toxicity, two because of a decrease in left ventricular ejection fraction to < or = 40%, and one because her endomyocardial biopsy result was grade 1.5. One patient had congestive heart failure that was probably nonanthracycline related.

CONCLUSION

This chemotherapy regimen, including TLC D-99, was highly active against MBC and associated with low cardiac toxicity despite high cumulative doses of doxorubicin.

Phase II trial of high-dose liposome-encapsulated doxorubicin with granulocyte colony-stimulating factor in metastatic breast cancer. TLC D-99 Study Group

PURPOSE

To estimate the toxicity and response rate of high-dose liposome-encapsulated doxorubicin (TLC D-99, Evacet, The Liposome Company Inc, Princeton, NJ) in patients with advanced breast cancer.

PATIENTS AND METHODS

Fifty-two breast cancer patients with bidimensionally measurable metastatic disease and no prior chemotherapy for metastatic disease received a 135 mg/m2 intravenous (i.v.) bolus of TLC D-99 with 5 microg/kg of granulocyte colony-stimulating factor via subcutaneous injection every 21 days.

RESULTS

The median number of treatment cycles of TLC D-99 was three (range, one to 10 cycles), and the median total cumulative dose of TLC D-99 was 405 mg/m2 (range, 135 to 1,065 mg/m2). Grade IV neutropenia, thrombocytopenia, and mucositis were experienced by 48 (92%), 46 (88%), and 10 (19%) patients, respectively. Twenty (38%) of patients experienced cardiac toxicity: four (8%) experienced a decrease of 20% or more in left ventricular ejection fraction (LVEF) to a final value > or = 50%, nine (17%) experienced a decrease of 10% or more in LVEF to a final value less than 50%, and seven (13%) developed symptomatic congestive heart failure (CHF), including one patient who died of cardiomyopathy after receiving a total dose of 1,035 mg/m2. In a stepwise logistic regression model, the significant risk factors for the development of CHF were the cumulative dose of prior adjuvant doxorubicin (P = .007) and the total cumulative dose of TLC D-99 (P = .032). The overall response rate was 46% (95% confidence interval [CI], 32% to 61%) on an intent-to-treat basis. The median duration of response was 7.4 months (95% CI, 6.1 to 19.6 months) and the median progression-free survival was 6.1 months (95% CI, 5.4 to 7.5 months).

CONCLUSION

There was no added therapeutic benefit to the dose escalation of TLC D-99 in this study. A high rate of cardiotoxicity was also observed, especially among patients who had received prior adjuvant doxorubicin. This was probably attributable to the dose and schedule of TLC D-99 used in this trial, as well as the patient's lifetime cumulative doxorubicin dose. Administration of high-dose TLC D-99 at 135 mg/m2 every 3 weeks by i.v. bolus infusion does not warrant further investigation.

Multicenter phase II study of brequinar sodium in patients with advanced breast cancer

In this study, 34 patients with advanced breast cancer were treated with brequinar sodium: 75% of the patients were postmenopausal, and 94% had received chemotherapy previously; 50% had previously received an anthracycline-containing regimen. Brequinar was administered intravenously at a median weekly dose of 1,200 mg/m2. The toxicity was moderate, with 17 patients (50%) experiencing grade 3 or 4 toxicity. There were 33 patients evaluable for response: 4 patients (12%; 95% confidence interval, 3.4-28.2%) achieved partial responses, 10 patients (30%) were stable, and 19 patients (58%) had progressive disease. We conclude that, at this dose and schedule, brequinar has only modest activity in patients with advanced breast cancer.

The selective use of AMSA following high-dose cytarabine in patients with acute myeloid leukaemia in relapse: a Leukemia Intergroup study

This clinical trial was designed to evaluate the role of high-dose cytarabine (ara-C) in the treatment of adults with acute myeloid leukaemia (AML) in first relapse. We also tested the hypothesis that the selective use of AMSA (100 mg/m2/d on days 7, 8 and 9) would increase the complete remission (CR) rate when leukaemia cells remained in the bone marrow immediately following 6 d of Ara-C (2-3 g/m2/12 h) alone. Of 155 patients evaluable for response, 115 (74%) experienced marked cytoreduction by day 6 and received no further induction chemotherapy; 53 (45%) of these patients achieved CR after one course and 45 (38%) had resistant disease. The 36 patients (23%) with inadequate cytoreduction after the 6 d of ara-C alone were randomly assigned either to no further chemotherapy (21 patients) or to 3 d of AMSA (15 patients). The CR rates after one course were 14% and 53%, respectively (P = 0.01), and the fractions with resistant disease were 76% and 40%, respectively. The fractional reduction of leukaemia cells in the day 6 bone marrow aspirate specimen (P < 0.0001) and the reduction in the leukaemia cell mass measured in the day 6 marrow biopsy (P = 0.001) were the strongest predictors for achieving CR versus having residual disease in univariate analyses. The median duration of remission was 5 months, but seven patients (10%) remain in CR after 30-92 + months. Among the 140 patients who received only the 6 d of ara-C, the pretreatment albumin (P = 0.002) and lactate dehydrogenase (P = 0.01) levels were the strongest predictors of response in univariate analyses, but only the albumin remained significant (P = 0.01) in a stepwise logistic regression analysis. Those patients with albumin > 4.0 mg/dl and LDH < 125% of normal had a 71% CR rate, and only 16% had resistant disease. Thus, pretreatment characteristics and rapid cytoreductin in the day 6 bone marrow sample identified a favourable subset of patients with AML in first relapse, some of whom responded quite well to 6 d of ara-C alone and have had long disease-free remissions.

Comparison of the Radiation Therapy Oncology Group and American Joint Committee on Cancer staging systems among patients with non-small cell lung cancer receiving hyperfractionated radiation therapy. A report of the Radiation Therapy Oncology Group protocol 83-11

Since 1973, the Radiation Therapy Oncology Group (RTOG) has staged and stratified patients in non-small cell lung cancer (NSCLC) protocols according to the RTOG staging system. In 1985, the American Joint Committee on Cancer (AJCC) revised its lung cancer staging system, with the principle differences from the RTOG system being the staging of involvement of the chest wall and of contralateral mediastinal and hilar lymph nodes. To determine if the AJCC system discriminated outcome differently than the RTOG system in a nonoperative series, all 850 evaluable patients treated with hyperfractionated radiation therapy (RT) on the RTOG protocol 83-11 were restaged by the AJCC system. There was 67% agreement in patient distribution between the following comparable stages in each system: RTOG Stage II/AJCC Stage II; RTOG Stage III/AJCC Stage IIIA; and RTOG Stage IV/AJCC Stage IIIB. Both systems successfully predicted for survival (P less than 0.001), although the RTOG staging was more discriminating (relative risk ratios, 1.59 versus 1.38). Among the 507 favorable patients (those with less than or equal to 5% weight loss and Karnofsky performance status [KPS] of 70 to 100), the RTOG staging was also more predictive (P = 0.004 versus P = 0.01). When RTOG Stage III (462 patients) was divided into those without contralateral mediastinal or hilar adenopathy (AJCC Stage II/IIIA) and those with (AJCC Stage IIIB), a significant survival (P = 0.0001) was noted with 2-year survival rates of 26% versus 4%, respectively. When AJCC Stage IIIA (348 patients) was divided into the patients without chest wall invasion (RTOG Stage II/III) and those with (RTOG Stage IV), a difference in 2-year survival of 22% versus 10% was observed (P = 0.002). Although both staging systems independently predict for survival, a fusion of both staging systems is the most discriminating of outcome. Future nonoperative studies in locally advanced NSCLC should stratify for contralateral nodal involvement (per AJCC staging) and chest wall invasion (per RTOG staging).

N2 (clinical) non-small cell carcinoma of the lung: prospective trials of radiation therapy with total doses 60 Gy by the Radiation Therapy Oncology Group

Clinical Stage III (N2) non-small cell carcinoma of the lung encompasses a large group of patients, frequently treated with radiation therapy alone, who are now considered to have borderline-resectable tumors. Pilot studies are proceeding which use combinations of resection, radiation therapy, and chemotherapy. To place trials of combination therapy in perspective with contemporary results of radiation therapy alone, recently completed trials of the RTOG were analyzed specifically for clinical Stages T1-3N2. A prospective randomized trial of hyperfractionated radiation therapy (HFX), conducted from 1983 through 1987, compared total doses of 60.0, 64.8, and 69.6 Gy using 1.2 Gy bid with greater than or equal to 4 hr interval. After acute and late effects were considered tolerable, 74.4 Gy and 79.2 Gy arms supplanted the two lowest dose arms. Survival was compared among the five total dose arms, and with 60 Gy in 30 fractions in 6 weeks (standard fractionation-STD) from earlier RTOG studies. Of 516 HFX patients analyzed, 296 (57.3%) with Performance Status (PS) 70-100 and less than 5% weight loss (favorable) had a significantly (p = .001) better survival than those with PS 50-69 or weight loss greater than 5%. Patients with RTOG Stage III (361, 70.0%) experienced better survival (p = .027) than RTOG Stage IV M0. The 69.6 Gy total dose arm was significantly (p = .031) better in favorable RTOG Stage III patients than all other total dose arms: the 1-year survival rate was 58% and the 3-year rate was 20%. The 69.6 Gy HFX results were significantly (p = .002) better than results with STD fractionation in comparable patients from earlier RTOG trials (1-year survival = 30%, 3-year survival = 7%). A prospective, randomized Phase III comparison of STD with 60 Gy versus HFX with 69.6 Gy is underway. These results provide benchmarks for studies of surgical resection combined with chemotherapy and/or radiation therapy until results of prospective comparisons with concurrent controls are available.

A randomized phase I/II trial of hyperfractionated radiation therapy with total doses of 60.0 Gy to 79.2 Gy: possible survival benefit with greater than or equal to 69.6 Gy in favorable patients with Radiation Therapy Oncology Group stage III non-small-cell lung carcinoma: report of Radiation Therapy Oncology Group 83-11

A phase Ilate/II trial of hyperfractionated (HFX) radiation therapy for non-small-cell carcinoma of the lung (NSCCL) was conducted by the Radiation Therapy Oncology Group (RTOG) between 1983 and 1987. Fractions of 1.2 Gy were administered twice daily with greater than or equal to 4 hours between fractions. Patients were randomized to receive minimum total doses of 60.0, 64.8, and 69.6 Gy. After acceptable risks of acute and late effects were found, 74.4 Gy and 79.2 Gy arms were added, and the lowest total dose arms were closed. No significant differences in the risks of acute or late effects in normal tissues were found among the 848 patients analyzed in the five arms; risks of severe or life-threatening pneumonitis were 2.6% for 60.0 to 64.8 Gy, 5.7% for 69.6 to 74.4 Gy, and 8.1% for 79.2 Gy. Among 350 patients who had the same criteria as Cancer and Leukemia Group B (CALGB) protocol 84-33 (American Joint Committee on Cancer Staging [AJCCS], 1984, stage III; Karnofsky performance status [KPS] 70 to 100; less than 6% weight loss), there was a dose response for survival: survival with 69.6 Gy (median, 13.0 months; 2 years, 29%) was significantly (P = .02) better than the lower total doses. There were no differences in survival among the three highest total-dose arms. Comparisons with results in similar patients treated with 60 Gy in 30 fractions of 2.0 Gy 5 days per week for 6 weeks suggest benefit from HFX radiation therapy with 69.6 Gy. Improvement in survival with HFX radiation therapy at 69.6 Gy total dose without increase in normal tissue effects, justifies phase III comparison with standard fractionation alone and combined with systemic chemotherapy in this common presentation of NSCCL.

Use of the day 6 bone marrow to alter remission induction therapy in patients with acute myeloid leukaemia: a leukemia intergroup study

Patients with acute myeloid leukaemia who fail to show substantial bone marrow cytoreduction by day 6 of induction therapy enter complete remission (CR) less frequently than patients with good bone marrow leukaemic cytoreduction. The objective of the current study was to determine whether an increase in the intensity of therapy on days 8, 9 and 10 ('augmentation' of remission induction therapy) for patients with poor bone marrow cytoreduction detected in the day 6 bone marrow could improve the complete remission rate without increasing the number of toxic deaths. Patients from six centres were entered and treated with standard dose ara-C for 7 or 10 d and an anthracycline for the first 3 d. Patients aged less than 60 years and with greater than 30% bone marrow biopsy cellularity or greater than 10% abnormal cells on the aspirate obtained 6 d after the start of therapy were augmented with cytosine arabinoside 3 g/m2 every 12 h on days 8, 9 and 10. Therapy was augmented in 116 of the 252 patients less than 60 years. There was a highly statistically significant difference between augmented and nonaugmented patients (P less than 0.001) for the per cent biopsy cellularity and per cent abnormal cells in the day 6 marrow. The CR rate for augmented patients was 69% and for nonaugmented patients 60% suggesting that augmentation therapy abrogated the prognostic significance of more extensive residual leukaemia in the day 6 bone marrow. The results suggest that augmentation of remission induction for patients with poor bone marrow cytoreduction detected 6 d after initiation of therapy, may salvage patients who are destined to fail remission induction because of resistant disease without producing excessive toxicity.

Intensive remission consolidation therapy in the treatment of acute nonlymphocytic leukemia

A pilot study was conducted to determine the possible efficacy and the toxicities associated with the administration of four courses of intensive consolidation chemotherapy to patients with acute nonlymphocytic leukemia in remission. All therapy was completed within 6 months. The median duration of remission was 22 months, with 45+% of patients in remission at 3 years and few relapses to date thereafter. Sixty percent of patients experienced significant side effects after each course of therapy. The therapy appeared to be particularly efficacious for patients less than 45 years of age, since 65% are alive at 3 years and there is no projection for a median duration of remission as yet. The cytogenetic characteristics of the leukemic cells, the percentage of S phase cells, and the height of the WBC count were the most important prognostic characteristics at diagnosis.

Plasma levels of daunorubicin metabolites and the outcome of ANLL therapy

Levels of plasma daunorubicin, daunorubicinol and aglycone metabolites were measured in 47 patients 3 h after daunorubicin was administered daily for three days as part of a cytosine arabinoside/daunorubicin remission induction regimen. High-pressure liquid chromatography with fluorescence detection was used for separation and quantitation of the drug and its metabolites. A wide range of plasma levels were observed regardless of the outcome of therapy. Patients who had high levels of the drug, or daunorubicinol on day 1 of therapy tended to have high levels on days 2 and 3 of the regimen. Three hours after the third daily dose of daunorubicin was administered, patients who would not enter remission had significantly higher levels of aglycone metabolites in plasma than did patients who entered remission. These data indicate that resistance to chemotherapeutic effects of daunorubicin may be connected with metabolism of the drug, especially with enhanced metabolism to aglycones.

Abrogation of the prognostic significance of low leukemic cell retention of cytosine arabinoside triphosphate by intensification of therapy and by alteration in the dose and schedule of administration of cytosine arabinoside

The ability of leukemic cells to phosphorylate cytosine arabinoside (araC) and retain the triphosphate form of the drug (araCTP) is strongly predictive of remission duration for patients with acute nonlymphocytic leukemia who are treated with araC-based maintenance therapy. An increase in the intensity of therapy improves the overall median duration of remission, the increased intensity of therapy being especially beneficial for patients whose leukemic cells do not retain araCTP. This alteration in therapy reduces the prognostic significance of leukemic cell araCTP retention. Further, it seems that the use of high-dose araC as intensive consolidation therapy and the administration of conventional-dose araC by continuous infusion make it possible to further reduce or even abrogate the adverse prognostic significance of low leukemic cell retention of araCTP.

High-dose cytosine arabinoside as the initial treatment of poor-risk patients with acute nonlymphocytic leukemia: a Leukemia Intergroup Study

Sixty-seven patients with newly diagnosed acute nonlymphocytic leukemia (ANLL) who were considered to be poor candidates for treatment with cytosine arabinoside (ara-C)/anthracycline antibiotic therapy were treated with high-dose ara-C (HDara-C) remission induction therapy. Thirty-four of the 67 patients had a hematologic disorder before developing acute leukemia or had a history of exposure to marrow toxins, 23 patients were greater than 70 years old, and 10 patients had medical problems that were felt to be a contraindication to therapy with an anthracycline antibiotic. Forty-two percent of patients entered complete remission (CR), whereas 22% failed to enter remission because of persistent leukemia. Treatment was associated with substantial toxicity varying from nausea and vomiting to irreversible cerebellar toxicity. Thirty-four percent of patients died during therapy. Poor performance status, a low serum albumin, and a low platelet count were associated with death during remission induction therapy, whereas a high pretherapy leukemic cell mass and a large number of residual leukemic cells in the marrow after six days of therapy were associated with treatment failure due to persistent leukemia.

High-dose cytosine arabinoside in the treatment of preleukemic disorders: a leukemia intergroup study

Fifteen patients with myelodysplastic/myeloproliferative disorders were treated with high-dose cytosine arabinoside therapy. While severe toxicity was produced in every patient, only two of the 15 patients entered complete remission and two achieved partial remission status. The therapeutic responses were confined to patients who had severe myelofibrosis of apparently recent onset.

Prediction of response of patients with acute nonlymphocytic leukaemia to remission induction therapy: use of clinical measurements

Two hundred patients with acute nonlymphocytic leukaemia received remission induction therapy consisting of cytosine arabinoside and an anthracycline antibiotic. Analysis of the pretherapy characteristics of the patients demonstrated that patient age was the most important factor in determining whether or not the patient would survive remission induction therapy. Assessment of the characteristics of the bone marrow after 6 d of therapy permitted the recognition of patients who were likely to fail to enter remission because of persistent leukaemia. Taken together, these observations demonstrate that it is possible to identify patients for whom conventional chemotherapy is not likely to be of benefit either because it is too intensive or because it is not intensive enough to produce a complete remission.

Changes in the characteristics of the bone marrow during therapy for acute non-lymphocytic leukemia: relationship to response to remission induction therapy

The bone marrows of patients with acute non-lymphocytic leukemia being treated with 'high dose' cytosine arabinoside remission induction therapy were sampled prior to the initiation of chemotherapy, after 6 days of therapy and again 7 days after the conclusion of therapy. These studies demonstrated that the marrows of patients who would enter remission (CR patients) contained less leukemic cells prior to therapy than patients who would fail to enter remission because of persistent leukemia (resistant disease, or RD patients). A comparison of the day 6 and 7-day post-therapy marrows with the pretherapy marrow demonstrated that while the % reduction in leukemic cells was greater for CR patients than for RD patients, the absolute reduction in leukemic cell mass was the same for both groups. While there was no relationship between the percentage of cells in S phase and the pretherapy leukemic cell mass, the greater the pretherapy leukemic cell mass the greater the likelihood that the leukemic cells would be resistant to the metabolic effects of cytosine arabinoside in vitro.

Assessment of the drug sensitivity of acute nonlymphocytic leukaemia using the in vitro clonogenic assay

The ability of an in vitro clonogenic drug sensitivity assay to predict the outcome of therapy for acute nonlymphocytic leukaemia was evaluated using marrow cells obtained from previously untreated or first relapsed patients treated with either cytosine arabinoside/anthracycline antibiotic or high dose cytosine arabinoside remission induction therapy. While the per cent of leukaemic cells killed in vitro was correlated with the outcome of therapy, this drug sensitivity assay provided little or no clinically useful information.

Inhibition of DNA synthesis by cytosine arabinoside: Relation to response of acute non-lymphocytic leukemia to remission induction therapy and to stage of the disease

The sensitivity of leukemic marrow cell DNA synthesis to cytosine arabinoside (araC) exposure in vitro was studied in specimens obtained from patients with acute non-lymphocytic leukemia. Cells from patients who had been treated with araC in the past were more likely to be resistant to the effect of araC on DNA synthesis than cells obtained from patients who had not been so-treated previously. Resistance to the effects of araC on DNA synthesis was associated with the failure of high-dose araC therapy to induce remissions in relapsed patients, whereas remission induction failure in previously untreated patients was not associated with araC resistance.

Relationship of the growth of leukemic cells in vitro to the outcome of therapy for acute nonlymphocytic leukemia

Bone marrow cells obtained from 166 patients with acute nonlymphocytic leukemia were cloned in vitro. The number and size of clones produced differed among patients and was unrelated to French-American-British type of leukemia, to patient age, to whether the patient was studied at the time of initial diagnosis or at relapse, or to the cytogenetic (normal or abnormal metaphases) or cell cycle characteristics of the leukemic bone marrow cells. The ability of leukemic cells to clone in vitro was associated with poor response to therapy in vivo, with the remission rate being inversely related to cloning efficiency of the leukemic cells, and with remission durations being inversely correlated with the size of the cluster/colonies formed in vitro. Only an occasional patient whose marrow cells produced clonal growth in vitro and in whom cytogenetic abnormalities were detected entered complete remission with conventional remission induction therapy. Measurement of the clonogenic potential in vitro of leukemic marrow cells together with their cytogenetic type may help to distinguish between patients who should and should not receive cytosine arabinoside/anthracycline antibiotic remission induction therapy and patients who do and do not require intensive remission consolidation chemotherapy.

Relationship between the per cent of marrow cells in S phase and the outcome of remission-induction therapy for acute nonlymphocytic leukaemia

The relationship between the pretherapy cell cycle characteristics of leukaemic marrow cells and the outcome of remission-induction therapy for acute nonlymphocytic leukaemia was studied in newly diagnosed and relapsed patients who were then treated with either combination chemotherapy consisting of cytosine arabinoside/anthracycline antibiotic +/- 6 thioguanine or with single agent high-dose cytosine arabinoside therapy. The outcome of high-dose cytosine arabinoside therapy was highly dependent upon the per cent of pretherapy cells in S phase with no remissions occurring in patients in whom the 3H-TdR labelling index was less than 6%. In contrast, the outcome of cytosine arabinoside/anthracycline antibiotic therapy was independent of the pretherapy cell cycle characteristics of the leukaemic cells.

Relationship between plasma adriamycin levels and the outcome of remission induction therapy for acute nonlymphocytic leukemia

Plasma adriamycin and adriamycinol levels were measured in 45 patients with acute nonlymphocytic leukemia 3 h after the drug was administered. A wide range of levels as found. Plasma levels increased after the administration of each of the three daily doses of the drug. High plasma levels were associated with both death during remission induction therapy and, for patients who entered remission, long remissions.

The clonogenic assay as a reproducible in vitro system to study predictive parameters of treatment outcome in acute nonlymphoblastic leukemia

Seven institutions studied the cloning pattern of leukemic cells from pretherapy bone marrows of 273 patients with newly presenting and relapsed acute nonlymphoblastic leukemia. The cloning assay was done in all centers using an identical double-layer agar method with a common source of colony-stimulating factor. Cells were incubated for seven days, and clones were identified visually with an inverted microscope. All centers were able to obtain clonal growth in a substantial proportion of patients. Differences in growth pattern were observed between the major contributing center and the pooled results for all other centers. However, an analysis of clinical results suggested that in vitro differences were more likely related to differences in the patient populations than to variability in laboratory technique. The proportion of marrows in which leukemic cells formed colonies (greater than 40 cells) and large clusters (20-40 cells) was greater in relapsed patients than in newly presenting patients (P less than .06). A progressive improvement in induction treatment outcome was seen with decreasing clonal growth. Patients whose marrows did not produce clones had a complete remission (CR) rate of 83% versus 50% for those patients whose marrow leukemic cells formed colonies and/or large clusters (P = .05). In vitro drug sensitivity studies with cytosine arabinoside and adriamycin were performed on bone marrow cells of patients treated with this combination clinically. The percent killing of clonogenic cells in this assay correlated with remission induction outcome. Complete remission was obtained in 73% of 15 patients whose bone marrow leukemic cells showed greater than 30% killing by in vitro drug exposure, and CR was obtained in only 30% of 23 patients whose marrows showed less than 30% killing (P less than .01). The results indicate that the clonogenic assay correlates with treatment outcome and can be used for drug sensitivity testing in patients with acute nonlymphoblastic leukemia. The limitations of the assay are discussed.