Phase I Study of Paclitaxel Given by Seven-Week Continuous Infusion Concurrent with Radiation Therapy for Locally Advanced Non???Small Cell Lung Cancer:

Microtubule stabilising agents and ionising radiation: multiple exploitable mechanisms for combined treatment

Combined radiochemotherapy treatment modalities are in use for many indications and therefore of high interest. Even though a combined modality in clinical use is often driven by pragmatic aspects, mechanistic preclinical-based concepts of interaction are of importance in order to translate and implement an optimal combination and scheduling of two modalities into the clinics. The use of microtubule stabilising agents is a promising strategy for anti-cancer therapy as a part of combined treatment modality with ionising radiation. Traditionally, microtubule targeting agents are classified as cytotoxic chemotherapeutics and are mostly used in a maximally tolerated dose regimen. Apart from direct cytotoxicity and similar to mechanisms of molecular targeting agents, microtubule stabilising agents interfere with multiple cellular processes, which can be exploited as part of combined treatment modalities. Recent preclinical investigations on the combination of ionising radiation and microtubule stabilising agents reveal new mechanistic interactions on the cellular and tumour level and elucidate the supra-additive tumour response observed particularly in vivo. The major focus on the mechanism of interaction was primarily based on radiosensitisation due to cell cycle arrest in the most radiosensitive G2/M-phase of the cell cycle. However, other mechanisms of interaction such as reoxygenation and direct as well as indirect endothelial damage have also been identified. In this review we summarise and allocate additive and synergistic effects induced by the combined treatment of clinically relevant microtubule stabilising agents and ionising radiation along a described radiobiological framework encompassing distinct mechanisms relevant for exploiting the combination of drugs and ionising radiation.

How to improve loco-regional control in stages IIIa-b NSCLC? Results of a three-armed randomized trial from the Swedish Lung Cancer Study Group

BACKGROUND

A combination of chemotherapy and radiotherapy is the treatment base for locally advanced non-small cell lung cancer (NSCLC). However, both loco-regional and distant failure is frequent. Attempts to improve the loco-regional control were made in three separate phase II studies in Swedish University Hospitals, where accelerated radiotherapy or concurrent daily or weekly chemotherapy with conventional radiotherapy were tested. Comparatively good results from these studies lead to this national randomized phase II study, the RAKET-study, where the different concepts were investigated on a wider basis for further phase III studies.

METHODS

Inoperable stage III non-small cell lung cancer patients in good performance status (PS<2) were equally randomized to either of three arms in eight institutions. All arms started with two cycles of induction chemotherapy: paclitaxel 200 mg/m2 and carboplatin AUC6. Arm A: a third identical cycle was given concomitant with start of accelerated radiotherapy, 1.7 Gy BID to 64.6 Gy in 4.5 weeks. Arm B consisted of daily concomitant paclitaxel 12 mg/m2 with conventionally fractionated radiotherapy: 2 Gy to 60 Gy in 6 weeks. Arm C: weekly concomitant paclitaxel 60 mg/m2 and identical radiotherapy to 60 Gy. Primary endpoint: TTP. Secondary: OS, toxicity, QL and relapse pattern.

RESULTS

Between June 2002 and May 2005 152 patients were randomized and of them 151 were evaluable: 78 men and 73 women, median age 62 years (43-78), 55% had performance status 0 and 45% PS 1. Thirty-four percent had stage IIIa and 66% IIIb.

HISTOLOGY

adenocarcinoma 48%, squamous cell carcinoma 32% and 20% non-small cell carcinoma. The three arms were well balanced. Toxicity was manageable with 12% grades 3-4 esophagitis, 1% grades 3-4 pneumonitis and there was no clear difference between the arms. The QL data did not differ either. Median time to progression was 9.8 (8.3-12.7) months (8.8, 10.3 and 9.3 months for arms A, B and C, respectively). Median survival was 17.8 (14.4-23.7) months (17.7, 17.7 and 20.6 months for A, B and C, respectively). The 1-, 3- and 5-year overall survival was 63, 31 and 24%. Sixty-nine percent of the patients relapsed with distant metastases initially and 31% had loco-regional tumor progression, without significant differences between treatment arms. Thirty-four percent developed brain metastases.

CONCLUSIONS

Treatment results are quite equal by intensifying the loco-regional treatment either by accelerated fractionated radiotherapy or daily or weekly concomitant chemo-radiotherapy both in terms of survival, toxicity and quality of life. The optimal treatment schedule for patients with locally advanced NSCLC is still to be decided and investigated in future clinical studies. Relapse pattern with distant metastases and especially brain metastases is a great problem and need further research for better therapy options and higher cure rate for this patient group.

Phase I study to determine the MTD of paclitaxel given three times per week during concurrent radiation therapy for stage III non-small cell lung cancer

OBJECTIVE

To evaluate the toxicity and the maximum tolerated dose (MTD) of paclitaxel concurrently with three-dimensional (3D) conformal radiotherapy for patients with locally advanced non-small cell lung cancer (LANSCLC) after 2-3 cycles of induction chemotherapy.

RESEARCH DESIGN AND METHODS

Patients with histologically proven stage III non-small cell lung cancer (NSCLC) were eligible. Induction chemotherapy regimen included cisplatin (40 mg/m2) on days 1 and 2, and vinorelbine (25 mg/m2) on days 1 and 8 every 3 weeks for 2 or 3 cycles, followed a month later by continual three-dimensional (3D) conformal radiotherapy (60 Gy in 30 fractions for 6 weeks) delivered concurrently with paclitaxel dose escalating from the lowest level, 15 mg/m2, twice weekly, 6 weeks in all, to the highest level, 15 mg/m2, three times a week, 6 weeks in all.

MAIN OUTCOME MEASURES

The MTD was defined as the highest safely tolerated dose at which no more than one patient out of six experiences dose-limiting toxicity, with the next higher dose having at least two out of six patients experience dose-limiting toxicity (DLT).

RESULTS

Twenty-three patients were enrolled in this study. The maximum tolerated dose of paclitaxel during 3D-conformal radiotherapy was not reached at 15 mg/m2, three times a week, 6 weeks in all, a level which has been recommended for Caucasian patients with LANSCLC without induction chemotherapy. The overall response rate of induction chemotherapy alone was 47.8% (0% complete remission, 47.8% partial remission, 39.1% stable disease, 13% progressive disease) and that of induction chemotherapy plus concurrent treatment was 78.3% (18/23), including 8.7% (2/23) complete remissions. None of the patients died as a result of toxicity. The median survival time was 23.0 months.

CONCLUSIONS

15 mg/m2 of paclitaxel, three times a week, concurrently with 3D-conformal radiotherapy for patients with locally advanced NSCLC after 2 or 3 cycles of induction chemotherapy is a safe and effective dose, according to our preliminary study.