Thomas E. Witzig

Effective Surgical Adjuvant Therapy for High-Risk Rectal Carcinoma

BACKGROUND Radiation therapy as an adjunct to surgery for rectal cancer has been shown to reduce local recurrence but has not improved survival. In a previous study, combined radiation and chemotherapy improved survival significantly as compared with surgery alone, but not as compared with adjuvant radiation, which many regard as standard therapy. We designed a combination regimen to optimize the contribution of chemotherapy, decrease recurrence, and improve survival as compared with adjuvant radiation alone. METHODS Two hundred four patients with rectal carcinoma that was either deeply invasive or metastatic to regional lymph nodes were randomly assigned to postoperative radiation alone (4500 to 5040 cGy) or to radiation plus fluorouracil, which was both preceded and followed by a cycle of systemic therapy with fluorouracil plus semustine (methyl-CCNU). RESULTS After a median follow-up of more than seven years, the combined therapy had reduced the recurrence of rectal cancer by 34 percent (P = 0.0016; 95 percent confidence interval, 12 to 50 percent). Initial local recurrence was reduced by 46 percent (P = 0.036; 95 percent confidence interval, 2 to 70 percent), and distant metastasis by 37 percent (P = 0.011; 95 percent confidence interval, 9 to 57 percent). In addition, combined therapy reduced the rate of cancer-related deaths by 36 percent (P = 0.0071; 95 percent confidence interval, 14 to 53 percent) and the overall death rate by 29 percent (P = 0.025; 95 percent confidence interval, 7 to 45 percent). Its acute toxic effects included nausea, vomiting, diarrhea, leukopenia, and thrombocytopenia. These effects were seldom severe. Severe, delayed treatment-related reactions, usually small-bowel obstruction requiring surgery, occurred in 6.7 percent of all patients receiving radiation, and the frequencies of these complications were comparable in both treatment groups. CONCLUSIONS The combination of postoperative local therapy with radiation plus fluorouracil and systemic therapy with a fluorouracil-based regimen significantly and substantively improves the results of therapy for rectal carcinoma with a poor prognosis, as compared with postoperative radiation alone.

Review of 1027 Patients With Newly Diagnosed Multiple Myeloma

OBJECTIVE To determine the clinical and laboratory features of newly diagnosed multiple myeloma. PATIENTS AND METHODS Records of all patients in whom multiple myeloma was initially diagnosed at the Mayo Clinic in Rochester, Minn, from January 1, 1985, to December 31, 1998, were reviewed. RESULTS Of the 1027 study patients, 2% were younger than 40 years, and 38% were 70 years or older. The median age was 66 years. Anemia was present initially in 73% of patients, hypercalcemia (calcium level > or = 11 mg/dL) in 13%, and a serum creatinine level of 2 mg/dL or more in 19%. The beta2-microglobulin level was increased in 75%. Serum protein electrophoresis revealed a localized band in 82% of patients, and immunoelectrophoresis or immunofixation showed a monoclonal protein in 93%. A monoclonal light chain was found in the urine in 78%. Nonsecretory myeloma was recognized in 3% of patients, whereas light-chain myeloma was present in 20%. Conventional radiographs showed an abnormality in 79%. The plasma cell labeling index was 1% or more in 34% of patients. Multivariate analysis revealed that age, plasma cell labeling index, low platelet count, serum albumin value, and the log of the creatinine value were the most important prognostic factors. CONCLUSION The median duration of survival was 33 months and did not improve from 1985 through 1998.

Randomized Controlled Trial of Yttrium-90–Labeled Ibritumomab Tiuxetan Radioimmunotherapy Versus Rituximab Immunotherapy for Patients With Relapsed or Refractory Low-Grade, Follicular, or Transformed B-Cell Non-Hodgkin’s Lymphoma

PURPOSE Radioimmunotherapy combines biologic and radiolytic mechanisms to target and destroy tumor cells, thus offering a needed therapeutic alternative for refractory non-Hodgkins lymphoma (NHL) patients. This phase III randomized study compares the novel radioimmunotherapy yttrium-90 ((90)Y) ibritumomab tiuxetan with a control immunotherapy, rituximab, in 143 patients with relapsed or refractory low-grade, follicular, or transformed CD20(+) transformed NHL. PATIENTS AND METHODS Patients received either a single intravenous (IV) dose of (90)Y ibritumomab tiuxetan 0.4 mCi/kg (n = 73) or rituximab 375 mg/m(2) IV weekly for four doses (n = 70). The radioimmunotherapy group was pretreated with two rituximab doses (250 mg/m(2)) to improve biodistribution and one dose of indium-111 ibritumomab tiuxetan for imaging and dosimetry. The primary end point, overall response rate (ORR), was assessed by an independent, blinded, lymphoma expert panel. RESULTS ORR was 80% for the (90)Y ibritumomab tiuxetan group versus 56% for the rituximab group (P =.002). Complete response (CR) rates were 30% and 16% in the (90)Y ibritumomab tiuxetan and rituximab groups, respectively (P =.04). An additional 4% achieved an unconfirmed CR in each group. Kaplan-Meier estimated median duration of response was 14.2 months in the (90)Y ibritumomab tiuxetan group versus 12.1 months in the control group (P =.6), and time to progression was 11.2 versus 10.1 months (P =.173) in all patients. Durable responses of > or = 6 months were 64% versus 47% (P =.030). Reversible myelosuppression was the primary toxicity noted with (90)Y ibritumomab tiuxetan. CONCLUSION Radioimmunotherapy with (90)Y ibritumomab tiuxetan is well tolerated and produces statistically and clinically significant higher ORR and CR compared with rituximab alone.

Targeting Apoptosis Pathways in Cancer Therapy

Apoptosis, or programmed cell death, is a mechanism by which cells undergo death to control cell proliferation or in response to DNA damage. The understanding of apoptosis has provided the basis for novel targeted therapies that can induce death in cancer cells or sensitize them to established cytotoxic agents and radiation therapy. These novel agents include those targeting the extrinsic pathway such as tumor necrosis factor‐related apoptosis‐inducing ligand receptor 1, and those targeting the intrinsic Bcl‐2 family pathway such as antisense bcl‐2 oligonucleotides. Many pathways and proteins control the apoptosis machinery. Examples include p53, the nuclear factor kappa B, the phosphatidylinositol 3 kinase pathway, and the ubiquitin/proteosome pathway. These can be targeted by specific modulators such as bortezomib, and mammalian target of rapamycin inhibitors such as CCI‐779 and RAD 001. Because these pathways may be preferentially altered in tumor cells, there is potential for a selective effect in tumors sparing normal tissue. This article reviews the current understanding of the apoptotic pathways, including the extrinsic (cytoplasmic) and intrinsic (mitochondrial) pathways, and the agents being developed to target these pathways.

Treatment With Ibritumomab Tiuxetan Radioimmunotherapy in Patients With Rituximab-Refractory Follicular Non-Hodgkin’s Lymphoma

PURPOSE Rituximab is commonly used as a single agent or in combination therapy for non-Hodgkins lymphoma (NHL). Ibritumomab tiuxetan radioimmunotherapy targets the same antigen as rituximab and has demonstrated efficacy in rituximab-naïve NHL. This study evaluated ibritumomab tiuxetan in the treatment of rituximab-refractory follicular NHL. PATIENTS AND METHODS Eligible patients were refractory to rituximab; this was defined as no objective response to rituximab (375 mg/m(2) weekly for 4 weeks) or time to progression (TTP) of < or = 6 months. The ibritumomab tiuxetan treatment regimen consisted of pretreatment with rituximab (250 mg/m(2) intravenously on days 1 and 8) to deplete peripheral blood B cells, then yttrium-90 ibritumomab tiuxetan (0.4 mCi/kg; maximum, 32 mCi) intravenously on day 8, administered on an outpatient basis. An imaging/dosimetry dose of indium-111 ibritumomab tiuxetan (5 mCi) was injected after rituximab (day 1) in 28 patients. RESULTS Fifty-seven patients were treated. The median age was 54 years, 74% had tumors > or = 5 cm, and all were extensively pretreated (median, four prior therapies; range, one to nine). The estimated radiation-absorbed doses to healthy organs were below the study-defined limit in all patients studied with dosimetry. The overall response rate for the 54 patients with follicular NHL was 74% (15% complete responses and 59% partial responses). The Kaplan-Meier-estimated TTP was 6.8 months (range, 1.1 to > or = 25.9 months) for all patients and 8.7 months for responders. Adverse events were primarily hematologic; the incidence of grade 4 neutropenia, thrombocytopenia, and anemia was 35%, 9%, and 4%, respectively. CONCLUSION Ibritumomab tiuxetan radioimmunotherapy is effective in rituximab-refractory patients. The only significant toxicity is hematologic.

A Trial of Three Regimens for Primary Amyloidosis: Colchicine Alone, Melphalan and Prednisone, and Melphalan, Prednisone, and Colchicine

BACKGROUND Primary systemic amyloidosis is an uncommon disease characterized by the accumulation in vital organs of a fibrillar protein consisting of monoclonal light chains. METHODS We treated 220 patients with biopsy-proved amyloidosis. The patients were randomly assigned to receive colchicine (72 patients), melphalan and prednisone (77), or melphalan, prednisone, and colchicine (71). They were stratified according to their chief clinical manifestations: renal disease (105 patients), cardiac involvement (46), peripheral neuropathy (19), or other (50). RESULTS The median duration of survival after randomization was 8.5 months in the colchicine group, 18 months in the group assigned to melphalan and prednisone, and 17 months in the group assigned to melphalan, prednisone, and colchicine (P<0.001). Among patients who had a reduction in serum or urine monoclonal protein at 12 months, the overall length of survival was 50 months, whereas among those without a reduction at 12 months, the overall length of survival was 36 months (P=0.03). Thirty-four patients (15 percent) survived for five years or longer. CONCLUSIONS Therapy with melphalan and prednisone results in objective responses and prolonged survival as compared with colchicine in patients with primary amyloidosis.

Combination Therapy With Thalidomide Plus Dexamethasone for Newly Diagnosed Myeloma

PURPOSE Multiple myeloma is a malignancy of plasma cells and is characterized by increased marrow angiogenesis. Thalidomide, an agent with antiangiogenic properties, is effective in relapsed myeloma. We report the results of a study combining thalidomide and dexamethasone as initial therapy for myeloma. PATIENTS AND METHODS Fifty patients with newly diagnosed myeloma were studied. Thalidomide was given at a dose of 200 mg/d orally. Dexamethasone was given at a dose of 40 mg/d orally on days 1 to 4, 9 to 12, and 17 to 20 (odd cycles) and 40 mg/d on days 1 to 4 (even cycles), repeated monthly. RESULTS Of all 50 patients, a confirmed response was seen in 32 patients yielding a response rate of 64% (95% confidence interval, 49% to 77%). Thirty-one patients (62%) proceeded to stem-cell collection after four cycles of therapy including 26 who underwent stem-cell transplantation and five who chose stem-cell cryopreservation. Major grade 3 or 4 toxicities were observed in 16 patients (32%), and the most frequent were deep vein thrombosis (six patients), constipation (four patients), rash (three patients), and dyspnea (two patients). Three deaths occurred during active therapy because of a pancreatitis, pulmonary embolism, and infection. CONCLUSION We conclude that the combination of thalidomide plus dexamethasone is a feasible and active regimen in the treatment of multiple myeloma. It merits further study as an oral alternative to infusional chemotherapy with vincristine, doxorubicin, and dexamethasone and other intravenous regimens currently used as pretransplantation induction therapy for myeloma.

Phase I/II Trial of IDEC-Y2B8 Radioimmunotherapy for Treatment of Relapsed or Refractory CD20+ B-Cell Non-Hodgkin's Lymphoma

PURPOSE Yttrium-90 ibritumomab tiuxetan (IDEC-Y2B8) is a murine immunoglobulin G1 kappa monoclonal antibody that covalently binds MX-DTPA (tiuxetan), which chelates the radioisotope yttrium-90. The antibody targets CD20, a B-lymphocyte antigen. A multicenter phase I/II trial was conducted to compare two doses of unlabeled rituximab given before radiolabeled antibody, to determine the maximum-tolerated single dose of IDEC-Y2B8 that could be administered without stem-cell support, and to evaluate safety and efficacy. PATIENTS AND METHODS Eligible patients had relapsed or refractory (two prior regimens or anthracycline if low-grade disease) CD20(+) B-cell low-grade, intermediate-grade, or mantle-cell non-Hodgkins lymphoma (NHL). There was no limit on bulky disease, and 59% had at least one mass > or = 5 cm. RESULTS The maximum-tolerated dose was 0.4 mCi/kg IDEC-Y2B8 (0.3 mCi/kg for patients with baseline platelet counts 100 to 149,000/microL). The overall response rate for the intent-to-treat population (n = 51) was 67% (26% complete response [CR]; 41% partial response [PR]); for low-grade disease (n = 34), 82% (26% CR; 56% PR); for intermediate-grade disease (n = 14), 43%; and for mantle-cell disease (n = 3), 0%. Responses occurred in patients with bulky disease (> or = 7 cm; 41%) and splenomegaly (50%). Kaplan-Meier estimate of time to disease progression in responders and duration of response is 12.9+ months and 11.7+ months, respectively. Adverse events were primarily hematologic and correlated with baseline extent of marrow involvement with NHL and baseline platelet count. One patient (2%) developed an anti-antibody response (human antichimeric antibody/human antimouse antibody). CONCLUSION These phase I/II data demonstrate that IDEC-Y2B8 radioimmunotherapy is a safe and effective alternative for outpatient therapy of patients with relapsed or refractory NHL. A phase III study is ongoing.

Phase II Trial of Single-Agent Temsirolimus (CCI-779) for Relapsed Mantle Cell Lymphoma

PURPOSE Mantle cell lymphoma (MCL) is characterized by a t(11;14) resulting in overexpression of cyclin D1 messenger RNA. This study tested whether temsirolimus (previously known as CCI-779), an inhibitor of the mammalian target of rapamycin kinase that regulates cyclin D1 translation, could produce tumor responses in patients with MCL. PATIENTS AND METHODS Patients with relapsed or refractory MCL were eligible to receive temsirolimus 250 mg intravenously every week as a single agent. Patients with a tumor response after six cycles were eligible to continue drug for a total of 12 cycles or two cycles after complete remission, and were then observed without maintenance. RESULTS Thirty-five patients were enrolled and were assessable for toxicity; one patient had MCL by histology but was cyclin D1 negative and was ineligible for efficacy. The median age was 70 years (range, 38 to 89 years), 91% were stage 4, and 69% had two or more extranodal sites. Patients had received a median of three prior therapies (range, one to 11), and 54% were refractory to the last treatment. The overall response rate was 38% (13 of 34 patients; 90% CI, 24% to 54%) with one complete response (3%) and 12 partial responses (35%). The median time-to-progression in all patients was 6.5 months (95% CI, 2.9 to 8.3 months), and the duration of response for the 13 responders was 6.9 months (95% CI, 5.2 to 12.4 months). Hematologic toxicities were the most common, with 71% (25 of 35 patients) having grade 3 and 11% (four of 35 patients) having grade 4 toxicities observed. Thrombocytopenia was the most frequent cause of dose reductions but was of short duration, typically resolving within 1 week. CONCLUSIONS Single-agent temsirolimus has substantial antitumor activity in relapsed MCL. This study demonstrates that agents that selectively target cellular pathways dysregulated in MCL cells can produce therapeutic benefit. Further studies of this agent in MCL and other lymphoid malignancies are warranted.

Serum Cardiac Troponins and N-Terminal Pro-Brain Natriuretic Peptide: A Staging System for Primary Systemic Amyloidosis

PURPOSE Primary systemic amyloidosis (AL) is a multisystemic disorder resulting from an underlying plasma cell dyscrasia. There is no formal staging system for AL, making comparisons between studies and treatment centers difficult. Our group previously identified elevated serum cardiac troponin T (cTnT) as the most powerful predictor of overall survival. Others have reported that N-terminal pro-brain natriuretic peptide (NT-proBNP) is a valuable prognostic marker. We sought to develop a staging system for patients with AL. PATIENTS AND METHODS Two hundred forty-two patients with newly diagnosed AL who were seen at the Mayo Clinic between April 1979 and November 2000, and who had echocardiograms and stored serum samples at presentation were eligible for this retrospective review. NT-proBNP measurements were performed on 242 patients in whom cTnT and cardiac troponin I (cTnI) had been previously run. Two prognostic models were designed using threshold values of NT-proBNP and either cTnT or cTnI (NT-proBNP < 332 ng/L, cTnT < 0.035 microg/L, and cTnI < 0.1 microg/L). Depending on whether NT-proBNP and troponin levels were both low, were high for only one level, or were both high, patients were classified as stage I, II, or III, respectively. RESULTS Using the cTnT+NT-proBNP model 33%, 30%, and 37% of patients were stages I, II, and III, respectively, with median survivals of 26.4, 10.5, and 3.5 months, respectively. The alternate cTnI+NT-proBNP model predicted median survivals of 27.2, 11.1, and 4.1 months, respectively. CONCLUSION Stratification of AL patients into three stages is possible with two readily available and reproducible tests setting the stage for more consistent and reliable cross comparisons of therapeutic outcomes.