Treatment of leukemia with large doses of methotrexate and folinic acid: clinical-biochemical correlates.

Patients with acute leukemia were given repeated cycles consisting of infusions of methotrexate followed by "rescue" with folinic acid. Peripheral blood leukemic cells were harvested from patients before cyclical treatment, and the rates of incorporation of thymidine and of deoxyuridine into deoxyribonucleic acid (DNA) were measuared in vitro. There was no relationship between the pretreatment incorporation of either deoxynucleoside into DNA and the clinical response to therapy. Methotrexate suppressed deoxyuridine incorporation into DNA by the leukemic blasts in vitro, but the patients whose cells were most sensitive to this effect did not necessarily go into remission when treated. Leukemic cells were sampled during methotrexate infusions and the deoxynucleoside incorporation rates were determined. Thymidine incorporation into DNA was variably affected. If, by the end of the first infusion, it remained elevated, remission rarely followed, whereas if it was below the pretreatment value, remission was much more likely. In all cases, deoxyuridine incorporation was suppressed during the infusion. The greatest suppression occurred in patients who went on to remission, but the suppression did not correlate with that expected from pretreatment in vitro tests unless due weight was given to the concomitant effects of the methotrexate therapy on thymidine incorporation. Leukemic blasts surviving successive cycles of therapy became progressively more resistant to the suppressing effects of methotrexate in vitro. This resistance became especially marked in the blasts of patients who did not go into remission. During methotrexate infusions, inhibition of leukemic cell dihydrofolate reductase activity was greatest in blasts of patients whose disease subsequently remitted.

The mechanism of action of methotrexate in cultured L5178Y leukemia cells.

This study investigates the relationships between the methotrexate (MTX)-induced purineless state and thymineless state and between the thymineless state and the kill of L5178Y cells. As an index of the thymineless state, we measured the effect of MTX on conversion of deoxyuridylate to thymidylate. This was measured as the rate of incorporation of tritiated deoxyuridine into DNA, but it was corrected for changes in incorporation of tritiated thymidine. Thus we derived the "calculated tritiated deoxyuridine rate." During the MTX treatment, the calculated tritiated deoxyuridine rate decreased rapidly at first and then more slowly. The slow 2nd-phase block was not reversed by hypoxanthine. As the 2nd-phase block deepened, the lymphoblasts continued to die (loss of cloning ability) but recovered the ability to incorporate tritiated thymidine into DNA. After 7 hr of MTX treatment, the kinetics of the 2nd-phase block in calculated tritiated deoxyuridine rate correlated closely with the kinetics of cell kill. Thus, MTX may inhibit dihydrofolate reductase enzyme, rapidly deplete S-phase L5178Y of reduced folates, and thus produce a purineless and thymineless state. As treatment continues, MTX intensifies the thymineless state, possibly by direct inhibition of thymidylate synthetase enzyme, and the cells die predominantly a thymineless death. The purineless state initially contributes to cell kill but later does not, possibly because it partially reverses spontaneously.

Consequences of methotrexate inhibition of purine biosynthesis in L5178Y cells.

Addition of 1 muM methotrexate to cultures of L5178Y cells results in an initial inhibition of thymidine, uridine, and leucine incorporation into acid-insoluble material followed, after about 10 hr, by a partial recovery in the extent of incorporation of these precursors. Acid-soluble adenosine triphosphate and guanosine triphosphate concentrations are greatly reduced initially, but guanosine triphosphate concentrations appear to recover partially by 10 hr. Acid-soluble uridine triphosphate and cytidine triphosphate concentrations initially increase after methotrexate treatment but then, with time, they too decline. Hypoxanthine and guanine are more effective than is adenine in overcoming the methotrexate-induced inhibition of thymidine incorporation. These results suggest that, in the presence of methotrexate, guanine nucleotides become limiting for nucleic acid synthesis before adenine nucleotides do. The block of purine de novo synthesis in L5178Y cells by methotrexate is almost complete and is not reversed with time. This suggests that the additional purine nucleotides that are available for nucleic acid synthesis 8 to 10 hr after addition of methotrexate are being derived from nucleic acid breakdown. Consistent with this is the observed reduction in the number of polyribosomes and hence, presumably in messenger RNA levels.

Dose intensity analysis of chemotherapy regimens in ovarian carcinoma.

The relationship between outcome and dose intensity was analyzed for first-line chemotherapy of advanced ovarian cancer using a particular CHAP (cyclophosphamide, hexamethylmelamine, Adriamycin [Adria Laboratories, Columbus, OH], cisplatin) regimen as the standard. Previously described techniques were used to calculate the average dose intensity of regimens containing one, two, three, or all four drugs of CHAP, relative to the standard. The average relative dose intensity, especially the relative dose intensity of cisplatin, correlated significantly with clinical response and with median survival time (MST) of the entire group (not just the remitters). There was a distinct advantage for multiagent regimens over single alkylating agents and especially for multiagent regimens containing cisplatin. Survival correlated with response rate (of multiagent regimens). This analysis suggests that dose intensity is a determinant of treatment outcome. Prospective randomized trials would be required to test whether, and to what extent, dose intensity determines outcome independently of total amount of drug given, performance status, or other factors. If dose intensity does determine outcome, methods of increasing it should be tested in an attempt to improve treatment results.

Co-trimoxazole prophylaxis during high-dose chemotherapy of small-cell lung cancer.

In 103 patients with small-cell lung cancer, we compared four courses of standard doses of Adriamycin (A) (Adria Laboratories, Columbus, Ohio), vincristine (V), and cyclophosphamide (C) with a regimen of increased doses of cyclophosphamide and to a lesser extent, Adriamycin. We found no significant difference in rate (22% v 21%) or median duration (seven v nine months) of complete remission. Patients not in complete remission after the four cycles of AVC received two courses of VP-16 (etoposide) and cisplatin: the complete remission rate increased to 49% and 48% respectively. Patients on the high-dose arm received co-trimoxazole prophylaxis; those on the standard arm did not. Patients on the high-dose arm had a higher incidence of neutropenia (nadir less than 500 cells/microL) but a lower incidence of infection for similar degrees of neutropenia. However, they also suffered more severe side effects of a different kind. Cotrimoxazole thus allowed for the administration of higher doses of chemotherapy to outpatients by protecting them from infection. However, the higher doses of cyclophosphamide and Adriamycin, did not improve treatment results, produced more severe side effects, and is not recommended.

The role of dose intensity in determining outcome in intermediate-grade non-Hodgkin's lymphoma.

To determine whether the dose intensity of chemotherapeutic regimens correlates with the complete remission rate in adult patients with advanced-stage intermediate-grade lymphoma, reports of comparative trials of therapy were reviewed. Reports were identified using MEDLINE, through references from review articles, and through review of selected abstracts. Twenty-two studies including 14 randomized and eight cohort trials were analyzed to assess projected dose intensity. Four other studies were analyzed to assess the role of received dose intensity. Dose intensities were calculated using described methods and correlated with complete remission rates. Individual trials were assessed using "levels of evidence." A metaanalysis of randomized trials and a cross-trial analysis of all comparative trials using a weighted least squares linear regression were performed. Using levels of evidence, support was obtained for the hypothesis that dose intensity correlates with the remission rate from two trials in which dose intensity was "indirectly" tested. As these studies did not "directly" test dose intensity, confounding variables, including those arising from the assumptions made in calculating dose intensity, cannot be excluded. Metaanalysis showed a relative probability of achieving complete remission of 1.34 (95% confidence interval, 1.13 to 1.58) favoring the pooled arm of high dose intensity. Cross-trial analysis showed a relatively weak association between dose intensity and remission rate (r = .49, P = .0001). Two of four reports retrospectively assessing received dose intensity suggested that increased dose intensity is associated with superior remission rates. These analyses suggest that dose intensity may correlate with the remission rate in advanced-stage intermediate-grade lymphoma. However, properly designed trials directly testing dose intensity have not been performed and are needed to confirm this hypothesis.

Quality of life in stage II breast cancer: an instrument for clinical trials.

A questionnaire has been developed for use as an outcome measure in clinical trials of adjuvant chemotherapy in women with stage II breast cancer. The selection of items for this Breast Cancer Chemotherapy Questionnaire (BCQ) was based on the problems and experiences felt to be most important by women undergoing adjuvant chemotherapy. The BCQ consists of 30 questions that focus on loss of attractiveness, fatigue, physical symptoms, inconvenience, emotional distress, and feelings of hope and support from others. The BCQ, other instruments that evaluate quality-of-life (Spitzer, Karnofsky, and Rand), and patient and physician global assessments were administered serially to 418 patients taking part in a randomized trial comparing a 12-week regimen and a 36-week regimen of adjuvant chemotherapy. The validity of the BCQ is supported by its correlation with the Rand Emotional (r = .58), Rand Physical (r = .60), and Spitzer (r = .62) questionnaires. The BCQ correlated more strongly with global ratings of both physical and emotional function by the patients and their physicians than the other instruments. A comparison of the quality-of-life outcomes of patients in the two treatment groups in the period beyond 3 months after initiation of treatment, when one group had completed the treatment course and the other was still on treatment, revealed that the BCQ and Karnofsky were the only instruments able to demonstrate differences between the groups (P less than .0001). Hence, the BCQ is a valid and responsive method of assessing treatment-related morbidity in patients receiving adjuvant chemotherapy for stage II breast cancer.

A randomized trial comparing 12 weeks versus 36 weeks of adjuvant chemotherapy in stage II breast cancer.

A randomized trial has been performed in which women with axillary node-positive breast cancer were allocated to either a short intensive 12-week chemohormonal treatment consisting of cyclophosphamide, methotrexate, fluorouracil, vincristine, prednisone, Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and tamoxifen (CMFVP plus AT) or 36 weeks of CMFVP. The median follow-up is 37 months. Of the 222 women randomized to the 12-week treatment, 113 (50.9%) have experienced either recurrence or death as compared with 90 patients (41.9%) in the 36-week treatment group. The corresponding 3-year relapse-free survivals are 55% and 64%, respectively, P = .003. Fifty-nine (26.6%) of the patients in the 12-week group have died compared with 46 (21.4%) of the 36-week group. The corresponding 3-year survival rates are 78% and 85%, respectively, P = .04. A Cox regression analysis showed an associated increased risk ratio for recurrence or death of 1.7, P = .003, and for death of 1.8, P = .017 in the 12-week treatment group compared with the 36-week group. Thus, this 12-week regimen of adjuvant chemohormonal therapy is inadequate treatment for women with axillary node-positive breast cancer; possible explanations for this inferiority are its shorter duration and/or a negative interaction of tamoxifen on the chemotherapy.

Prospective randomized trial of one-hour sequential versus simultaneous methotrexate plus 5-fluorouracil in advanced and recurrent squamous cell head and neck cancer.

Results from experimental systems suggest that the combination of methotrexate (MTX) and 5-fluorouracil (5-FU) produces synergistic cytotoxic effects that are dependent on the sequence of drug administration. Biochemical studies have demonstrated plausible mechanisms of a synergistic effect when MTX precedes 5-FU. A variety of phase I and phase II studies have employed this sequential combination with promising but inconclusive results. In this study, 79 evaluable patients with squamous cell head and neck cancer were randomized to receive MTX (200 mg/m2 IV) and 5-FU (600 mg/m2 IV) either simultaneously or sequentially with MTX preceding 5-FU by one hour. All patients were ambulatory and patients were stratified as to whether they presented with primary disease or with recurrence after prior radiation and/or surgical therapy. The overall response rate was superior for simultaneous therapy (62%) compared with sequential therapy (38%) (p less than 0.06). Among patients with primary head and neck cancer, the stage of the disease influenced the response rate. Eight of nine stage III patients who received simultaneous therapy responded while none of the four patients who received sequential therapy responded (p less than 0.01). This study demonstrates that one-hour sequential MTX plus 5-FU is not superior to simultaneous treatment in patients with squamous cell head and neck cancer.

Applications of dose intensity to problems in chemotherapy of breast and colorectal cancer.

Studies were analyzed to show the correlation of response with dose intensity of single-agent 5-fluorouracil (5-FU) against colorectal cancer, multiagent CMF (cyclophosphamide, methotrexate, 5-FU) regimens against advanced breast cancer, and adjuvant therapy in stage II breast cancer. In colorectal cancer studies, subgroups in which 5-FU was given by intravenous (IV) bolus, infusion, and orally were analyzed. One study reported delivered dose levels after reductions for toxicity. This allowed calculations of received dose intensity for the three dose levels, and comparison with projected dose intensities. The data suggest that the dose-intensity response line is steep, once a threshold dose intensity has been surpassed. An increase of only 100 mg/m2/wk of received dose intensity of 5-FU increased the response rate from 20% to 29%, which in relative terms was an increase of almost 50%. Received dose intensity may correlate with response, not only in groups of patients, but also in individual patients, and this may, in fact, be the most important application of the concept of dose intensity.

Total skin electron irradiation for mycosis fungoides: failure analysis and prognostic factors.

From 1970 to 1980, 106 patients with mycosis fungoides received total skin electron irradiation to full tolerance. The majority received 30 Gy of 3 MeV electrons in 12 treatments over three weeks. Eighty-eight patients had received prior therapy. Fifty patients had cutaneous plaques only (T1-2N0), and 56 had more advanced disease. At five years, actuarial survival is 66.7% and disease-free survival 21.4%. The median time to relapse is 12 months; prolonged survival is seen only with complete response. Compared with more advanced stages, T1-2N0 patients have more frequent complete response (96% vs 71%) and better relapse-free survival at five years (32 vs 7%). Of 14 patients with T2 disease in continuous complete remission for from 45-113 months, only one has relapsed. This suggests that cure is possible in up to 26% of patients with T2 disease who achieve complete response. In advanced stages, complete response is more likely with doses over 25 Gy (80 vs 50%). First recurrences were predominently in sites of previous involvement. Death resulted mainly from extracutaneous dissemination or failure to induce remission.

"Decadose" effects of cisplatin on squamous cell carcinoma of the upper aerodigestive tract. II. Clinical studies.

There is evidence that solid tumors rapidly acquire cellular resistance to cisplatin. This resistance is usually mild to moderate and could be circumvented with higher concentrations of drug exposure if ancillary methods were available to avoid systemic cytotoxicity. The purpose of this study was to determine whether a tenfold increase in dose (decadose) would overcome cisplatin resistance. In a clinical trial, response effects of cisplatin at dose intensities ranging from 32.5 to 200 mg/m2 per week, which were delivered by highly selective intra-arterial infusions with a simultaneously administered intravenous neutralizing agent, were measured in 31 patients with squamous cell carcinoma (SCC) of the upper aerodigestive tract (UADT). The overall response rate (complete response [CR] and partial response [PR] to cisplatin therapy at dose intensity intervals of 0 to 74, 75 to 149, and 150 to 200 mg/m2 per week were 45.5%, 72.7%, and 100%, respectively. The average received dose intensities for nonresponders and responders (CR and PR) were 57.8 and 120.7 mg/m2 per week, respectively (P = .031). The results indicate that resistance to standard doses of cisplatin by SCC of the UADT, both previously untreated and recurrent, can be substantially overcome with "decadose" cisplatin therapy. Progress toward improving survival of patients with head and neck cancer, and possibly other site-specific malignancies, may be achieved by incorporating decadose cisplatin therapy into a multimodality treatment plan.