High-resolution ellipsometric studies on fluid interfaces.

In this article, highly accurate experimental results reveal the interfacial profile between different macroscopic fluid phases. The deviation from a step profile, quantified by the ellipsometric quantity J(1), shows a strong correlation with the cohesive energy quantified by the Gordon parameter G . Surprisingly, at high values of G , J (1)( < 0) deviates significantly from any predictions. Findings for water and water-like interfaces can be interpreted in terms of the strength of hydrogen bonding at the surface.

Dynamics at the air-water interface revealed by evanescent wave light scattering.

A new tool to study surface phenomena by evanescent wave light scattering is employed for an investigation of an aqueous surface through the water phase. When the angle of incidence passes the critical angle of total internal reflection, a high and narrow scattering peak is observed. It is discussed as an enhancement of scattering at critical angle illumination. Peak width and height are affected by the interfacial profile and the focusing of the beam. In addition, the propagation of capillary waves was studied at the surface of pure water and in the presence of latex particles and amphiphilic diblock copolymers. The range of the scattering vectors where propagating surface waves were detected is by far wider than standard surface quasi-elastic light scattering (SQELS) and comparable with those of X-ray photon correlation spectroscopy (XPCS).

Observation of slow down of polystyrene nanogels diffusivities in contact with swollen polystyrene brushes.

The diffusion of dilute colloids in contact with swollen polymer brushes has been studied by evanescent wave dynamic light scattering. Two polystyrene nanogels with 16 nm and 42 nm radius were put into contact with three polystyrene brushes with varying grafting densities. Partial penetration of the nanogels within the brushes was revealed by the evanescent wave penetration depth-dependent scattering intensities. The experimental short-time diffusion coefficients of the penetrating particles were measured and found to strongly slow down as the nanoparticles get deeper into the brushes. The slow down is much more marked for the smaller (16 nm) nanogels, suggesting a size exclusion type of mechanism and the existence of a characteristic length scale present in the outer part of the brush.

On the colloidal stability of polystyrene particles prepared with surface-active initiators.

The stability of polystyrene latexes prepared with 2,2'-azobis(N-2'-methylpropanoyl-2-amino-alkyl-1)-sulphonates as surface-active initiators (inisurfs) in emulsion polymerization is investigated. The experimentally observed stability during emulsifier-free emulsion polymerization depends on the alkyl chain length of the inisurfs. The calculated barrier height of the overall interaction energy fits nicely with the experimentally observed stability during the polymerization.

High-dose chemotherapy with peripheral blood stem cell support for stage IIIB inflammatory carcinoma of the breast.

The purpose of this study was to determine outcomes for 56 patients with inflammatory breast cancer (IBC) receiving high-dose chemotherapy (HDC) with cyclophosphamide, thiotepa and carboplatin (CTCb) with peripheral blood stem cell (PBSC) support. All patients received the same total amount of chemotherapy but there were differences in the sequence of therapy: 15 received induction chemotherapy, chemotherapy mobilization of PBSC and CTCb after surgery (adjuvant group) while 41 received induction chemotherapy with (n = 17) or without (n = 24) chemotherapy for mobilization of PBSC prior to surgery and CTCb after surgery (neoadjuvant group). Median time from diagnosis to HDC was 5.5 months (range 3.5-12.5). Fifty-one patients (91%) required admission to the hospital following HDC for a median of 11 days (range 5-25). There were two (4%) infectious deaths after HDC. Twenty-four patients (43%) have relapsed at a median of 18 months (range 8-50) from diagnosis resulting in death in 34%. The probabilities of overall (OS) and event-free survival (EFS) at 3 years for all 56 patients were 0.72 and 0.53, respectively, with a median follow-up of 44 months (range 15-76) from diagnosis. There were no differences in OS, EFS or patterns of relapse between patients in the adjuvant or neoadjuvant groups. These sequences of combined modality therapy incorporating HDC are comparable or superior to other intensive approaches for the treatment of IBC. Further improvements will be necessary to decrease systemic recurrences.

Adjuvant dose-intense chemotherapy with peripheral blood stem cell support in stage II-III breast cancer with five to nine involved axillary lymph nodes.

The purpose of this study is to determine outcomes for patients with high-risk nonmetastatic breast cancer undergoing high-dose chemotherapy with peripheral blood stem cell support. Forty-three patients with stage II-III disease, five to nine positive axillary lymph nodes, and a median age of 44 years (range, 27-60 years) were enrolled in a study that included: 1) standard dose doxorubicin, 5-fluorouracil, and methotrexate adjuvant therapy; 2) cyclophosphamide, etoposide, filgrastim, and peripheral blood stem cell harvest; and 3) high-dose cyclophosphamide, thiotepa, and carboplatin (CTCb) followed by peripheral blood stem cell infusion. All 43 patients received doxorubicin, 5-fluorouracil, and methotrexate, 42 (98%) received etoposide, and 41 (95%) received CTCb. Thirty-two patients (74%) are alive, 28 (65%) without relapse at a median of 55 months (range, 41-87 months). Two died (5%) of treatment-related causes, (subclavian catheter complication after etoposide and late radiation pneumonitis), and nine other deaths (21%) were associated with recurrent breast cancer. The probabilities of overall and event-free survival at 4 years were 0.77 and 0.67, respectively, compared with 0.82 and 0.69, respectively, for 72 similar patients with 10 or more positive axillary nodes receiving the same sequence of therapy. Thus, patients with five to nine positive axillary lymph nodes have a similar risk of failure after high-dose chemotherapy and peripheral blood stem cell support as patients with 10 or more positive axillary lymph nodes.

Sequential treatment including high-dose chemotherapy with peripheral blood stem cell support in patients with high-risk stage II-III breast cancer: outpatient administration in community cancer centers.

The authors determined outcomes for patients with localized high-risk breast cancer undergoing sequential outpatient treatment with conventional-dose adjuvant therapy, chemotherapy, and growth factor mobilization of peripheral blood stem cells (PBSC) and high-dose chemotherapy (HDC) with PBSC support in community cancer centers. Ninety-six patients with stage II-IIIB noninflammatory breast cancer with 10 or more positive lymph nodes and a median age of 46 years (range, 22-60 years) were treated with: 1) doxorubicin, 5-fluorouracil, and methotrexate (AFM), four courses at 2-week intervals; 2) cyclophosphamide (4 g/m2) and etoposide (600 mg/m2) (CE), followed by filgrastim (6 microg/kg per day) and PBSC harvest; and 3) cyclophosphamide (6 g/m2), thiotepa (500 mg/m2), and carboplatin (800 mg/m2) (CTCb), followed by PBSC infusion. All 96 patients received AFM, 95 (99%) received CE, and 95 (99%) received CTCb with a median hospital stay of 12 days (5-34 days) for all phases of treatment. Sixty-nine patients (72%) are alive, 55 (57%) without relapse at a median follow-up of 53 months (range, 37-77 months). One patient (1%) died of acute myeloid leukemia and all other deaths were associated with recurrent breast cancer. The probabilities of event-free survival (EFS) at 4 years for patients with or without locally advanced disease were 0.37 and 0.69, respectively (p = 0.004), and 0.71 and 0.48 for patients who were estrogen/progesterone receptor (ER/PR) positive or ER/PR negative, respectively (p = 0.016). In multivariate analyses, locally advanced disease (relative risk, 2.3; p = 0.021) and ER/PR-negative hormone receptor status (relative risk, 2.2; p = 0.014) were the only adverse risk factors for EFS identified. Patients with zero, one, or two of these adverse risk factors had 4-year EFS of 0.80, 0.56, and 0.33, respectively. The sequential administration of AFM, CE, and CTCb followed by PBSC in an outpatient community setting was well tolerated in patients with high-risk stage II-III breast cancer. More intensive or more novel treatment strategies will be required to decrease relapses in patients who have ER/PR-negative tumors and/or have locally advanced disease.

Second attempts at mobilization of peripheral blood stem cells in patients with initial low CD34+ cell yields.

The purpose of this study was to determine the effectiveness of second mobilization strategies in patients who yielded < 2.5 x 10(6) CD34+ PBSC/kg after initial mobilization. Repeat mobilization attempts were made with chemotherapy and G-CSF (n = 61) or G-CSF alone (n = 58) in patients who failed initial mobilization with chemotherapy and G-CSF (n = 92) or G-CSF alone (n = 27). A median of 0.27 x 10(6) CD34+ cells/kg per apheresis was collected after the second mobilization, compared with 0.16 with initial harvests (p = 0.0001). Forty-eight percent achieved a target CD34+ cell dose > or = 2.5 x 10(6)/kg when harvests from the first and second mobilizations were combined. Fifteen of 17 patients (88%) with > or = 1.5 x 10(6) CD34+ cells/kg harvested after first mobilization had > or = 2.5 x 10(6) CD34+ cells/kg collected when first and second harvests were combined, as compared with 42 of 102 (41%) achieving < 1.5 x 10(6) CD34+ cells/kg with first PBSC harvests (p = 0.0001). Second mobilizations with chemotherapy and G-CSF or G-CSF alone resulted in similar CD34+ cell yields. Toxicities of second mobilizations were comparable with those of first mobilizations. Seventy-nine patients (66%) received high-dose chemotherapy with PBSC support, with recovery of neutrophils and platelets in a median of 11 and 15 days, respectively. Transplant-related mortality was 4%, and event-free survival at 2 years was 0.34. It was concluded that second mobilization attempts in patients who fail to achieve > or = 2.5 x 10(6) CD34+ cells/kg on initial mobilization were successful in 48% of patients. G-CSF alone was as effective as chemotherapy plus G-CSF in mobilizing CD34+ cells and was associated with less morbidity.

A randomized trial of two doses of cyclophosphamide with etoposide and G-CSF for mobilization of peripheral blood stem cells in 318 patients with stage II-III breast cancer.

The purpose of this study was to develop a less toxic outpatient chemotherapy regimen for mobilizing peripheral blood stem cells (PBSC). Three hundred eighteen patients with newly diagnosed stage II-III breast cancer who had received conventional dose adjuvant chemotherapy were randomized to receive intermediate-dose cyclophosphamide (2 g/m2), etoposide (600 mg/m2), and granulocyte colony-stimulating factor (G-CSF) 6 micrograms/kg/day (ID-Cy, n = 162) or high-dose cyclophosphamide (4 g/m2) and the same doses of etoposide and G-CSF (HD-Cy, n = 156) followed by collection of PBSC. Three hundred seventeen of 318 patients had apheresis performed, and 315 received high-dose chemotherapy (HDC) followed by PBSC support. The median numbers of CD34+ cells collected in a median of two apheresis following ID-Cy and HD-Cy were 19.9 and 22.2 x 10(6)/kg, respectively (p = 0.04). The fractions of patients achieving CD34+ cell doses > or = 2.5 or > or = 5.0 x 10(6)/kg were not different between the two regimens. More patients receiving HD-Cy had grade 3-4 nausea (p = 0.001), vomiting (p = 0.03), and mucositis (p = 0.04). The fractions of patients having a neutrophil nadir < 0.5 x 10(9)/L following ID-Cy and HD-Cy were 0.83 and 0.95, respectively (p = < 0.001). The fractions of patients having a platelet nadir < 25 x 10(9)/L following ID-Cy and HD-Cy were 0.13 and 0.51, respectively (p = < 0.001). More patients in the HD-Cy group received platelet (p < 0.001) and red blood cell (p < 0.001) transfusions and were admitted to the hospital more frequently (p = 0.03) than patients receiving ID-Cy. Three hundred fifteen patients received HDC followed by infusion of PBSC. There were no significant differences in the incidence of transplant-related death or early survival between patients receiving ID-Cy or HD-Cy followed by HDC. It was concluded that a regimen of Cy 2 g/m2 with etoposide and G-CSF was effective for mobilization of PBSC with low morbidity and resource utilization in patients with limited prior chemotherapy exposure.

Engraftment and outcomes of patients receiving myeloablative therapy followed by autologous peripheral blood stem cells with a low CD34+ cell content.

Engraftment kinetics after high-dose chemotherapy (HDC) were evaluated in patients receiving autologous peripheral blood stem cell (PBSC) infusions with a low CD34+ cell content. Forty-eight patients were infused with < 2.5 x 10(6) CD34+ cells/kg; 36 because of poor harvests and 12 because they electively received only a fraction of their harvested cells. A median of 2.12 x 10(6) CD34+ cells/kg (range, 1.17-2.48) were infused following one of seven different HDC regimens. All patients achieved absolute neutrophil counts > or = 0.5 x 10(9)/l at a median of day 11 (range, 9-16). Forty-seven patients achieved platelet counts > or = 20 x 10(9)/l at a median of day 14 (range, 8-250). Nine of 47 (19%) had platelet recovery after day 21, 4/47 (9%) after day 100 and one died on day 240 without platelet recovery. Twenty-six patients (54%) died of progressive disease in 51-762 days; 22 (46%) are alive at a median of 450 days (range, 94-1844), 17 (35%) of whom are surviving disease-free at a median of 494 days (range, 55-1263). No patient died as a direct consequence of low blood cell counts. These data demonstrate that PBSC products containing 1.17-2.48 x 10(6) CD34+ cells/kg resulted in relatively prompt neutrophil recovery in all patients but approximately 10% had delayed platelet recovery.

High-dose chemotherapy and peripheral blood stem cell infusion in patients with non-Hodgkin's lymphoma: results of outpatient treatment in community cancer centers.

The outcomes for patients with non-Hodgkin's lymphoma (NHL) treated with high-dose chemotherapy (HDC) and peripheral blood stem cell (PBSC) infusion by practicing oncologists in community cancer centers in the United States were determined. Eighty-three patients with NHL, who had failed conventional chemotherapy, underwent mobilization of PBSC with chemotherapy and a recombinant growth factor in an outpatient facility. At a median of 40 days (range 26-119) after mobilization chemotherapy all received carmustine (300 mg/m2 x 1), etoposide (150 mg/m2 twice a day x 4 days), cytarabine (100 mg/m2 twice a day x 4 days) and cyclophosphamide (35 mg/kg x 4 days) (BEAC) followed by infusion of unmanipulated PBSC in an outpatient facility. The probabilities of treatment-related mortality, relapse/progression, overall survival (OS) and event-free survival (EFS) at 3 years for all 83 patients were 0.07, 0.57, 0.49 and 0.38, respectively. The probabilities of relapse/progression, OS and EFS at 3 years for 28 patients who had failed primary induction chemotherapy were 0.55, 0.42 and 0.38, respectively. The probabilities of OS and EFS for 27 patients in untreated first relapse were 0.52 and 0.44, respectively, as compared to 0.56 and 0.32, respectively, for 18 patients who had reinduction attempts prior to receiving mobilization chemotherapy (P = 0.81 for OS and 0.99 for EFS). No significant risk factors for the outcomes of TRM, relapse/progression, OS or EFS could be identified. These data demonstrate that approximately 40% of patients with NHL who have failed conventional chemotherapy become long-term disease-free survivors after mobilization chemotherapy, high-dose BEAC and PBSC infusion administered in an outpatient setting in community cancer centers, with the major cause of failure being relapse. Results obtained in this study are comparable to published data in similar patient populations receiving therapy as inpatients, suggesting that clinical trials involving well-tested HDC regimens can be carried out safely in this setting.

Rapid and sustained hematopoietic reconstitution by peripheral blood stem cell infusion alone following high-dose chemotherapy.

We utilized mobilized peripheral blood stem cells (PBSC) as sole support for hematologic reconstitution following high-dose chemotherapy in 52 patients with advanced solid tumors and lymphoma. PBSC were collected by large scale leukapheresis after mobilization with chemotherapy. Each apheresis product was analysed for total nucleated cells, CFU-GM and CD34+ content. Disease-specific high-dose chemotherapy regimens were administered followed by thawed PBSC. Colony-stimulating factors were not administered. The median time to an absolute neutrophil count > 0.5 x 10(9)/l was 13 days (range 9-26 days) and median time to a sustained platelet count > 20 x 10(9)/l without transfusion support was 10 days (range 5-43 + days). There was no difference in time to recovery by dose-intensive regimen or underlying disease. The times to recover ANC and platelets both correlated significantly with increasing doses of PBSC as assayed by CD34+ cells and CFU-GM. All four patients with prolonged platelet recovery times received < 20 x 10(4) CFU-GM/kg, establishing this as a threshold value for PBSC infusion. There were no late transient or sustained graft failures. For 26 patients alive 1 year after infusion, the mean total leukocyte count is 6.3 x 10(9)/l, mean hematocrit 35.5% and mean platelet count 182 x 10(9)/l. Thirteen patients followed at least 24 months after PBSC infusion have essentially normal blood counts. Mobilized peripheral blood progenitors are an effective source of stem cells which afford rapid and complete hematopoietic engraftment after myelo-suppressive chemotherapy regimens. Engraftment appears sustained with no late failures.(ABSTRACT TRUNCATED AT 250 WORDS)

Peripheral blood stem cell mobilization by chemotherapy with and without recombinant human granulocyte colony-stimulating factor.

Chemotherapy can serve as a stimulus for mobilizing hematopoietic progenitor cells to the peripheral blood for harvest via leukapheresis. Mobilized peripheral blood stem cells (PBSC) support rapid hematologic reconstitution after bone marrow aplasia induced by intensive myelosuppressive treatments. Our purpose was to develop effective mobilization regimens allowing collection of large quantities of PBSC. We administered high-dose cyclophosphamide (HDC, 4 gm/m2) or cyclophosphamide (4 gm/m2) plus etoposide (600 mg/m2) (HDCE) in a nonrandomized, sequential fashion to 94 patients with breast cancer, lymphoma, and other malignancies with collection of PBSC via leukapheresis during white blood cell (WBC) recovery from nadir counts. Each apheresis product was analyzed for total nucleated cell number, granulocyte-macrophage colony-forming units (CFU-GM) and CD34+ cells. Twenty-four additional patients with comparable pretreatment characteristics received HDCE plus recombinant human granulocyte colony-stimulating factor (HDCE+G) after chemotherapy through the end of apheresis. Patients receiving HDC were matched for age, sex, and disease but were more heavily pretreated. HDCE was superior to HDC in mean daily CFU-GM and CD34+ yield (p < 0.05), even when groups were adjusted for performance status and amount of prior therapy. HDCE+G led to 3.7 times more CFU-GM and 4.7 times more CD34+ cells than HDCE. Target PBSC yield, defined as > 20 x 10(4) CFU-GM/kg and >4 x 10(8) cells/kg, was achieved by 92% of HDCE+G patients after a median of three aphereses, 56% of HDCE patients after five aphereses, and 16% of HDC patients after six apheresis (p < 0.0001). Prior chemotherapy inversely correlated with the quantity of PBSC harvested regardless of regimen utilized. Our results demonstrate effective chemotherapy regimens for harvesting hematopoietic progenitors in a diverse patient population. HDCE+G produced the highest number of progenitors, suggesting that increasing dose intensity and adding rhG-CSF enhances mobilization. Correlation between cumulative CD34+ and CFU-GM allows real-time flow cytometric analysis of the number of aphereses required to harvest target numbers of PBSC.

Comparative study of pamidronate disodium and etidronate disodium in the treatment of cancer-related hypercalcemia.

PURPOSE: This multicenter, double-blind, randomized trial was performed to determine the efficacy and safety of pamidronate disodium (APD) in comparison to etidronate disodium (EHDP) in the treatment of cancer-related hypercalcemia. PATIENTS AND METHODS: Sixty-five male and female adult patients with cancer and corrected calcium levels of greater than or equal to 12.0 mg/dL after 24 hours of hydration were randomized to receive either 60 mg APD given as a single 24-hour infusion or 7.5 mg/kg EHDP given as a 2-hour infusion daily for 3 days. RESULTS: APD normalized corrected calcium levels in 70% (21 of 30) of patients, whereas EHDP did so in 41% (14 of 34) of patients (P = .026). The mean corrected serum calcium level decreased from 14.6 to 10.5 mg/dL in the APD-treated group and from 13.8 to 11.6 mg/dL in the EHDP-treated group within the first week of treatment. There was no difference in response to APD in patients without versus those with bone metastases (78% v 67%). Both drugs were well tolerated. CONCLUSION: This study demonstrated that a single 60-mg infusion of APD is safe and more effective than EHDP given at the dose of 7.5 mg/kg for 3 days in the treatment of cancer-related hypercalcemia.

Continuous interleukin-2 and lymphokine-activated killer cells for advanced cancer: a National Biotherapy Study Group trial.

We conducted a multicenter, phase II trial of continuous-infusion recombinant interleukin-2 (rIL-2) and lymphokine-activated killer (LAK) cells. Patients had advanced cancer, measurable disease, and a good performance level. Treatment included a 5-day continuous infusion of 18 x 10(6) IU/m2/d of rIL-2 followed by 1 day of rest, 4 days of leukapheresis to collect cells for in vitro augmentation of cellular cytotoxicity, and 5 more days of rIL-2 infusion with reinfusion of LAK cells for 3 successive days. Therapy was repeated after 2 weeks. There were 117 patients enrolled: 63% were males, with a median age of 51 years. Eighty-two percent were managed in oncology units, and 18% were in intensive care units. Six patients died within 1 month of initiating therapy. In renal cell carcinoma, the response rate was one of 31 patients (3%), with a median survival of 10.7 months. In melanoma, the response rate was four of 33 patients (12%), with a median survival of 6.1 months. For all other histologies, response rate was three of 53 patients (5%), with a median survival of 7.4 months. All responders were asymptomatic when therapy was initiated. This trial confirms the feasibility of administering continuous rIL-2 and LAK cells outside the intensive care unit environment. Antitumor activity in melanoma was similar to that seen in multicenter trials of bolus rIL-2 and LAK cells. Activity in renal cell cancer was disappointing.

Multiple cycles of constant infusion recombinant interleukin-2 in adoptive cellular therapy of metastatic renal carcinoma.

Twenty patients were treated with metastatic renal cell cancer with 5-day cycles of constant infusion recombinant interleukin-2 (rIL-2) at 3 X 10(6) U/m2/day and with infusion of in vitro activated autologous mononuclear cells. The initial eight patients completed all rIL-2 and cellular therapy in a single 25-day treatment period. The subsequent 12 patients entered a 6-month treatment program involving two separate 15-day cycles of cellular therapy followed by four monthly cycles of maintenance rIL-2. Among eight patients in the 25-day treatment program, there were two with partial response (PR) and one with minor response (MR). None of these responses exceeded 2 months in duration. Among the 12 patients undergoing recycling of therapy, there were two with complete response (CR), two with PR, and one with MR. All four patients with CR or PR in this group demonstrated continuing response with recycling of treatment and none relapsed while receiving maintenance interleukin-2. Three remain in remission at 10, 11, and 12 months. These pilot data confirm that patients can tolerate multiple cycles of adoptive immunotherapy involving constant infusion rIL-2 and suggest that recycling of therapy is necessary to achieve clinically meaningful results.

Constant-infusion recombinant interleukin-2 in adoptive immunotherapy of advanced cancer.

Adoptive immunotherapy involving bolus-dose recombinant interleukin-2 (rIL-2) has been reported to induce tumor regression in some patients with cancer, but has been associated with severe fluid retention and cardiopulmonary stress. In an effort to preserve the efficacy but reduce the toxicity of this treatment, we used escalating doses of rIL-2 as a constant infusion rather than as a bolus dose. Forty-eight patients with advanced cancer received rIL-2 as a 24-hour infusion in five-day cycles separated by five-day periods of rest and leukapheresis. Eight patients were removed from the study before receiving cells activated in vitro. In the 40 who could be evaluated for their response, there were 13 partial responses (32.5 percent) and 2 minor responses. Partial responses were observed in Hodgkin's disease (one of one), non-Hodgkin's lymphoma (one of one), lung cancer (one of five), ovarian cancer (one of one), parotid cancer (one of two), renal cancer (three of six), and melanoma (five of ten). Responses were associated with a good performance status, a base-line lymphocyte count above 1400 per cubic millimeter, and an rIL-2-induced lymphocyte count of at least 6000. Optimal lymphocytosis required a priming dose of rIL-2 of 3 X 10(6) U per square meter of body-surface area per day, and 15 of 28 patients receiving this priming dose responded to treatment. A weight gain of more than 10 percent of total body weight (five patients) and dyspnea at rest (six patients) were unusual events restricted to patients with poorer pretreatment performance. We conclude that the administration of rIL-2 as a constant infusion may preserve the antineoplastic activity of adoptive immunotherapy while increasing the safety and comfort of patients.

Phase II trial of carboplatin in patients with advanced germ cell tumors refractory to cisplatin.

A phase II trial of carboplatin was conducted in 22 patients with advanced germ cell tumors refractory to cisplatin-based chemotherapy. Twenty of 22 patients were evaluable for toxicity and response. Two partial responses and one minor response were seen. The major toxic effect was myelosuppression. Carboplatin has antitumor activity in patients with advanced germ cell tumors refractory to cisplatin, and phase II and III studies of combination chemotherapy are indicated.