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Vascular endothelial growth factor, fibroblast growth factor (FGF), and platelet-derived growth factor (PDGF) and their cognate receptor tyrosine kinases are strongly implicated in angiogenesis associated with solid tumors. Using rational drug design coupled with traditional screening technologies, we have discovered SU6668, a novel inhibitor of these receptors. Biochemical kinetic studies using isolated Flk-1, FGF receptor 1, and PDGF receptor beta kinases revealed that SU6668 has competitive inhibitory properties with respect to ATP. Cocrystallographic studies of SU6668 in the catalytic domain of FGF receptor 1 substantiated the adenine mimetic properties of its oxindole core. Molecular modeling of SU6668 in the ATP binding pockets of the FIk-1/KDR and PDGF receptor kinases provided insight to explain the relative potency and selectivity of SU6668 for these receptors. In cellular systems, SU6668 inhibited receptor tyrosine phosphorylation and mitogenesis after stimulation of cells by appropriate ligands. Oral or i.p. administration of SU6668 in athymic mice resulted in significant growth inhibition of a diverse panel of human tumor xenografts of glioma, melanoma, lung, colon, ovarian, and epidermoid origin. Furthermore, intravital multifluorescence videomicroscopy of C6 glioma xenografts in the dorsal skinfold chamber model revealed that SU6668 treatment suppressed tumor angiogenesis. Finally, SU6668 treatment induced striking regression of large established human tumor xenografts. Investigations of SU6668 activity in cancer patients are ongoing in Phase I clinical trials.

A series of new 3-substituted indolin-2-ones containing a tetrahydroindole moiety was developed as specific inhibitors of receptor tyrosine kinases associated with VEGF-R, FGF-R, and PDGF-R growth factor receptors. These compounds were evaluated for their inhibitory properties toward VEGF-R2 (Flk-1/KDR), FGF-R1, PDGF-Rbeta, p60(c)()(-)()(Src)(), and EGF-R tyrosine kinases and their ability to inhibit growth factor-dependent cell proliferation. Structure-activity relationships of this new pharmacophore have been determined at the level of kinase inhibition. Compounds containing a propionic acid moiety at the C-3' position of the tetrahydroindole ring represented the most potent indolin-2-ones to inactivate the VEGF, FGF, and PDGF receptor kinases. The inhibitory activities of 9d against VEGF-R2 (Flk-1), 9h against FGF-R1, and 9b against PDGF-Rbeta were 4, 80, and 4 nM, respectively. However, all of these compounds were inactive when tested against the EGF-R tyrosine kinase. Compounds 9a and 9b represented the most potent inhibitors of these classes to inhibit both biochemical kinase and growth factor-dependent cell proliferation for these three targets. In addition, compound 9a was cocrystallized with the catalytic domain of FGF-R1 providing evidence to explain the structure-activity relationship results. This study has provided evidence to support the potential of these new tyrosine kinase inhibitors for the treatment of angiogenesis and other growth factor-related diseases including human cancers.

We have characterized the expression and activity of the cell cycle regulatory machinery and the organization of the cytoskeleton of the p16(Ink4a)-deficient astrocytoma cell line, U343 MG-a (U343), following retinoic acid (RA) treatment. RA causes cell cycle arrest at low cell density and significant morphological changes in U343 cells, reflected by reorganization of the intermediate filament, GFAP, and actin. RA-induced cell cycle arrest is also associated with induction of p27Kip1 expression, inhibition of cdk2-associated kinase activity and alteration of the phosphorylation state of the pRB-family proteins. We next determined the effect of inducing expression of the cyclin dependent kinase inhibitors (CKI's), p16(Ink4a), p21Cip1/Waf1 or p27Kip1 on the proliferation and morphology of these malignant astrocytoma cells in the absence and presence of RA. Induction of p16, p21 or p27, using the tetracycline repressor system, potently inhibits proliferation of U343 cells. However, rather than resembling RA-treated cells, CKI-induced U343 cells become flat with abundant cytoplasm and perinuclear vacuolization. CKI-induced morphological alterations are accompanied by a significant reorganization of glial filaments within the cytoplasm. Interestingly, when U343 cells are growth arrested by p16, p21 or p27 induction and treated simultaneously with RA, a dramatic morphological change occurs, cells acquiring multiple long, tapering processes reminiscent of primary astrocytes. This rearrangement is accompanied by reorganization of GFAP, vimentin and actin. Vimentin specifically relocalizes to the tips of the long processes which form. The arrangement of intermediate filaments in these cells is, in fact, indistinguishable from their arrangement in primary human astrocytes. These data demonstrate that when a strong proliferative block, produced by CKI expression, occurs in conjunction with the morphogenic signals generated by RA, these p16-deficient malignant astrocytoma cells are induced to phenotypically resemble normal astrocytes.

A new treatment program was developed in an attempt to increase the complete remission rate and survival of previously untreated patients with advanced stages of diffuse aggressive lymphomas. A flexible number of cycles of ProMACE chemotherapy (prednisone, methotrexate, doxorubicin, cyclophosphamide, and epipodophyllotoxin VP-16) was alternated with a flexible number of cycles of MOPP chemotherapy (mechlorethamine, vincristine sulfate, procarbazine, and prednisone), and finally late intensification with ProMACE therapy was given. The duration of each phase of treatment was determined by the patient's rate of tumor response. Complete remissions were achieved in 55 of 74 patients (74%) with a median duration of follow-up exceeding 2 1/2 years. Only ten of the complete responders (18%) have had relapse. The dose-limiting toxicity is myelosuppression, and eight patients (10%) died from sepsis. Median survival for all patients has not been reached but is predicted to exceed 4 years with 65% of patients alive at 4 years. Previously we achieved a 46% complete remission rate with 38% of all patients alive at 4 years; relapse-free survival beyond 2 years was tantamount to cure. Therefore, ProMACE-MOPP chemotherapy represents a substantial improvement in treating patients with diffuse aggressive lymphomas.

The National Cancer Institute since 1955 has been charged with responsibility for discovering new anti-cancer agents and bringing them to clinical trial. These activities are carried out by NCI's Developmental Therapeutics Program, which has established systems for discovery, experimental testing, bulk synthesis, formulation, and toxicological testing of candidate drugs, and by the Cancer Therapy Evaluation Program, which conducts initial trials to establish safe doses of new agents and to determine their utility in treating specific forms of cancer. These clinical trials are conducted both at NCI in Bethesda, Md., and at selected cancer centers throughout the United States. This paper describes the safeguards that NCI has built into the clinical trials system in the past decade-safeguards that ensure the safety of patients and the accuracy of data collected and at the same time allow efficient testing of each promising new agent in the fight against cancer. Recent improvements in cancer survival leave little doubt that patients are indeed benefiting from extensive efforts to discover and develop new drugs for cancer treatment.

Twenty-seven women previously treated with MOPP (mechlorethamine, vincristine, procarbazine, prednisone) chemotherapy were evaluated to determine the status of ovarian function. All patients had completed therapy a median of nine years earlier and had a median age of 30 years at the time of evaluation. Persistent amenorrhea has occurred in 11 of 24 patients (46 percent) treated with MOPP alone or MOPP plus radiation excluding the pelvis. Of patients with amenorrhea, 89 percent were older than age 25 at the time of treatment. In contrast, 80 percent of patients younger than age 25 at treatment continue to menstruate regularly. The time from diagnosis to amenorrhea was significantly shorter in the older patients (p = 0.001). Evaluation of serum gonadotropin and estradiol levels confirms ovarian failure as the cause of amenorrhea in all patients. Overall, these 27 patients have borne 13 normal children subsequent to chemotherapy. This long-term follow-up study demonstrates that chemotherapy-induced ovarian failure is age-related, that ovarian failure is often gradual in onset following the completion of chemotherapy and that, to date, the children born of women treated with this chemotherapy regimen appear to be entirely normal.

The currently accepted therapies for ovarian cancer have produced only limited numbers of extended complete remissions in advanced-stage disease. Studies of high-volume intraperitoneal chemotherapy have been initiated to define the toxicology, pharmacokinetics, and the therapeutic effectiveness of this treatment modality. This technique has been virtually ignored until recently, because little success has been achieved with it except in one study (Rutledge, 1966), in which large intraperitoneal fluid volumes were used. The general lack of success probably reflects inadequate attention to physiologic and pharmacologic principles of drug distribution and absorption in a space as large as the peritoneal cavity. Biomedical engineers, pharmacologists, and clinicians at the NCI have cooperated in the development of a rational chemotherapy for ovarian cancer. Following mathematical pharmacokinetic modeling and toxicologic studies in rat, a Phase I clinical trial of intraperitoneal methotrexate administered in large volumes of dialysis fluid was initiated. Results in three patients confirm the practicality of this approach, and further investigation is warranted.

A search for improved forms of systemic chemotherapy in advanced ovarian carcinoma has resulted in two prospective trials at the Medicine Branch National Cancer Institute. The first trial compared high-dose, split-course intravenous cyclophosphamide with conventional treatment with an oral alkylating agent, melphalan [also called L-phenylalanine mustard (PAM)]. While both regimens were essentially equal in therapeutic efficacy, the former was considerably more toxic and the latter was therefore preferred. The second trial employed a 4-drug combination (5-fluorouracil, methotrexate, cyclophosphamide, and hexamethylmelamine); the results indicated a higher overall response rate (85%) and a higher complete remission rate (31%) with the combination therapy than with the PAM therapy, although the study is short and the observations are preliminary.

One hundred sixty-one patients with advanced Hodgkin's disease achieved complete remission after combination chemotherapy. Of these, 52 (32%) have subsequently relapsed and the patterns of relapse have been studied. The probability of relapse increases with increasing stage and particularly with the presence of systemic symptoms. Patients with Nodular Sclerosis histology are more likely to relapse than those with other histologies. Patients relapse primarily (92%) in sites of previous disease and particularly in nodal sites (75%). Nodal sites most frequently involved at relapse are the central nodal areas and the left supraclavicular area. When patients relapse in new sites they tend to be either adjacent to sites of previous disease which relapse or to be contiguous with previously involved sites of disease. In the small number of patients who received prophylactic radiation therapy to sites of nodal disease after complete remission, the pattern of relapse was not significantly altered.

The results of treatment of 198 patients with Hodgkin's disease with MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) were analyzed. Eighty percent attained complete remission, and 68% of patients achieving a complete remission have remained disease free beyond 10 years from the end of treatment. Results of autopsy on patients who died of other causes while in clinical complete remission did not show evidence of residual tumors except in one patient. Asymptomatic patients and patients with mixed-cellularity or lymphocytic-depleted Hodgkin's disease do significantly better than symptomatic patients and those with nodular sclerosing histologic type. Advanced Hodgkin's disease appears to be curable by chemotherapy.

Immunologic studies were done on 47 long-term survivors of Hodgkin's disease who had been treated with MOPP chemotherapy (mechlorethamine, vincristine, procarbazine, and prednisone). Percentages of E rosettes and mitogen-induced lymphocyte proliferation were significantly reduced compared to those in normal control subjects. There was no tendency for these abnormalities to return to the normal range with increasing disease-free intervals. No abnormalities of B-cell number or function were detected. Long-term survivors of advanced diffuse histiocytic lymphoma treated with comparable chemotherapy, who served as a control population, had significantly higher percentages of E rosettes and no reduction in mitogen-induced lymphocyte proliferation. Thus these persistent immunologic abnormalities cannot be attributed to chemotherapy alone. The presence of similar immunologic abnormalities in untreated patients with Hodgkin's disease of all stages and in patients cured by either MOPP or radiotherapy suggests that depressed cellular immunity may be an inherent characteristic of the person in whom Hodgkin's disease develops.

Twenty-seven patients with advanced diffuse histiocytic lymphoma (reticulum-cell sarcoma) were treated with combination chemotherapy utilising nitrogen mustard (or cyclophosphamide), procarbazine, vincristine, and prednisone. Elven (41%) achieved a complete remission and only one of these has had a recurrence of tumour. The remaining ten complete responders were free of all evidence of tumour when last seen 26-105 months from the end of treatment. In contrast, all non-responders or partial responders have died. An interpretation of published survival data suggests that this virulent disease evolves quickly and is usally rapidly fatal if treatment is unsuccessful. Survival free of disease beyond 2 years from the end of treatment may be considered tantamount to cure. This definition of cure, previously applied only to patients treated with radiotherapy, seems applicable to patients who acheive complete remissions with modern drug treatment.

Thirty-two patients with Hodgkin's disease who relapsed after a first complete remission induced by nitrogen mustard, vincristine, procarbazine, and prednisone (MOPP) were retreated with MOPP chemotherapy. Nineteen patients achieved a second complete remission. Median duration of the second complete remission was 21 months. The likelihood of achieving a second complete response could be predicted by the duration of the first response. Fourteen of 15 patients whose first complete remission was longer than 12 months achieved a second complete response in contrast to five of 17 patients whose initial complete remission lasted less than 12 months (P less than 0.001). Median survival of all patients in this study who were re-treated with MOPP was longer than 4 years after their first relapse. We conclude that patients with Hodgkin's disease who relapse after a first complete remission induced by MOPP are not necessarily resistant to further MOPP therapy and can achieve long-term survival with MOPP reinduction.

Eighty patients with advanced ovarian adenocarcinoma were treated in a prospective, randomized trial comparing a four-drug combination--hexamethylmelamine, cyclophosphamide, methotrexate and 5-fluorouracil--with the oral alkylating agent, melphalan. Treatment with the four-drug combination was associated with a significantly increased overall response rate (75 vs. 54 per cent) (P less than 0.05), more complete remissions (33 vs. 16 per cent) and longer median survival (29 vs. 17 months) (P less than 0.02) but more severe toxicity than occurred with melphalan. Patients with minimal residual disease had a significantly higher overall response rate than patients with extensive residual disease (84 vs. 53 per cent) (P less than 0.05). Patients with advanced disease who achieved a complete remission documented by peritoneoscopy or laparotomy (or both) have a median survival that will exceed three years. The four-drug regimen is more effective than melphalan in the management of advanced ovarian adenocarcinoma.

A significantly greater prevalence of interstitial pulmonary infiltrates and Pneumocystis carinii pneumonitis occurred on one arm of a randomized study comparing ProMACE-CytaBOM (prednisone, methotrexate with leucovorin, doxorubicin, cyclophosphamide, etoposide; cytarabine, bleomycin, vincristine, methotrexate with leucovorin) to ProMACE-MOPP (ProMACE, mechlorethamine, vincristine, prednisone, procarbazine) chemotherapy in patients with lymphoma. Of the 37 patients receiving ProMACE-CytaBOM, 13 (35.1%) developed an interstitial pulmonary infiltrate compared with 3 of 32 (9.4%) patients receiving ProMACE-MOPP (p2 = 0.02). Of the 13 patients receiving ProMACE-CytaBOM who had infiltrates, open lung biopsy in 7 showed P. carinii; 5 others had clinically suspected P. carinii pneumonia, and 1 had blastomycosis. No patient receiving ProMACE-MOPP had documented or suspected P. carinii pneumonia. Of patients with infiltrates, 3 of 13 on ProMACE-CytaBOM but 0 of 3 on ProMACE-MOPP died. Two other patients on ProMACE-CytaBOM who had P. carinii pneumonia died. Groups did not differ in predisposing risk factors or patient history. The exact cause for the increased prevalence of P. carinii infection in patients receiving ProMACE-CytaBOM was not ascertained. These data emphasize that new drug regimens may lead to unanticipated complications. [ABSTRACT FROM AUTHOR]

Seventy-nine patients with nodular mixed lymphoma were treated at the National Cancer Institute between 1966 and 1978. Fifteen patients had stage I or II disease, and 64, stage III or IV disease. The overall complete response rate for the patients that received various primary treatment regimens was 76%, with 52% of complete responders remaining in their first remission at a median follow-up of 7 years. Median survival of complete responders is projected to be more than 13 years. Median survival of patients who do not achieve complete remission is less than 2 years. Patients with B symptoms, bone marrow involvement, or a lactate dehydrogenase level greater than 250 U/mL had significantly shorter survivals than did patients without these features. Patients with advanced-stage (III and IV) nodular mixed lymphoma had a 72% complete response rate, with the average remission lasting more than 6 years. Although relapses have been seen up to 8 years after diagnosis in patients with nodular mixed lymphoma given C-MOPP chemotherapy (cyclophosphamide, vincristine, procarbazine, prednisone), prolonged initial remissions can be achieved with this therapy. [ABSTRACT FROM AUTHOR]