International Working Group consensus response evaluation criteria in lymphoma (RECIL 2017).

In recent years, the number of approved and investigational agents that can be safely administered for the treatment of lymphoma patients for a prolonged period of time has substantially increased. Many of these novel agents are evaluated in early-phase clinical trials in patients with a wide range of malignancies, including solid tumors and lymphoma. Furthermore, with the advances in genome sequencing, new "basket" clinical trial designs have emerged that select patients based on the presence of specific genetic alterations across different types of solid tumors and lymphoma. The standard response criteria currently in use for lymphoma are the Lugano Criteria which are based on [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography or bidimensional tumor measurements on computerized tomography scans. These differ from the RECIST criteria used in solid tumors, which use unidimensional measurements. The RECIL group hypothesized that single-dimension measurement could be used to assess response to therapy in lymphoma patients, producing results similar to the standard criteria. We tested this hypothesis by analyzing 47 828 imaging measurements from 2983 individual adult and pediatric lymphoma patients enrolled on 10 multicenter clinical trials and developed new lymphoma response criteria (RECIL 2017). We demonstrate that assessment of tumor burden in lymphoma clinical trials can use the sum of longest diameters of a maximum of three target lesions. Furthermore, we introduced a new provisional category of a minor response. We also clarified response assessment in patients receiving novel immune therapy and targeted agents that generate unique imaging situations.

The role of body mass index in survival outcome for lymphoma patients: US intergroup experience.

BACKGROUND: The role of body mass index (BMI) in survival outcomes is controversial among lymphoma patients. We evaluated the association between BMI at study entry and failure-free survival (FFS) and overall survival (OS) in three phase III clinical trials, among patients with diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and Hodgkin's lymphoma (HL). PATIENTS AND METHODS: A total of 537, 730 and 282 patients with DLBCL, HL and FL were included in the analysis. Baseline patient and clinical characteristics, treatment received and clinical outcomes were compared across BMI categories. RESULTS: Among patients with DLBCL, HL and FL, the median age was 70, 33 and 56; 29%, 29% and 37% were obese and 38%, 27% and 37% were overweight, respectively. Age was significantly different among BMI groups in all three studies. Higher BMI groups tended to have more favorable prognosis factors at study entry among DLBCL and HL patients. BMI was not associated with clinical outcome with P-values of 0.89, 0.30 and 0.40 for FFS, and 0.64, 0.67 and 0.09 for OS, for patients with DLBCL, HL and FL, respectively. The association remains non-significant after adjusting for other clinical factors in the Cox model. A subset analysis of males with DLBCL treated on R-CHOP revealed no differences in FFS (P = 0.48) or OS (P = 0.58). CONCLUSION: BMI was not significantly associated with clinical outcomes among patients with DLBCL, HD or FL, in three prospective phase III clinical trials. The findings contradict some previous reports of similar investigations. Further work is required to understand the observed discrepancies.

A phase II multicenter trial of hyperCVAD MTX/Ara-C and rituximab in patients with previously untreated mantle cell lymphoma; SWOG 0213.

BACKGROUND: Rituximab-hyper-CVAD alternating with rituximab-high-dose methotrexate and cytarabine is a commonly utilized regimen in the United States for mantle cell lymphoma (MCL) based on phase II single institutional data. To confirm the clinical efficacy of this regimen and determine its feasibility in a multicenter study that includes both academic and community-based practices, a phase II study of this regimen was conducted by SWOG. PATIENTS AND METHODS: Forty-nine patients with advanced stage, previously untreated MCL were eligible. The median age was 57.4 years (35-69.8 years). RESULTS: Nineteen patients (39%) did not complete the full scheduled course of treatment due to toxicity. There was one treatment-related death and two cases of secondary myelodysplastic syndrome (MDS). There were 10 episodes of grade 3 febrile neutropenia, 19 episodes of grade 3 and 1 episode of grade 4 infection. With a median follow-up of 4.8 years, the median progression-free survival was 4.8 years (5.5 years for those ≤ 65 years) and the median overall survival (OS) was 6.8 years. CONCLUSIONS: Although this regimen is toxic, it is active for patients ≤ 65 years of age and can be given both at academic centers and in experienced community centers.

Stromal gene signatures in large-B-cell lymphomas.

BACKGROUND: The addition of rituximab to combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), or R-CHOP, has significantly improved the survival of patients with diffuse large-B-cell lymphoma. Whether gene-expression signatures correlate with survival after treatment of diffuse large-B-cell lymphoma is unclear. METHODS: We profiled gene expression in pretreatment biopsy specimens from 181 patients with diffuse large-B-cell lymphoma who received CHOP and 233 patients with this disease who received R-CHOP. A multivariate gene-expression-based survival-predictor model derived from a training group was tested in a validation group. RESULTS: A multivariate model created from three gene-expression signatures--termed "germinal-center B-cell," "stromal-1," and "stromal-2"--predicted survival both in patients who received CHOP and patients who received R-CHOP. The prognostically favorable stromal-1 signature reflected extracellular-matrix deposition and histiocytic infiltration. By contrast, the prognostically unfavorable stromal-2 signature reflected tumor blood-vessel density. CONCLUSIONS: Survival after treatment of diffuse large-B-cell lymphoma is influenced by differences in immune cells, fibrosis, and angiogenesis in the tumor microenvironment.

Prognostic value of regulatory T cells, lymphoma-associated macrophages, and MUM-1 expression in follicular lymphoma treated before and after the introduction of monoclonal antibody therapy: a Southwest Oncology Group Study.

BACKGROUND: The purpose was to examine the prognostic impact of features of tumor cells and immune microenvironment in patients with follicular lymphoma treated with and without anti-CD20 monoclonal antibody therapy. PATIENTS AND METHODS: Tissue microarrays were constructed from archived tissue obtained from patients on three sequential Southwest Oncology Group (SWOG) trials for FL. All three trials included anthracycline-based chemotherapy. Anti-CD20 monoclonal antibodies were included for patients in the latter two trials. Immunohistochemistry was used to study the number and distribution of cells staining for forkhead box protein P3 (FOXP3) and lymphoma-associated macrophages (LAMs) and the number of lymphoma cells staining for myeloma-associated antigen-1 (MUM-1). Cox proportional hazards regression was used to evaluate the association between marker expression and overall survival (OS). RESULTS: The number or pattern of infiltrating FOXP3 cells and LAMs did not correlate with OS in sequential SWOG studies for FL. The presence of MUM-1 correlated with lower OS for patients who received monoclonal antibody but not for those treated with chemotherapy alone. CONCLUSIONS: Immune cell composition of lymph nodes did not correlate with OS in this analysis of trials in FL. The mechanism of the observed correlation between MUM-1 expression and adverse prognosis in patients receiving monoclonal antibody therapy requires confirmation.

Bortezomib in patients with relapsed or refractory mantle cell lymphoma: updated time-to-event analyses of the multicenter phase 2 PINNACLE study.

BACKGROUND: We previously reported results of the phase 2, multicenter PINNACLE study, which confirmed the substantial single-agent activity of bortezomib in patients with relapsed or refractory mantle cell lymphoma (MCL). MATERIALS AND METHODS: We report updated time-to-event data, in all patients and by response to treatment, after extended follow-up (median 26.4 months). RESULTS: Median time to progression (TTP) was 6.7 months. Median time to next therapy (TTNT) was 7.4 months. Median overall survival (OS) was 23.5 months. In responding patients, median TTP was 12.4 months, median duration of response (DOR) was 9.2 months, median TTNT was 14.3 months, and median OS was 35.4 months. Patients achieving complete response had heterogeneous disease characteristics; among these patients, median TTP and DOR were not reached, and median OS was 36.0 months. One-year survival rate was 69% overall and 91% in responding patients. Median OS from diagnosis was 61.1 months, after median follow-up of 63.7 months. Activity was seen in patients with refractory disease and patients relapsing following high-intensity treatment. Toxicity was generally manageable. CONCLUSIONS: Single-agent bortezomib is associated with lengthy responses and notable survival in patients with relapsed or refractory MCL, with considerable TTP and TTNT in responding patients, suggesting substantial clinical benefit.

Bortezomib and gemcitabine in relapsed or refractory Hodgkin's lymphoma.

BACKGROUND: Given the significant activity and tolerability of gemcitabine in patients with relapsed Hodgkin's lymphoma (HL), the critical role that nuclear factor kappa B (NF-kappaB) appears to play in the pathogenesis of this tumor, the ability of bortezomib to inhibit NF-kappaB activity, and laboratory studies suggesting synergistic antitumor effects of gemcitabine and bortezomib, we hypothesized that this combination would be efficacious in patients with relapsed or refractory HL. PATIENTS AND METHODS: A total of 18 patients participated. Patients received 3-week cycles of bortezomib 1 mg/m(2) on days 1, 4, 8, and 11 plus gemcitabine 800 mg/m(2) on days 1 and 8. RESULTS: The overall response rate for all patients was 22% (95% confidence interval 3% to 42%). Three patients developed grade III transaminase elevation: one was removed from the study and two had doses of gemcitabine held. Almost all patients exhibited inhibition of proteasome activity with treatment. CONCLUSIONS: The combination of gemcitabine and bortezomib is a less active and more toxic regimen in relapsed HL than other currently available treatments. It poses a risk of severe liver toxicity and should be pursued with caution in other types of cancer.

Lymphocytes in patients with variable immunodeficiency and panhypogammaglobulinemia. Evaluation of B and T cell surface markers and a proposed classification.

Peripheral blood lymphocytes from 15 patients with variable immunodeficiency and severe panhypogammaglobulinemia were evaluated for B and T cell surface markers. B cells were enumerated by immunofluorescent detection of both surface immunoglobulin (Ig) and the ability to bind aggregated Ig complexes. T cells were identified by their ability to form nonimmune rosettes with sheep red blood cells. Four distinct patterns were observed which were designated types I-IV. Type I: six patients had normal percentages (8.5-19.0%) of Ig-bearing B lymphocytes. Type II: four patients were observed to have B lymphocytes (4.5-15.0%) which lacked fluorescence-detectable surface Ig. Type III: the peripheral blood of these four patients contained a subpopulation (11.3-20.0%) of lymphocytes which apparently lacked both B and T cell markers ("null" cells). Type IV: one patient's blood was characterized by a subpopulation (18.0-22.0%) of lymphocytes which bore both B and T cell markers. Patients of each type had some clinical features in common. It is concluded that evaluation of lymphocyte surface markers provides a means of separating patients with variable immunodeficiency and panhypogammaglobulinemia into distinct groups which appear to differ in the nature of their fundamental defect.

Effects of interleukin 2 on cardiac function in the isolated rat heart.

Adoptive immunotherapy with IL 2 is associated with severe cardiovascular toxicities including peripheral and pulmonary edema, hypotension decreased systemic vascular resistance, increased heart rate, and an increased cardiac index. The purpose of this investigation was to determine whether IL 2 alone or in combination with lymphokine-activated killer cells (LAK) cells depress cardiac function using the isolated, perfused, working rat heart preparation. Male Sprague-Dawley rats (250-350 g) were anesthetized and the hearts were removed and placed on the perfusion apparatus. Hearts were perfused with oxygenated Krebs-Henseleit buffer (KHB), or oxygenated KHB containing IL 2 alone, IL 2-Media (cell culture media supplemented with 1,500 U IL 2/ml), LYMPH (cell culture media from cultured mononuclear cells from healthy volunteers), or LAK (cell culture media from cultured lymphocytes harvested from patients receiving IL 2/LAK in the presence of 1,500 U/ml IL 2). The cells were removed before perfusion (n = 9). Cardiac output and coronary flow were measured at 20-min intervals with preload constant (afterload varied or afterload constant (preload varied). The results indicate a significant depression in cardiac function in hearts treated with LAK. This depression was evident at 20 min and was more pronounced at 60 min. Washout of the KHB plus LAK reversed this depression. Thus, IL 2-stimulated/cultured human mononuclear cells produce a soluble factor that produces a reversible severe depression of cardiac function.

The biology of tumor growth in the non-Hodgkin's lymphomas. A dual parameter flow cytometry study of 220 cases.

Dual parameter flow cytometry studies (cell DNA content and electronic cell volume) were performed in 220 cases of non-Hodgkin's lymphoma. All cases were characterized as B or T cell malignancies, based on immunologic surface marker characteristics. Aneuploidy by flow cytometry was more common among the B cell lymphomas than among the T cell lymphomas, and was most common among the large B cell lymphomas and B cell lymphomas of intermediate size. Ploidy index distributions showed a prominent hyperdiploid peak, as well as tumor cell populations with near-tetraploid DNA contents. In serial studies, a decrease in ploidy index was observed in association with clinical and histologic transformation in one case. The highest S fractions were observed among the large and intermediate B cell lymphomas and among the aggressive T cell lymphomas. In clinical samples consisting of mixtures of diploid and aneuploid populations, the data on the aneuploid components could often be separated from other components of the mixture in multiparameter studies on the basis of the larger electronic cell volumes of the aneuploid cells. In each case, the aneuploid large cell component almost invariably had a higher S fraction than the residual component(s) of the mixture. Overall, the data are consistent with a model of clonal selection and clonal evolution in the lymphomas in which early cytogenetic abnormalities that involve little or no change in total cell DNA content are followed by cell tetraploidization that is associated with cytogenetic instability and chromosome loss over the course of time.

Meta-analysis to evaluate the role of interferon in follicular lymphoma.

PURPOSE: To determine whether interferon (IFN) -alpha2, when given with or following chemotherapy, influences response rate, remission duration, and survival in newly diagnosed patients with follicular lymphoma. PATIENTS AND METHODS: Ten phase III studies evaluating the role of IFN-alpha2 in 1,922 newly diagnosed patients with follicular lymphoma were analyzed. Updated individual patient data were used to perform meta-analyses for response, survival, and remission duration. RESULTS: The addition of IFN-alpha2 to initial chemotherapy did not significantly influence response rate. An overall meta-analysis for survival showed a significant difference in favor of IFN-alpha2, but also showed significant heterogeneity between studies. Further analyses were carried out in order to explain this heterogeneity, and to define the circumstances in which IFN-alpha2 prolonged survival. The survival advantage was seen when IFN-alpha2 was given: (1) in conjunction with relatively intensive initial chemotherapy (2P = .00005), (2) at a dose >/= 5 million units (2P = .000002), (3) at a cumulative dose >/= 36 million units per month (2P = .000008), and (4) with chemotherapy rather than as maintenance therapy (P = .004). With regard to remission duration, there was also a significant difference in favor of IFN-alpha2, irrespective of the intensity of chemotherapy used, IFN dose, or whether IFN was given as a maintenance strategy or with chemotherapy. CONCLUSION: When given in the context of relatively intensive initial chemotherapy, and at a dose >/= 5 million units (>/= 36 x 10(6) units per month), IFN-alpha2 prolongs survival and remission duration in patients with follicular lymphoma.

Phase I study of streptozocin- and carmustine-sequenced administration in patients with advanced cancer.

BACKGROUND: Fewer than 20% of patients with nonhematologic malignancies treated with chloroethylnitrosoureas (CENUs) respond, but streptozocin (STZ), which depletes O6-methylguanine-DNA-methyltransferase (MGMT), has been shown to reverse resistance to CENUs in vitro. PURPOSE: The purpose of this phase I study was to determine (a) the maximum tolerated dose (MTD) of carmustine (BCNU), a CENU, plus a fixed dose of STZ; (b) the toxic effects of the drugs; and (c) the effects on peripheral blood mononuclear cells (PBMC). METHODS: A clinical phase I study of STZ followed by BCNU was designed to simulate conditions that produce maximal sensitization of CENU-resistant HT-29 cells in vitro. Patients received a 20-minute infusion of the MTD of STZ (2 g/m2) followed 1 hour later with a 60-minute infusion of BCNU (100, 125, 137.5, or 150 mg/m2). Treatment was repeated after 6 weeks. Twenty-four patients with advanced malignancies received 32 courses of therapy (range, 1-2 courses). RESULTS: The MTD of BCNU was 125 mg/m2. The dose-limiting toxic effect was thrombocytopenia occurring about 22 days after treatment, with recovery between days 28 and 35. Transient hypophosphatemia and proteinuria were common, and serum creatinine was elevated in 9% of the courses. Two patients who received therapy died--one due to pulmonary toxic effects and one due to hepatic toxic effects. Two patients with previously untreated carcinoid achieved partial response. In three patients, MGMT levels in PBMC were more than 85% depleted after STZ administration and more than 90% depleted after BCNU infusion. CONCLUSIONS: These results show that the magnitude of MGMT depletion by STZ in PBMC is in the range necessary to produce sensitivity to CENUs in resistant cell lines but also that, when BCNU is combined with STZ, the MTD of BCNU is about 50% that of BCNU as a single agent and that platelet count suppression occurs earlier. IMPLICATIONS: We plan to conduct phase II studies of STZ plus BCNU in tumor types with low response to CENUs. One of the major goals will be to demonstrate that depletion of MGMT is greater in tumor cells than in normal cells.

Phase I study of high-dose continuous-infusion recombinant interleukin-2 and autologous lymphokine-activated killer cells in patients with metastatic or unresectable malignant melanoma and renal cell carcinoma.

The current study was undertaken to determine the maximum tolerated dose of recombinant interleukin-2 (rIL-2) that could be administered as a continuous infusion in conjunction with autologous lymphokine-activated killer (LAK) cells. All 55 patients in this study received a priming dose of rIL-2 of 1.0 mg/m2 per day given as a continuous infusion over 4.5 days. Patients later received (days 11-16) one of three doses of rIL-2 per day (1.0, 1.25, or 1.50 mg/m2) in conjunction with LAK cells given on days 11, 12, and 14. Because of unacceptable toxicity occurring early in the LAK cell phase of therapy at the rIL-2 dose level of 1.50 mg/m2, we concluded that the maximum tolerated dose of rIL-2 given as a continuous infusion with LAK cells is 1.25 mg/m2 per day.

Requirements for successful immunotherapy and chemoimmunotherapy of a murine model of ovarian cancer.

A comprehensive study of nonspecific immunotherapy has been conducted in an established murine model of ovarian cancer in order to determine the relative effectiveness of commonly used bacterial immunostimulants, the importance of the route and schedule of administration of these agents, and their effects in combination with chemotherapy. Implants of 10(5) or 10(6) ovarian tumor cells i.p. kill all syngeneic C3HeB/FeJ mice within 25 days. Corynebacterium parvum (700 microgram/mouse i.p. 24 hr after a 10(5) tumor cell inoculum) cures 75% of the mice; in contrast, neither i.v. nor s.c. administration improves survival rates. After the same tumor challenge, Bacillus Calmette-Guérin was minimally effective at extremely high doses only, while the methanol extraction residue of B. Calmette-Guérin was ineffective. Two days after an implant of 10(6) tumor cells, neither cyclophosphamide, nor cis-diamminedichloroplastinum(II) (cisplatin), nor C. parvum increased survival. Combination of C. parvum with cyclophosphamide or cisplatin resulted in a synergism shown by the 40 and 60% cure rates, respectively. However, combination of C. parvum with an active agent, doxorubicin, resulted in toxicity even in untumored animals. This study demonstrates that therapeutic efficacy of immunotherapy depends critically on the choice of an appropriate agent and route of administration and, to a lesser extent, on the dose and schedule used. The observation provides a rationale for carefully conducted Phase I and Phase II studies of treatment with bacterial immunostimulants, alone or in combination with chemotherapy, in human ovarian cancer.

Lack of histocompatibility antigens on a murine ovarian teratocarcinoma.

We have attempted to generate in vitro lymphocytes cytotoxic to a widely studied model of ovarian cancer in C3HeB/FeJ mice. These attempts were unsuccessful with either syngeneic or allogeneic spleen cells. The following experimental results demonstrated that this murine ovarian tumor lacks histocompatibility antigens. (a) Tumor cells were not lysed by allogeneic lymphocytes presensitized to H-2k spleen cells. (b) Tumor cells did not specifically inhibit the cell-mediated lysis of H-2k spleen cells by presensitized allogeneic lymphocytes. (c) Histoincompatible (H-2b or H-2d) and syngeneic (H-2k) mice all died with identical tumor growth patterns within 25, 30, or 35 days following the i.p. inoculation of 10(6), 10(5), or 10(4) tumor cells, respectively. (d) Tumor cells were not lysed by an anti-H-2k antiserum and complement. (e) Absorption of the anti-H-2k antiserum with tumor cells did not decrease the cytotoxicity of the antiserum. (f) Competitive inhibition of a radioimmunoassay and polyacrylamide gel electrophoresis of immunoprecipitate of radiolabeled tumor extracts failed to demonstrate an H-2 heavy chain, although a normal amount of beta-microglobulin was present. This lack of histocompatibility antigens may explain the failure to generate lymphocytes cytotoxic to this tumor. Thus, this murine ovarian tumor, which has a serologically detectable tumor-associated antigen and can be cured by nonspecific immunotherapy, may provide an excellent model for the study of successful immunotherapy in the absence of histocompatibility antigens and associated cell-mediated reactions.

Identification of a novel CD56- lymphokine-activated killer cell precursor in cancer patients receiving recombinant interleukin 2.

Circulating lymphokine-activated killer (LAK) cell activity in cancer patients receiving recombinant interleukin 2 (rIL-2) therapy is confined to cells expressing the CD56- surface marker. However, CD56- cells from these patients but not normal individuals have been reported to exhibit LAK cytotoxicity only following in vitro activation with rIL-2. Studies were performed to document the existence of CD56- LAK precursor cells and to phenotypically characterize this population in patients receiving rIL-2 therapy using fluorescence-activated cell sorter-purified CD56- cell subsets. Initial studies confirmed that CD56- cells exhibit NK activity [20 +/- 7 (SE) LU/10(6) cells] but not LAK activity (0 +/- 0 LU/10(6) cells) when evaluated directly from peripheral blood of patients receiving rIL-2. CD56- cells from patients but not normal individuals developed significant LAK cytolytic activity against NK-resistant COLO 205 targets (16 +/- 3 LU/10(6) cells) when cultured for 3 days with 1500 units/ml rIL-2. The CD56- LAK precursor activity was confined to cells expressing a CD56-CD16+ phenotype and a large granular lymphocyte morphology; little or no NK or LAK precursor activity was detectable in CD56-CD5+ T-cells from patients. Phenotypic characterization of CD16+CD56- cells revealed that this population is uniformly CD11a+,CD18+, and CD38+ and is heterogeneous in its expression of CD11b, CD11c, and CD16/Leu 11c. These results indicate that rIL-2 administration induces enhanced LAK precursor activity in a novel population of CD5-CD16+CD56- cells.

Controlled clinical trials of nutritional intervention as an adjunct to chemotherapy, with a comment on nutrition and drug resistance.

Nutritional intervention in the cancer patient [e.g., total parenteral nutrition (TPN)] might improve durable survival because of increased tolerance to aggressive tumor therapy. To determine whether this assumption is correct, 42 patients with diffuse histiocytic lymphoma were induced with prednisone, high-dose methotrexate, Adriamycin, cyclophosphamide, and VP-16 (ProMACE). Nitrogen mustard-vincristine-procarbazine-prednisone (MOPP) consolidation was then used, followed by late intensification with ProMACE. Patients were selected randomly to receive adjuvant TPN or a standard diet during ProMACE-MOPP treatment. While TPN patients had a greater median weight gain than did control patients, lean body mass and degree of myelosuppression did not improved as a consequence of TPN. There was no significant difference in tumor response or survival between TPN and control patients, whether or not the patients were initially malnourished. In a second trial, 32 young patients with metastatic or other poor-prognosis sarcomas were randomly allocated to receive TP or a standard diet as an adjunct to one very intensive course of combination chemotherapy or chemotherapy plus total body irradiation; autologous marrow transplantation was used with gain than did controls but remained in a negative nitrogen balance. Response rates and median durable survival did not differ between the two groups. In both trials, the maximum nutritional support permitted by currently available technology was offered. Thus, the limiting factor may not be nutritional status but rather the intrinsic biology of the tumors and the limitations of their response to current therapy. In in vitro studies of the possible influence of nutrition on cancer treatment, we have compared sublines of P388 murine leukemia cells which are sensitive or resistant to Adriamycin. The difference in drug sensitivity correlated with differences in lipid composition, with more intracellular lipid, and with greater membrane rigidity in the resistant cells. Resistant cells have a relatively poor transport of drug into the cell; moreover, intracellular Adriamycin is sequestered in lipid depots away from DNA. These results suggest one possible relationship between nutritional phenomena and drug sensitivity.

Objective regressions of T- and B-cell lymphomas in patients following treatment with anti-thymocyte globulin.

We have conducted a clinical trial utilizing anti-thymocyte globulin (ATG) for the treatment of patients with non-Hodgkin's lymphomas. Six patients were treated; 50% reductions in tumor mass of short duration were observed in one patient with a T-cell lymphoma and two patients with B-cell lymphomas. In vitro assays have been performed in an attempt to study the reactivity and potential mechanism of antitumor action of the ATG. The ATG bound to essentially all normal blood mononuclear leukocytes as well as tumor cells from patients with T-, B-, or null cell lymphomas demonstrating its lack of specificity. Furthermore, complement-mediated lysis of normal mononuclear leukocytes, normal T- or B-cells, and tumor cells from two unresponsive patients were all comparable; moreover, since this lysis occurred only at concentrations of ATG that are not attainable in vivo, it is unlikely that complement-mediated cytotoxicity accounts for the responses observed. Peripheral blood lymphocyte counts and total erythrocyte rosettes did decrease during ATG treatment. Thus, objective tumor responses in both B- and T-cell non-Hodgkin's lymphomas can be achieved with a very nonspecific antiserum although significant toxicity resulted. Whether the magnitude or duration of response can be increased with monoclonal antibodies remains to be determined. Future success with serotherapy might require use of either a battery of different monoclonal antibodies or a single monoclonal antibody that can deliver radioisotopes, chemotherapy, or toxins to the tumor cells.

Diversity of immunological phenotypes of lymphoblastic lymphoma.

Eleven cases of lymphoblastic malignancy, presenting as lymphoma, were investigated for immunological and differentiation markers prior to the onset of therapy. Biopsy specimens exhibited the typical morphological features of lymphoblastic lymphoma (convoluted T-cell lymphoma). Intranuclear terminal deoxynucleotidyl transferase was detected in the neoplastic cells from each case by indirect antibody staining of cytocentrifuge preparations. Eight cases were T-cell type as evidenced by unsensitized sheep erythrocyte rosette formation and staining with the monoclonal antibody OKT11. Three T-cell cases were OKT4 positive, two were OKT8 positive, and none were positive with both OKT4 and OKT8. Three cases failed to react with any monoclonal antibodies specific for T-cells and did not form unsensitized sheep erythrocyte rosettes or stain for surface immunoglobulin. However, these three cases were Ia positive and J5 (common acute lymphoblastic leukemia antigen) positive. Cells from two of these erythrocyte rosette-negative, Ia-positive, common acute lymphoblastic leukemia-positive cases contained intracytoplasmic mu heavy chains and were therefore of pre-B-cell phenotype. These cases were histologically indistinguishable from the T-cell cases. However, clinically, they were distinguished by the absence of mediastinal masses and by a clinical presentation as isolated lytic lesions of bone in two of the three. OKT9 and OKT10 stained neoplastic cells from T-cell, as well as pre-B-lymphoblastic, lymphoma. Although morphologically homogeneous, lymphoblastic lymphomas are comprised of an immunologically diverse group of neoplasms which include cells of "common" and "mature" thymocyte, non-T, non-B, and pre-B phenotypes and are closely related to the cells of acute lymphoblastic leukemia. In addition, intratumor heterogeneity was observed in most instances and may reflect growth or differentiation differences between subpopulations of individual neoplastic clones.

1-beta-D-arabinofuranosylcytosine and hydroxyurea production of cytotoxic synergy with cis-diamminedichloroplatinum(II) and modification of platinum-induced DNA interstrand cross-linking.

1-beta-D-Arabinofuranosylcytosine (ara-C) and hydroxyurea (HU) were investigated as possible inhibitors for the repair of cis-diamminedichloroplatinum(II) (DDP)-induced DNA damage. HU and ara-C were chosen for their known ability to inhibit DNA excision repair following UV irradiation. Work by several groups has suggested that the repair of DDP-induced DNA damage may involve an excision-repair mechanism. The cytotoxic effects of dose, exposure duration, and sequence for the three drugs was studied in a human colon cancer cell line (HT-29) by colony formation assays. Significant synergistic cytotoxicity was seen whether HU + ara-C were given prior to, or following DDP exposure. Cytotoxic synergy was also seen between HU + ara-C themselves. The effect of the combined antimetabolites on the level and persistence of DDP-induced DNA interstrand cross-links was assessed by DNA alkaline elution. These were measured as an indicator of DDP-DNA adduct formation and removal. When HU + ara-C exposure preceded or followed DDP treatment, higher levels of interstrand cross-linking were found at late time points than were seen with DDP alone, suggesting repair inhibition. We conclude that the combination of HU, ara-C, and DDP shows synergistic cytotoxicity, and that this effect may be due in part to inhibition of DDP-induced DNA adduct repair. The concentrations of drugs used in vitro are achievable in humans. On the basis of these results, a Phase I/II clinical trial of the three agents in combination has been initiated.