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* From the Brown University Oncology Group, Providence, RI.
Correspondence to: Wallace Akerley III, MD, Rhode Island Hospital, Division of Oncology, 593 Eddy St, Providence, RI 02903; e-mail: akerley{at}brown.edu
| Abstract |
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Design: Patients with stage IIIB/IV NSCLC were eligible if they had a performance status of 0 to 2, no previous chemotherapy, and normal organ function. Paclitaxel was administered as a 3-h infusion weekly for 6 weeks of an 8-week cycle. Doses were modified for toxicity observed on the day of treatment.
Measurements and results: Paclitaxel, 100 to 200 mg/m2/wk, was administered in the phase I trial. Dose escalation was limited primarily by neutropenia, and a relationship between dose and response was noted. A phase II trial of paclitaxel, 175 mg/m2/wk, the maximum tolerated dose, was initiated; data are available for the first 25 patients. Eighty-three, 75, 58, and 50% of intended doses were delivered during cycles one to four, respectively. Grade 2 or 3 neuropathy occurred in nine patients, but improved in all following dose reduction. Platelet counts rose by 17,000/µL/wk. Partial responses occurred in 14 of 25 patients (56%; confidence interval, 46 to 66%). The duration of response was 6 months, and 1-and 2-year survival rates were 53% and 18%, respectively.
Conclusion: Paclitaxel administered on a weekly schedule allows enhanced dose intensity, has a protective or stimulatory effect on platelets, and is active in NSCLC.
Key Words: dose intensity maximum tolerated dose non-small cell lung cancer paclitaxel platelets
| Introduction |
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We recently completed two phase I trials using weekly administration of paclitaxel with radiation to take advantage of the properties of paclitaxel as a radiosensitizer. For patients with unresectable stage III NSCLC, the maximum tolerated dose (MTD) of a 3-h paclitaxel infusion administered with 60 Gy of thoracic radiation (2 Gy/d) was 60 mg/m2 for each of 6 consecutive weeks.12 Esophagitis, limited to the radiation field, precluded further dose escalation. Paradoxically, the anticipated toxicities of myelosuppression, neuropathy, and alopecia were not noted, even though a dose intensity equivalent to 210 mg/m2 every 21 days was achieved.
In a similar phase I trial using weekly paclitaxel with cranial radiation in adult brain cancer, significantly greater doses were delivered with the same amelioration of toxicity.13 Based on this apparent schedule-dependent moderation of toxicity, the Brown University Oncology Group initiated a series of trials designed to examine the response to extended delivery of weekly paclitaxel without radiation for patients with disseminated NSCLC.
| Phase I Trial of Weekly Paclitaxel |
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The initial dosage of paclitaxel was 100
mg/m2/wk. Three consecutive patients were entered
at each dose level. If < 80% of the scheduled cumulative dose of
paclitaxel in the first cycle was delivered, grade 2 neurotoxicity or
grade 3 nonhematologic toxicity developed in any patient, the level was
expanded to six patients. Unacceptable toxicity was established when
50% of patients at a dose level met these criteria; the MTD was
defined as the dose preceding this level. If dose-limiting toxicity did
not occur, three new patients were entered to the subsequent dose
levels, planned at 125, 135, and 150 mg/m2, with
further increases at 25-mg/m2 increments.
Paclitaxel doses were modified for toxicity determined on the day of treatment (Table 1) . In the event of granulocyte counts < 1,800/µL or platelet counts < 100,000/µL, the paclitaxel dose was decreased by 50%; when granulocyte counts were < 1,000/µL or platelet counts < 75,000/µL, a dose was omitted. In addition, doses were decreased by 50% when grade 2 sensory or motor neuropathy occurred, and were omitted in the event of grade 3 or grade 4 neuropathy. When a dose reduction for neuropathy occurred, all future doses for that patient were limited to 50% of original dose, regardless of degree of neurologic recovery. Other grade 3 and grade 4 toxicities also triggered dose omission.
Results
There were 26 patients entered at six dose levels. Two patients
were ineligible to be evaluated for toxicity, one due to underlying
liver disease and the other due to volitional withdrawal before
completion of the first cycle. Three patients received paclitaxel at
each of the dosage levels: 100, 125, 135, and 150
mg/m2/wk. All but one dose was received, and no
grade 3/4 toxicity directly attributable to paclitaxel occurred
during the first cycle. One patient at the
125-mg/m2 level developed an uncomplicated
pneumonia that was not associated with neutropenia. One patient
receiving 150 mg/m2 required a transfusion of
RBCs, and a second patient developed Aspergillus esophagitis (possibly
related to steroids). At the 175-mg/m2 dose
level, patient accrual was expanded to six due to dose reductions
for asymptomatic neutropenia (absolute neutrophil count [ANC]
< 1,000/µL), which caused two patients to receive < 80% of the
scheduled dose. The remaining four patients received full doses without
excessive toxicity.
Six patients were entered to receive 200 mg/m2/wk, but only one completed the first cycle without dose reduction or undue toxicity. This patient subsequently developed a grade 3 sensory-motor neuropathy and a grade 3 rash at the beginning of the second cycle. The remaining five patients received < 80% of the intended dose for a variety of reasons. Thus, dose escalation was ceased at 200 mg/m2/wk, and 175 mg/m2/wk was defined as the MTD.
Ten patients who did not demonstrate disease progression were available for evaluation of long-term toxicity. Subsequent courses were delivered at the initially assigned dose level. The only patient continuing therapy at the 200-mg/m2 dose level was reassigned to 175 mg/m2 when it was established as the MTD. A maximum of 12 cycles were delivered: three patients completed 2 cycles, two patients completed 3 cycles, one patient each completed 4, 5, 6, and 12 cycles. All but two patients discontinued therapy on eventual disease progression. One patient withdrew after three cycles (24 weeks), and the last patient withdrew for prolonged neuropathy.
Neuropathy was both cumulative and dose-related. Grade 2 and grade 3 neuropathy occurred in five patients (21%). Grade 3 neuropathy developed in one patient at the 175-mg/m2 dose level during the second cycle, and in another at the 200-mg/m2 dose level following the first cycle. Symptoms improved to grade 2 in both patients, and therapy was reinstituted with a 50% dose reduction. Grade 2 neuropathy developed in one patient at 175 mg/m2 (third cycle), in one patient at 200 mg/m2, and in one patient at 125 mg/m2 (fifth cycle). Symptoms improved with dose reduction in all of these cases. Many patients noted subjective improvement in symptoms during the scheduled breaks at weeks 7 and 8, which may have contributed neurologic tolerance.
Responses and survival were greater for dosages of paclitaxel
175
mg/m2/wk. Although response occurred at the
highest and lowest levels, 3 of 12 patients responded at dosages of
paclitaxel < 175 mg/m2/wk, but 6 of 12 patients
responded at higher doses. In addition, survival was significantly
longer (24.9 weeks vs 45.1 weeks; p < 0.01 log-rank) for dosages
175 mg/m2/wk.
| Phase II Trial of Weekly Paclitaxel |
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Results
The following are preliminary data from the first 25 of 30
patients entered on this trial. There were 18 men and 7 women, with a
median age of 65 years (range, 37 to 78 years). Stage IV disease
occurred in 24 patients, and 14 patients had received prior radiation
treatment. Brain metastases had been previously treated in 11 patients.
Eighty-three percent of the intended first cycle dose was delivered due to scheduled dose modification. Doses were reduced, most commonly for neutropenia, especially in the third and sixth weeks, but blood count recovery was rapid. Figure 1 shows counts for a representative patient. In cycles 2 to 5, 75%, 58%, 50%, and 50% of intended doses were delivered, respectively.
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An analysis of hematologic toxicity was remarkable for an unanticipated rise in platelets (Fig 2 ). During each week of therapy, the platelet count rose by 17,000/µL per week and dropped back to normal between cycles. This cumulative rise approximates 100,000/µL/6-week course. A similar trend was observed during each of the first three cycles, and was not affected by whether patients received more or less than four of the six intended doses. No thrombotic events were recorded during this trial.
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| Discussion |
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The rising platelet count noted during paclitaxel treatment is a novel observation. It appears to be independent of the weekly schedule because it occurred whether patients received more or less than four of the planned six doses. It is possible that the concurrent use of dexamethasone may have contributed, but we believe it to be an independent effect of the paclitaxel. It likely has been overlooked in other single-agent paclitaxel trials because toxicity scoring systems only highlight platelet declines. This phenomenon may explain the reports of improved platelet tolerance following carboplatin when paclitaxel is administered concurrently.15
Despite the apparent amelioration of toxicity associated with this
weekly schedule, the response rate of > 50% compares favorably with
other single-agent trials (10 to 24%) or multiagent trials (30 to
63%) in advanced NSCLC. The 1- and 2-year survival rates of 53% and
18%, respectively, are also quite substantial when one considers the
large fraction of these patients (40%) with preexisting brain
metastases and the low number of stage IIIB patients included. Another
important observation is the suggestion of improved efficacy of
response rates and survival noted at dosages
175/m2/wk. Further investigation will be
required to determine whether the activity observed in this trial is
due to enhanced dose intensity, the weekly schedule, the frequency of
paclitaxel levels exceeding a threshold dose, or a combination of these
factors. A randomized trial is needed to compare the relative efficacy
of the weekly schedule vs a conventional schedule.
| Footnotes |
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| References |
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This article has been cited by other articles:
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M. Neubauer, J. Schwartz, J. Caracandas, P. Conkling, D. Ilegbodu, T. Tuttle, and L. Asmar Results of a Phase II Study of Weekly Paclitaxel Plus Carboplatin in Patients With Extensive Small-Cell Lung Cancer With Eastern Cooperative Oncology Group Performance Status of 2, or Age >= 70 Years J. Clin. Oncol., May 15, 2004; 22(10): 1872 - 1877. [Abstract] [Full Text] [PDF] |
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P. Fidias, J. G. Supko, R. Martins, A. Boral, R. Carey, M. Grossbard, G. Shapiro, P. Ostler, J. Lucca, B. E. Johnson, et al. A Phase II Study of Weekly Paclitaxel in Elderly Patients with Advanced Non-Small Cell Lung Cancer Clin. Cancer Res., December 1, 2001; 7(12): 3942 - 3949. [Abstract] [Full Text] [PDF] |
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