Phase I study of weekly outpatient paclitaxel and concurrent cranial irradiation in adults with astrocytomas

PURPOSE

Astrocytomas are extremely resistant to currently available treatments. Cranial irradiation is a mainstay of frontline therapy, but tumor recurrence is nearly universal. Paclitaxel has shown antitumor efficacy against astrocytoma cell lines, and is a potent radiosensitizer. For these reasons, we conducted a phase I study of weekly paclitaxel and concurrent cranial irradiation in patients with newly diagnosed astrocytomas.

PATIENTS AND METHODS

Patients with astrocytomas were eligible for this study following initial surgery if they had a Karnofsky performance score (KPS) > or = 60%; normal hematologic, liver, and renal function; and could give informed consent. Beginning on day 1 of treatment, patients received paclitaxel by 3-hour infusion once weekly for 6 weeks, concurrent with standard cranial irradiation. Pharmacokinetic studies were performed on 10 patients.

RESULTS

Sixty patients were enrolled; 56 were fully assessable. Forty-eight had glioblastomas (GBMs), 10 anaplastic astrocytomas (AAs), and two astrocytomas. Age ranged from 21 to 81 years (median, 55); KPS ranged from 60 to 100 (median, 70). The paclitaxel dose was escalated from 20 mg/m2 to 275 mg/m2. No clinically significant anemia or thrombocytopenia occurred. Only one patient (175 mg/m2) became neutropenic. Sensory neuropathy was dose-limiting. The maximum tolerated dose (MTD) was 250 mg/m2. Paclitaxel pharmacokinetic profiles in study patients were identical to those of previously reported patients with other solid tumors.

CONCLUSION

The MTD of paclitaxel administered weekly for 6 weeks by 3-hour infusion is 250 mg/m2. Since patients with brain tumors often have preexisting neurologic deficits, we suggest 225 mg/m2 as the optimum dose for phase II trials in this group of patients.

Combined-modality therapy for advanced non-small cell lung cancer: paclitaxel and thoracic irradiation

Despite advances in the modalities used to treat non-small cell lung cancer (NSCLC), the frequency of locoregional and distant relapses necessitates further enhancement of the therapeutic program. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has demonstrated clinical efficacy against NSCLC and in vitro studies support its role as a radiation potentiator at concentrations achievable in vivo. Thus, a phase I study of weekly paclitaxel and daily concurrent thoracic radiation was conducted in patients with advanced NSCLC to determine (1) the maximum tolerated dose of paclitaxel administered on an outpatient basis for 6 consecutive weeks with daily radiation and (2) the toxicities of the paclitaxel/radiation combination. Paclitaxel was administered as a 3-hour infusion, repeated weekly for 6 weeks with the usual premedication regimen for hypersensitivity prophylaxis. The starting dose of paclitaxel was 10 mg/m2/wk, which was increased by 10 mg/m2 in successive cohorts of three new patients, as tolerated. Radiation therapy was delivered as 40 Gy in 20 fractions to the original volume with a boost of 20 Gy in 10 fractions to the primary tumor. Doses were escalated from 10 to 70 mg/m2/wk. Of the 23 patients evaluable for response, one had stage II NSCLC, four had stage IIIA, 17 had stage IIIB, and one had stage IV. Severe esophagitis (grade 4) occurred in two of the three patients treated at 70 mg/m2 and was dose limiting. One patient discontinued therapy due to hypersensitivity, two developed grade 3 neutropenia, and one developed radiation pneumonitis. With a median follow-up of 7 months, 15 of the 23 patients remain alive. Four had a complete response and 13 had a partial response, for an overall response rate of 74% (95% confidence interval, 52% to 90%). The schedule of weekly paclitaxel and daily thoracic radiation appears active in NSCLC and can be delivered safely in the outpatient setting. The principal dose-limiting toxicity is esophagitis, and the maximum tolerated dose of paclitaxel for this schedule is 60 mg/m2/wk. A phase II trial of weekly paclitaxel 60 mg/m2 and radiation has been initiated in patients with NSCLC.

Weekly, outpatient paclitaxel and concurrent cranial irradiation in adults with brain tumors: preliminary results and promising directions

In a phase I study, paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) was given weekly by 3-hour infusion for 6 weeks concurrent with daily cranial irradiation as initial treatment for patients with newly diagnosed astrocytic brain tumors. The primary goal of the study was to establish the maximum tolerated dose of paclitaxel when administered by this schedule. Sixty patients were entered into the study and received at least one course of therapy. Fifty-six patients completed treatment. The treatment regimen was well tolerated, with minimal hematologic toxicity. Peripheral neuropathy was dose-limiting. Median survival was 9.2 months for patients with glioblastoma multiforme and has not been reached for patients with anaplastic astrocytoma or astrocytoma. The maximum tolerated dose of paclitaxel in this study was 250 mg/m2 administered weekly. However, because five of six patients receiving this dose of paclitaxel developed peripheral neuropathy, and because patients with brain tumors may adapt to a superimposed neuropathy less well than patients without pre-existing nervous system dysfunction, we propose 225 mg/m2 as the recommended dose for subsequent phase II trials.

Preliminary analysis of a phase II study of weekly paclitaxel and concurrent radiation therapy for locally advanced non-small cell lung cancer

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) is an attractive agent to combine with radiation for non-small cell lung cancer. We have been conducting clinical trials of weekly paclitaxel and concurrent radiation therapy. In a phase I study in non-small cell lung cancer, we determined the maximum tolerated dose of paclitaxel to be 60 mg/m2/wk with radiation. Patients received paclitaxel 60 mg/m2/wk as a 3-hour infusion for 6 weeks with radiation to the primary tumor and regional lymph nodes (40 Gy) followed by a boost to the tumor (20 Gy). From March 1994 to February 1995, 33 patients have been entered by the Clinical Oncology Group of Rhode Island. The overall response rate (complete plus partial responses) of 25 evaluable patients as of March 1995 was 84%, with a confidence interval of 68 to 96. The major toxicity was esophagitis. Twenty percent of patients had grade 4 esophagitis. Only 8% of patients had grade 3 neutropenia. Combined-modality therapy with paclitaxel and radiation is a promising treatment for locally advanced non-small cell lung cancer with a high response rate and acceptable toxicity.

Paclitaxel disposition in plasma and central nervous systems of humans and rats with brain tumors

BACKGROUND

Paclitaxel (Taxol) has been shown to sensitize some malignant cells to the effects of radiation. A number of clinical protocols, combining paclitaxel with radiation therapy, have been designed to exploit this phenomenon. The radiation-potentiating effect of paclitaxel is likely dependent on the ability of the drug to penetrate the tissue being radiated. Paclitaxel is known to have limited access to the central nervous system (CNS) of rats and mice, but its ability to penetrate malignant tissue in the CNS is inadequately documented.

PURPOSE

Our purpose was to examine the concentrations of paclitaxel in the cerebrospinal fluid (CSF) of patients with CNS malignancies and in normal and malignant tissues from the brains of Fischer rats bearing the C6 rat glioma and then to compare those paclitaxel concentrations with concomitant paclitaxel concentrations in the plasma of those same patients and animals.

METHODS

Four patients were treated with 3-hour infusions of paclitaxel at doses between 90 and 200 mg/m2. Plasma and CSF were sampled at 0.33, 1.5, 3.25, 5, 6, and 24 hours after initiation of the paclitaxel infusion. Four Fischer rats had 20,000 C6 glioma cells stereotactically implanted into their right frontal lobes; 28 days later, they were given 3-hour infusions of paclitaxel at 10 mg/kg. Plasma was sampled during the paclitaxel infusion. At the completion of the infusion, rats were killed, and portions of their normal and malignant CNS tissues were removed for histologic assessment. Concentrations of paclitaxel in plasma, CSF, and brain tissue were determined with high-pressure liquid chromatography.

RESULTS

Plasma pharmacokinetics of paclitaxel in patients with brain tumors were comparable to those previously described in patients with other malignancies. Paclitaxel could be measured in CSF of all patients, but concentrations were very low. Peak paclitaxel concentrations in CSF ranged between 5 and 83 nM and occurred between 3.25 and 5 hours after initiation of the paclitaxel infusion. Peak paclitaxel concentrations in CSF were between 0.12% and 8.3% of those present in concomitant plasma samples. Paclitaxel was not detectable in the normal or malignant CNS tissue of any rat, despite the fact that plasma concentrations of paclitaxel at the time of tissue acquisition ranged from 0.62 to 153 microM.

CONCLUSIONS

Paclitaxel has only limited access to the CSF of patients with CNS malignancies and to normal and malignant CNS tissues of rats bearing brain tumors.

IMPLICATIONS

The utility of combining paclitaxel with radiation therapy to treat CNS malignancies should be considered in light of the documented limited access of paclitaxel to the CNS.

Diagnosis, management, and survival of patients with leptomeningeal cancer based on cerebrospinal fluid-flow status

BACKGROUND

The authors assessed cerebrospinal fluid (CSF) flow in patients with carcinomatous meningitis using technetium-99m-DTPA (Tc-99) ventriculography to determine the frequency of flow abnormalities, their reversibility with treatment, and the implications for successful therapy and survival.

METHODS

Technetium-99m-DTPA flow studies were performed in 31 patients after placement of Ommaya reservoirs (Baxter, McGaw Park, IL). Two millicuries of Tc-99 were injected into the reservoir. Planar images of the head and entire spine were obtained after 10 and 30 minutes and after 1, 4, 6, and 24 hours. Follow-up studies were performed for 12 patients whose initial studies were abnormal or who developed complications of therapy.

RESULTS

In 19 of the 31 patients (61%), ventricular-outlet, spinal, or convexity blocks were identified. In 11 of these 19 patients, focal radiotherapy to the site of the block restored normal flow. Survival among patients with initially normal, abnormal but correctable, and abnormal but uncorrectable CSF flow differed significantly (6.9, 13.0, and 0.7 months respectively; P < 0.001). Some patients who were treated intrathecally despite abnormal CSF flow experienced drug-related toxicity.

CONCLUSIONS

Cerebrospinal fluid-flow blocks are common in patients with carcinomatous meningitis and may occur at the skull base, in the spinal canal, and over the convexities. These flow abnormalities often can be corrected with appropriately directed radiotherapy. If untreated, CSF tumor progression (protected site effect), neurotoxicity (high concentration effect), and systemic toxicity (reservoir effect) can occur, resulting in shortened survival and treatment-related morbidity. Therefore, intrathecal chemotherapy should be preceded by a radionuclide flow study and should be delayed if abnormal flow is documented until appropriate radiotherapy reestablishes normal flow.

Paclitaxel as a radiation sensitizer in non-small cell lung cancer

The new anticancer agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has demonstrated in vitro radiation-sensitizing effects. In this phase I study, paclitaxel in escalating doses was administered weekly with concurrent radiation therapy to patients with regionally advanced non-small cell lung cancer (NSCLC). The goal was to determine the maximum tolerated dose of paclitaxel in this combination, to identify toxicities, and to evaluate response. Twenty-seven patients with NSCLC were enrolled into a phase I trial of concurrent paclitaxel and radiation therapy administered as a 3-hour infusion each week for 6 weeks. The paclitaxel doses ranged from 10 to 70 mg/m2/wk. Radiation therapy was delivered with weekly paclitaxel as 40 Gy in 20 fractions to the original volume with a boost of 20 Gy in 10 fractions to the primary tumor. Esophagitis was the dose-limiting toxicity at a maximum tolerated dose of 60 mg/m2/wk. The combination of concurrent radiation therapy and weekly outpatient paclitaxel can be safely delivered to patients with NSCLC at a dose of 60 mg/m2. Esophagitis appeared to be the dose-limiting toxicity. A phase II study of concurrent paclitaxel and radiation therapy is under way.

Concurrent paclitaxel and thoracic radiation for advanced non-small cell lung cancer

A phase I trial of paclitaxel therapy, administered as a weekly 3-h infusion for 6 weeks with concurrent daily thoracic radiation to patients with advanced or medically inoperable non-small cell lung cancer, was performed. Paclitaxel was escalated in increments of 10 mg/m2/week in successive cohorts of three new patients as tolerated, starting at 10 mg/m2/week. Radiation was administered to the primary tumor and regional lymph nodes (40 Gy over 4 weeks), followed by a boost to the primary tumor (20 Gy in 2 weeks). Twenty-seven patients entered this study through seven dose levels of paclitaxel ranging from 10-70 mg/m2/week for the primary purpose of evaluating the toxicity of concurrent chemoradiation treatment. Esophagitis was the principal and dose-limiting toxicity. Radiation pneumonitis occurred in two patients. Other toxicities were mild. Although not designed as an efficacy study, 23 patients were available for response, and an overall response rate of 74% (confidence interval, 65-83%) was observed.

Phase I trial of outpatient weekly paclitaxel and concurrent radiation therapy for advanced non-small-cell lung cancer

PURPOSE

To determine the maximum-tolerated dose (MTD) and dose-limiting toxicities of paclitaxel administered weekly on an outpatient basis with concurrent thoracic radiation to patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

In this phase I clinical trial, paclitaxel was administered as a 3-hour intravenous (IV) infusion, repeated every week for 6 weeks. The starting dose of paclitaxel was 10 mg/m2. Doses were escalated at 10-mg/m2 increments in successive cohorts of three new patients if tolerated. Unacceptable toxicity was defined as grade 3 nonhematologic toxicity, excluding nausea and vomiting, and grade 4 hematologic toxicity according to Cancer and Leukemia Group B expanded common toxicity criteria. Radiation was administered to the primary tumor and regional lymph nodes (40 Gy) followed by a boost to the tumor (20 Gy).

RESULTS

Twenty-seven patients were entered onto this study through seven dose escalations (from 10 mg/m2/wk to 70 mg/m2/wk for 6 weeks). Severe esophagitis occurred at 70 mg/m2 (two patients with grade 4 disease and one patient with grade 2). One of six patients at 60 mg/m2 developed grade 3 esophagitis and three of seven patients had grade 2 esophagitis. One of 27 patients developed a hypersensitivity reaction. One of 27 patients developed grade 3 neutropenia.

CONCLUSION

Esophagitis is the principle dose-limiting toxicity of weekly paclitaxel and thoracic radiation in the outpatient setting. A phase II trial using concurrent radiation and paclitaxel at the MTD of 60 mg/m2/wk is underway.

Investigation of taxol as a potential radiation sensitizer

BACKGROUND

The authors evaluated the effects of taxol, a microtubular inhibitor, as a possible radiation sensitizer on the human leukemic cell line (HL-60). Taxol acts as a mitotic inhibitor, blocking cells in the G2M-phase of the cell cycle. The differential radiation sensitivity of cells in various phases of the cell cycle has been well recognized. This study was focused on the possible interaction between radiation and a microtubular inhibitor, taxol, in regard to its ability to synchronize cells at the G2M-phase of cell cycle and, thereby, enhance the radiation sensitivity of the cells.

METHODS

HL-60 cells were exposed to 3 x 10(-8) M concentrations of taxol for 1 hour at 37 degrees C followed by reculturing for 24 hours in drug-free medium. The cells were then seeded into 60-mm diameter plastic dishes at appropriate cell concentrations to estimate their colony-forming efficiency. The radiation dose ranged from 0-400 cGy and was delivered in a single fraction. The cellular survival after treatment with the drug and/or radiation was determined using a soft agar clonogenic assay.

RESULTS

When HL-60 cells were treated with taxol, up to 70% of the cells were blocked in G2M-phase, as determined by flow cytometric analysis. At the low cytotoxic dose of 3 X 10(-8) M, the sensitizing enhancement ratio was 1.48.

CONCLUSIONS

It appears that taxol has a radiation-sensitizing effect on HL-60 cells and deserves further investigation with other cell lines.