Concurrent Paclitaxel and Radiation Therapy for Solid Tumors

Cetuximab, paclitaxel, carboplatin, and radiation for head and neck cancer: a toxicity analysis

OBJECTIVE

To determine the feasibility and toxicity of the addition of cetuximab to paclitaxel, carboplatin, and concurrent radiation for patients with head and neck cancer.

MATERIALS AND METHODS

Patients with stage III or IV locally advanced squamous cell cancer of the head and neck, without distant organ metastases, were eligible. Patients received 4 weeks of induction cetuximab followed by weekly cetuximab, paclitaxel, carboplatin, and concurrent radiation.

RESULTS

Thirty-two patients were assessable for chemoradiation toxicities. Grade 3 and grade 4 mucositis occurred in 53% and 16% of patients, respectively. Grade 3 and grade 4 radiation dermatitis occurred in 44% and 9% of patients, respectively. Grade 3/4 radiation dermatitis was associated with the use of intensity modulated radiation therapy (64% vs.14%, respectively, P < 0.0001). Grade 3 and grade 4 cetuximab associated acneiform rash developed in 6% and 3% of patients. Overall 21 patients (66%) had any grade 3 toxicity and 10 patients (31%) had any grade 4 toxicity. The percentages of the intended total dose delivered of carboplatin, cetuximab, paclitaxel, and radiation were 86%, 89%, 89%, and 96%, respectively.

CONCLUSION

Cetuximab, when combined with paclitaxel, carboplatin and intensity modulated radiation therapy, increases dermatologic toxicity but does not increase mucosal toxicity as compared with previous Brown University Oncology Group studies of paclitaxel, carboplatin, and conventional radiation for patients with head and neck cancer.

Paclitaxel poliglumex (PPX-Xyotax) and concurrent radiation for esophageal and gastric cancer: a phase I study

OBJECTIVES

To determine the maximal tolerated dose (MTD) and dose limiting toxicities of poly(l-glutamic acid)-paclitaxel (PPX) and concurrent radiation (PPX/RT) for patients with esophageal and gastric cancer.

METHODS

Patients with esophageal or gastric cancer receiving chemoradiation for loco-regional, adjuvant, or palliative intent were eligible. The initial dose of PPX was 40 mg/m2/wk, for 6 weeks with 50.4 Gy radiation. Dose levels were increased in increments of 10 mg/m2/wk of PPX.

RESULTS

Twenty-one patients were enrolled over 5 dose levels. Sixteen patients had esophageal cancer and 5 had gastric cancer. Twelve patients received PPX/RT as definitive loco-regional therapy, 4 patients had undergone resection and received adjuvant PPX/RT, and 5 patients had metastatic disease and received PPX/RT for palliation of dysphagia. Dose limiting toxicities of gastritis, esophagitis, neutropenia, and dehydration developed in 3 of 4 patients treated at the 80 mg/m2 dose level. Four of 12 patients (33%) with loco-regional disease had a complete clinical response.

CONCLUSIONS

The maximally tolerated dose of PPX with concurrent radiotherapy is 70 mg/m2/wk for patients with esophageal and gastric cancer.

High-dose radioimmunotherapy combined with fixed, low-dose paclitaxel in metastatic prostate and breast cancer by using a MUC-1 monoclonal antibody, m170, linked to indium-111/yttrium-90 via a cathepsin cleavable linker with cyclosporine to prevent human anti-mouse antibody

PURPOSE

Although radioimmunotherapy alone is effective in lymphoma, its application to solid tumors will likely require a combined modality approach. In these phase I studies, paclitaxel was combined with radioimmunotherapy in patients with metastatic hormone-refractory prostate cancer or advanced breast cancer.

EXPERIMENTAL DESIGN

Patients were imaged with indium-111 (111In)-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-peptide-m170. One week later, yttrium-90 (90Y)-m170 was infused (12 mCi/m2 for prostate cancer and 22 mCi/m2 for breast cancer). Initial cohorts received radioimmunotherapy alone. Subsequent cohorts received radioimmunotherapy followed 48 hours later by paclitaxel (75 mg/m2). Cyclosporine was given to prevent development of human anti-mouse antibody.

RESULTS

Bone and soft tissue metastases were targeted by 111In-m170 in 15 of the 16 patients imaged. Three prostate cancer patients treated with radioimmunotherapy alone had no grade 3 or 4 toxicity. With radioimmunotherapy and paclitaxel, two of three prostate cancer patients developed transient grade 4 neutropenia. Four breast cancer patients treated with radioimmunotherapy alone had grade 3 or 4 myelosuppression. With radioimmunotherapy and paclitaxel, both breast cancer patients developed grade 4 neutropenia. Three breast cancer patients required infusion of previously harvested peripheral blood stem cells because of neutropenic fever or bleeding. One patient in this trial developed human anti-mouse antibody in contrast to 12 of 17 patients in a prior trial using m170-radioimmunotherapy without cyclosporine.

CONCLUSIONS

111In/90Y-m170 targets prostate and breast cancer and can be combined with paclitaxel with toxicity limited to marrow suppression at the dose levels above. The maximum tolerated dose of radioimmunotherapy and fixed-dose paclitaxel with peripheral blood stem cell support has not been reached. Cyclosporine is effective in preventing human anti-mouse antibody, suggesting the feasibility of multidose, "fractionated" therapy that could enhance clinical response.

Basic characterization of 64Cu-ATSM as a radiotherapy agent

64Cu-diacetyl-bis(N4-methylthiosemicarbazone) (64Cu-ATSM) is a promising radiotherapy agent for the treatment of hypoxic tumors. In an attempt to elucidate the radiobiological basis of 64Cu-ATSM radiotherapy, we have investigated the cellular response patterns in vitro cell line models. Cells were incubated with 64Cu-ATSM, and the dose-response curves were obtained by performing a clonogenic survival assay. Radiation-induced damage in DNA was evaluated using the alkali comet assay and apoptotic cells were detected using Annexin V-FITC and propidium iodide staining methods. Washout rate and subcellular distribution of 64Cu in cells were investigated to further assess the effectiveness of 64Cu-ATSM therapy on a molecular basis. A direct comparison of subcellular localization of Cu-ATSM was made with the flow tracer analog Cu-pyruvladehyde-bis(N4-methylthiosemicarbazone). In this study, 64Cu-ATSM was shown to reduce the clonogenic survival rate of tumor cells in a dose-dependent manner. Under hypoxic conditions, cells took up 64Cu-ATSM and radioactive 64Cu was highly accumulated in the cells. In the 64Cu-ATSM-treated cells, DNA damage by the radiation emitted from 64Cu was detected, and inhibition of cell proliferation and induction of apoptosis was observed at 24 and 36 h after the treatment. The typical features of postmitotic apoptosis induced by radiation were observed following 64Cu-ATSM treatment. The majority of the 64Cu taken up into the cells remained in the postmitochondrial supernatant (the cellular residue after removal of the nuclei and mitochondria), which indicates that the beta- particle emitted from 64Cu may be as effective as the Auger electrons in 64Cu-ATSM therapy. These data allow us to postulate that 64Cu-ATSM will be able to attack the hypoxic tumor cells directly, as well as potentially affecting the peripheral nonhypoxic regions indirectly by the beta- particle decay of 64Cu.

Paclitaxel and concurrent radiation in upper gastrointestinal cancers

Effective locoregional treatments are needed for adenocarcinomas of the esophagus, stomach, and pancreas. Paclitaxel has been investigated as a radiation sensitizer for upper gastrointestinal malignancies. In esophageal cancer, the combination of low-dose weekly paclitaxel, platinum, and concurrent radiation therapy (RT) has substantial activity and is well tolerated. Regimens that add fluorouracil (5-FU) to paclitaxel and platinum or incorporate hyperfractionation radiation have a higher incidence of severe esophagitis. In gastric cancer, adjuvant concurrent paclitaxel, 5-FU, and radiation is being investigated in the cooperative group setting. In pancreatic cancer, paclitaxel may be a radiation sensitizer even to tumor cells that are resistant to paclitaxel as a single agent. The Radiation Therapy Oncology Group (RTOG) demonstrated a 43% 1-year survival with paclitaxel/RT for patients with locally advanced pancreatic cancer. This represented a 40% improvement in survival compared to the previous RTOG 92-09 study of 5-FU-based chemoradiation. Ongoing trials in pancreatic cancer are investigating the addition of gemcitabine to paclitaxel and radiation and incorporating molecular targeting agents.

Comparison of antiangiogenic activities using paclitaxel (taxol) and docetaxel (taxotere)

Tumor growth requires a competent vascular supply and angiogenesis has been considered as a potential target for the treatment of several cancers. The two clinically approved taxanes, paclitaxel and docetaxel, are novel antimitotic agents that are under extensive investigation in clinical trials. Both taxanes have demonstrated significant activity against many solid tumors, but little is known about the effect of paclitaxel and docetaxel on endothelial cell function and angiogenic processes. The purpose of our study was to examine and compare the effects of these drugs on angiogenic processes in vitro and in vivo. These processes include: proliferation, migration and differentiation of cultured human umbilical vein endothelial cells (HUVEC) (in vitro), capillary sprouting of rat aortic ring explants (ex vivo) and HT1080 tumor growth in vivo. Our results demonstrate that endothelial cells are 10-100-fold more sensitive to these drugs than tumor cells. Additionally, comparison of the taxanes demonstrated that angiogenesis is blocked by both drugs primarily via inhibition of proliferation and differentiation (tube assay) and induction of cell death. Docetaxel, however, appears to be more potent at inhibiting angiogenesis, with an IC(50) concentration 10x less than that of paclitaxel. We conclude that these important findings should be taken in account in clinical trials where tumor angiogenesis is being targeted.

Development of an in vitro chemo-radiation response assay for cervical carcinoma

PURPOSE

To determine if synergistic effects of radiation (RT) and chemotherapy (chemo) on human cervical carcinoma cell lines and fresh tumor explants could be determined using an in vitro assay.

EXPERIMENTAL DESIGN

In vitro radiation response was determined for 4 cell lines and 26 fresh tumor explants in an agar-based assay. Cells were exposed to increasing doses of RT with or without cisplatin (CDDP), carmustine (BCNU), buthionine sulfoximine (BSO), or paclitaxel (Tax). Cell suspensions were cultured for 5 days, with [(3)H]thymidine added on day 3 and proliferation was measured. Results were reported as the fraction of proliferation compared to control (FC). For each combination of irradiation and drug, synergy was tested using the Chou analysis, where a combination index (CI) <1 indicated synergistic interaction. In simple correlation analysis, an R value of >0.7 indicated cross-resistance.

RESULTS

RT dose-dependent proliferation inhibition was observed for 2 of the 4 cell lines, and for all but 1 of the fresh specimens. Significant heterogeneity of tumor response to RT was seen. Four specimens that were 1 standard deviation below the median FC response after exposure to 300 cGy were classified as extremely radiation resistant. Twenty-one tumors were evaluated for synergistic response using the combination of chemo and RT with a median FC of 0.27 (+/-0.27) for 6.0 Gy of RT alone, 0.22 (+/-0.21) for CDDP alone, and 0.05 (+/-0.08) for the combination. A CI of 0.35 and an R value of 0.09 demonstrated synergy between chemo and RT without cross-resistance. Similar synergy without cross-resistance was found for RT in combination with BCNU, BSO, and TAX.

CONCLUSIONS

Heterogeneous RT dose-response relationships in the in vitro assay were demonstrated. Explants were more sensitive to RT than cell lines. Unlike cell lines, fresh tumor cells consistently displayed synergy with RT and chemo. The synergy between RT and BSO suggests that glutathione depletion may enhance the effect of RT. The assay was feasible for examining fresh tumors and may be an important tool for studying RT or drug resistance. Clinical trials to evaluate this assay are indicated.

Combined modality radioimmunotherapy. Promise and peril

BACKGROUND

Single-agent radioimmunotherapy (RIT), although potentially useful for slowing solid tumor growth, has not been effective in curing aggressive tumors, such as breast cancer. These cancers typically have p53 mutations and are less susceptible to apoptosis, the apparent mechanism of cell death from low dose-rate radiation. Thus, synergistic or combined modality radioimmunotherapy (CMRIT) agents are needed to increase radiosensitivity for therapeutic enhancement without additive toxicity.

METHODS

To assess synergy in CMRIT in a breast cancer xenograft model, we evaluated RGD peptide EMD 121974, an inhibitor of alpha(v)beta(3) integrin; paclitaxel, an antimicrotubule; IMC-C225, a monoclonal antibody to epidermal growth factor receptor (EGFR); and bcl-2 antisense oligonucleotide G3139. Groups of mice received (90)Y-DOTA-ChL6 in combination with each agent. Tumor size, survival, and blood counts were monitored for efficacy and toxicity. Immunopathologic evaluation of apoptosis was performed at selected time points after RIT and RIT + RGD CMRIT.

RESULTS

CMRIT with RGD peptide increased apoptosis and resulted in 57% cures, compared with 0% cures with RIT alone. CMRIT with paclitaxel after RIT increased cures to 88%, compared with 25% cures with RIT before paclitaxel administration. CMRIT with IMC-C225 resulted in up to 20% cures if given before RIT. A time-dependent increase in toxicity was observed with IMC-C225 after RIT. CMRIT with bcl-2 antisense G3139 resulted in no cures and an increased rate of regrowth compared with RIT alone.

CONCLUSIONS

Some combined modality therapies resulted in higher numbers of cures, while others decreased cures and responses and increased toxicity compared with RIT alone. These results support the potential for CMRIT but illustrate the complexity of predicting the efficacy and toxicity and the importance of the relationship between dose and sequence of administration.

Combined modality radioimmunotherapy for human prostate cancer xenografts with taxanes and 90yttrium-DOTA-peptide-ChL6

BACKGROUND

Therapy for prostate cancer in the PC3 tumor-nude mouse model with 90yttrium-(90Y)-DOTA-peptide-ChL6 (5.55 MBq;150 microCi) has resulted in durable responses. To make radioimmunotherapy (RIT) more effective, the radiation-enhancing drugs Taxol (paclitaxel) and Taxotere (docetaxel) were tested for synergy with 90Y-DOTA-peptide-ChL6.

METHODS

Nude mice bearing human prostate cancer PC3 xenografts were treated with 90Y-DOTA-peptide-ChL6 (2.78 MBq; 75 microCi) and after 24 hr, paclitaxel (300 or 600 microg), or docetaxel (300 microg). Tumor size, survival, blood counts, and pharmacokinetics were monitored to assess efficacy and toxicity.

RESULTS

Docetaxel plus RIT had a 67% cure rate, whereas no mice were cured among the RIT alone, chemotherapy alone, or untreated controls. Paclitaxel (600 microg) plus RIT produced a 100% response rate with 20% cures. Average tumor volume was reduced to a greater degree in the combined modality radioimmunotherapy (CMRIT) groups compared to controls and the anti-tumor response was durable. Myelotoxicity in the combined modality groups (RIT plus paclitaxel or RIT plus docetaxel) were similar to groups receiving the same dose of RIT alone.

CONCLUSION

In the PC3-tumor nude mouse model, addition of paclitaxel or docetaxel to 90Y-DOTA-peptide-ChL6, in doses clinically achievable in humans, provided therapeutic synergy without increased or excessive toxicity.

Intraperitoneal radioimmunochemotherapy of ovarian cancer: a phase I study

A phase I trial was designed to examine the feasibility of combining interferon and Taxol with intraperitoneal radioimmunotherapy (177Lu-CC49). Patients with recurrent or persistent ovarian cancer confined to the abdominal cavity after first line therapy, Karnofsky performance status > 60, adequate liver, renal and hematologic function, and tumor that reacted with CC49 antibody were enrolled. Human recombinant alpha interferon (IFN) was administered as 4 subcutaneous injections of 3 x 10(6) U on alternate days beginning 5 days before RIT to increase the expression of the tumor-associated antigen, TAG-72. The addition of IFN increased hematologic toxicity such that the maximum tolerated dose (MTD) of the combination was 40 mCi/m2 compared to 177Lu-CC49 alone (45 mCi/m2). Taxol, which has radiosensitizing effects as well as antitumor activity against ovarian cancer, was given intraperitoneally (i.p.) 48 hrs before RIT. It was initiated at 25 mg/m2 and escalated at 25 mg/m2 increments to 100 mg/m2. Subsequent groups of patients were treated with IFN + 100 mg/m2 Taxol + escalating doses of 177Lu-CC49. Three or more patients were treated in each dose group and 34 patients were treated with the 3-agent combination. Therapy was well tolerated with the expected reversible hematologic toxicity. The MTD for 177Lu-CC49 was 40 mCi/m2 when given with IFN + 100 mg/m2 Taxol. Interferon increased the effective whole body half-time of radioactivity and the whole body radiation dose. Taxol did not have a significant effect on pharmacokinetic or dosimetry parameters. Four of 17 patients with CT measurable disease had a partial response (PR) and 4 of 27 patients with non-measurable disease have progression-free intervals of 18+, 21+, 21+, and 37+ months. The combination of intraperitoneal Taxol chemotherapy (100 mg/m2) with RIT using 177Lu-CC49 and interferon was well tolerated, with bone marrow suppression as the dose-limiting toxicity.

Status of radioimmunotherapy in the new millennium

This synopsis attempts to summarize progress made in radioimmunotherapy (RIT) by the end of the 20th century addressing the problems, possible solutions, and recent developments. The reduction of minimal residual disease in an adjuvant setting appears to be a feasible goal for RIT utilizing short-range alpha-emitters. RIT has been more successful in the radiosensitive hematologic malignancies, for example lymphomas and leukemias as compared with small solid tumors. Several radiopharmaceuticals seem near approval for RIT in patients with non-Hodgkin's lymphoma (NHL) as therapeutic responses, including complete responses, are common. Obstacles to successful RIT have been recognized and strategies to overcome these hurdles and to improve efficacy are continuously being developed resulting in encouraging outcome particularly with locoregional routes of administration in solid tumors. Systemic RIT for solid tumors will need manipulating the tumor-host to improve the tumor uptake and retention of radioimmunoconjugates (RICs). The utilization of radiometals, stable chelators, biodegradable linkers and bone marrow transplantation should be able to deliver the radiation dose required for successful treatment. In conjunction with additional synergistic agents, RIT is likely to have a great impact on the treatment of solid tumors. The ability to generate new constructs, such as bivalent antibodies or fusion proteins incorporating two different functional proteins opens exciting opportunities for new therapeutic modalities. These developments will hopefully offset the impediments to the successful use of RIT.

Combined modality radioimmunotherapy with Taxol and 90Y-Lym-1 for Raji lymphoma xenografts

Despite effective therapies for non-Hodgkin's lymphoma (NHL), the majority of patients are not cured. Radioimmunotherapy (RIT) has shown good results in preclinical and clinical trials even in patients that are non-responsive to standard chemotherapy. To make RIT more effective, agents such as paclitaxel (Taxol), that can enhance radiation effects, are being tested. Nude mice bearing human Burkitt's lymphoma (Raji) xenografts were treated with: 1) 150 or 200 microCi (5.5 or 7.3 MBq) of 90Y-2IT-BAD-Lym-1 alone, 2) 600 micrograms of Taxol alone, 3) 150 or 200 microCi of 90Y-2IT-BAD-Lym-1 plus 600 micrograms of Taxol given 24 hours after RIT, or 4) no treatment. Tumor size, survival, mouse weight and blood counts were monitored to assess efficacy and toxicity. Survival for mice treated in this 84 day trial was: 71% for 90Y-2IT-BAD-Lym-1 (200 microCi) plus Taxol, 29% for Taxol alone, 6% for 90Y-2IT-BAD-Lym-1 (200 microCi) alone and 14% in the untreated group. Average tumor volume in the 90Y-2IT-BAD-Lym-1 (200 microCi) plus Taxol group was reduced by 89 and 99% compared to the RIT alone and Taxol alone groups, respectively. Mice treated with 150 microCi had less toxicity than those treated with 200 microCi of 90Y-2IT-BAD-Lym-1, however, the higher radiation dose, and Taxol, were required for improved survival. Mouse weights and myelotoxicity in the combined modality (RIT plus Taxol) groups were similar to those receiving the same dose of RIT alone. In the Raji tumored nude mouse model, addition of Taxol to 90Y-2IT-BAD-Lym-1, in doses clinically achievable in humans, provided therapeutic synergy without increased or excessive toxicity.