Efficacy and safety of mogamulizumab by patient baseline blood tumour burden: a post hoc analysis of the MAVORIC trial

Background

Mogamulizumab was compared with vorinostat in the phase 3 MAVORIC trial (NCT01728805) in 372 patients with relapsed/refractory mycosis fungoides (MF) or Sézary syndrome (SS) who had failed ≥1 prior systemic therapy. Mogamulizumab significantly prolonged progression‐free survival (PFS), with a superior objective response rate (ORR) vs. vorinostat.

Objectives

This post hoc analysis was performed to evaluate the effect of baseline blood tumour burden on patient response to mogamulizumab.

Methods

PFS, ORR, time to next treatment (TTNT), skin response (modified Severity‐Weighted Assessment Tool [mSWAT]) and safety were assessed in patients stratified by blood classification (B0 [n = 126], B1 [n = 62], or B2 [n = 184], indicating increasing blood involvement).

Results

Investigator‐assessed PFS was longer for mogamulizumab versus vorinostat across all blood classes, significantly so for B1 and B2 patients. ORR was higher with mogamulizumab than with vorinostat in all blood classification groups and more markedly so with escalating B class (B0: 15.6% vs. 6.5%, P = 0.0549; B1: 25.8% vs. 6.5%, P = 0.2758; B2: 37.4% vs. 3.2%, P < 0.0001). TTNT was significantly longer for patients treated with mogamulizumab versus vorinostat with B1 (12.63 vs. 3.07 months; HR 0.32 [95% CI 0.16–0.67]; P = 0.0018) and B2 (13.07 vs. 3.53 months; HR 0.30 [95% CI 0.21–0.43]; P < 0.0001) blood involvement. In the mogamulizumab arm, 81 patients (43.5%) had ≥50% change in the mSWAT vs. 41 patients (22.0%) with vorinostat; mSWAT improvements with mogamulizumab occurred most often in B1 and B2 patients. Rapid, sustained reductions were seen in CD4⁺CD26^‐ cell counts and CD4:CD8 ratios in mogamulizumab patients for all B classes. Treatment‐emergent adverse events were less frequent overall with mogamulizumab and similar in frequency regardless of B class.

Conclusions

This post hoc analysis indicates greater clinical benefit with mogamulizumab vs. vorinostat in patients with MF and SS classified as having B1 and B2 blood involvement.

The use of basiliximab-infliximab combination for the treatment of severe gastrointestinal acute GvHD

After allogeneic stem cell transplant, severe grade III-IV gastrointestinal (GI) acute GvHD is associated with significant morbidity and mortality, and generally results in poor outcomes. Salvage therapy for patients who fail steroid therapy is not well defined in the literature. In the current retrospective study, we reviewed our experience with the combination of basiliximab and infliximab in 21 patients with severe, grade III-IV GI acute GvHD of whom 16 met the definition for steroid-refractory disease. The overall response rate was 76%, with 43% CR at a median time of 21 days after beginning treatment. The survival at 1 year was 24%, with most deaths due to complications from GvHD and recurrence of primary disease. All five of the long-term survivors have chronic GvHD. On the basis of a review of the literature, this regimen does not seem to be significantly more effective than other strategies for severe GI GvHD and seems to be worse than the results reported for basiliximab alone. Future studies of single-agent basiliximab and newer agents are required.

Utility of ¹⁸fluoro-deoxyglucose positron emission tomography for prognosis and response assessments in a phase 2 study of romidepsin in patients with relapsed or refractory peripheral T-cell lymphoma

BACKGROUND

For patients with peripheral T-cell lymphoma (PTCL), the value of (18)fluoro-deoxyglucose positron emission tomography (FDG-PET) scans for assessing prognosis and response to treatment remains unclear. The utility of FDG-PET, in addition to conventional radiology, was examined as a planned exploratory end point in the pivotal phase 2 trial of romidepsin for the treatment of relapsed/refractory PTCL.

PATIENTS AND METHODS

Patients received romidepsin at a dose of 14 mg/m(2) on days 1, 8, and 15 of 28-day cycles. The primary end point was the rate of confirmed/unconfirmed complete response (CR/CRu) as assessed by International Workshop Criteria (IWC) using conventional radiology. For the exploratory PET end point, patients with at least baseline FDG-PET scans were assessed by IWC + PET criteria.

RESULTS

Of 130 patients, 110 had baseline FDG-PET scans, and 105 were PET positive at baseline. The use of IWC + PET criteria increased the objective response rate to 30% compared with 26% by conventional radiology. Durations of response were well differentiated by both conventional radiology response criteria [CR/CRu versus partial response (PR), P = 0.0001] and PET status (negative versus positive, P < 0.0001). Patients who achieved CR/CRu had prolonged progression-free survival (PFS, median 25.9 months) compared with other response groups (P = 0.0007). Patients who achieved PR or stable disease (SD) had similar PFS (median 7.2 and 6.3 months, respectively, P = 0.6427). When grouping PR and SD patients by PET status, patients with PET-negative versus PET-positive disease had a median PFS of 18.2 versus 7.1 months (P = 0.0923).

CONCLUSIONS

Routine use of FDG-PET does not obviate conventional staging, but may aid in determining prognosis and refine response assessments for patients with PTCL, particularly for those who do not achieve CR/CRu by conventional staging. The optimal way to incorporate FDG-PET scans for patients with PTCL remains to be determined.

TRIAL REGISTRATION

NCT00426764.

Final results of a phase I study of oral belinostat (PXD101) in patients with solid tumors

3531

Background: Belinostat (Bel) is a histone deacetylase inhibitor with broad preclinical activity. IV Bel is well-tolerated with clinical activity at 1 g/m2 daily x5, q3w. Methods: Patients (pts) were treated with multiple schedules (see table) to assess safety, pharmacokinetics (PK) and efficacy. PK was done on day (d) 1 (fasting) and d7 (non-fasting) along with serial ECGs. Results: 92 pts, median age 60 (range 32–89) have been included. Major cancer types included colorectal (22%), prostate (17%), bladder (11%). Most frequent related adverse events (AEs), any grade (gr), were fatigue (53%), nausea (49%), anorexia (36%), vomiting (27%), diarrhea (25%). Only related gr 3/4 AE noted by more than 1 pt was fatigue. Hematological tox included gr 2: anemia (6 pts), leucopenia (2 pts), and thrombocytopenia (1 pt). Two events of gr 2 QTc prolongation were reported. Recommended dose (RD) for continuous dosing was determined as 250 mg, QD or BID, based on dose limiting toxicity (DLT; gr 3 if not indicated) seen in 2 pts in cohort 2A: dehydration and fatigue. Based on overall tolerability and DLTs (cohort 2C fatigue; 3C gr 2 nausea/vomiting/diarrhea; 4C atypical chest pain, elevated creatinine; 2D atrial fibrillation, hypokalemia, fatigue) the RD for d1–14 dosing was determined as 750 mg QD, with option for intra-pt dose escalation if limited tox. For d1–5 dosing, evaluation of the highest dose-cohort is not finalized; 1 pt had gr 3 psychosis, but also experienced same event 16d after treatment stopped. Exposure of Bel in plasma correlates with dose; PK on d1/d7 indicate a possible effect of food. To date, 33 pts (41%) have SD; 5 pts ≥6 months (d on treatment: 710 adenoidcystic, +488 bladder, 485 renal, 196 rectal, 182 prostate), and 12 pts 3–6 months. Conclusions: Oral Bel can be delivered safely with multiple schedules. The safety profile and long stabilizations in multiple tumor types makes Bel an interesting option for further evaluation as a monotherapy and in combination with chemotherapy.

[Table: see text]

[Table: see text]

Long-term treatment of CTCL with the oral PNP inhibitor, forodesine

8552

Background: Forodesine is a potent inhibitor of purine nucleoside phosphorylase (PNP) that leads to T-cell selective intracellular accumulation of dGTP, resulting in apoptosis. Methods: An open-label dose escalation study of oral forodesine (40–320 mg/m2 daily) for 4 wks with extended therapy was performed to determine the maximum tolerated and/or optimal biologic dose (OBD). Additional subjects were accrued at an OBD (80 mg/m2) to further assess safety and clinical efficacy. Subjects with refractory CTCL, stages IB-IV were eligible. The primary efficacy endpoint (objective response rate [ORR]) was defined as ≥ 50% improvement by a severity-weighted assessment tool (mSWAT). Results: The overall intent to treat response rate was 17 of 64 (27%) subjects or 14 of 36 (39%) at the OBD. As of October 2008, nine of 64 subjects (14%) have received forodesine treatment for >12 months. This cohort of 9 subjects is further examined. Six discontinued treatment (median time on treatment 440 days): 4 for progressive disease, 1 withdrew consent, and 1 due to an adverse event (Diffuse Large B-cell Lymphoma). Three are continuing on therapy for 416, 710, and 863 days. Median age was 68 years (range 42, 81), and all but one was ≥ stage III. They had received a median of 3 prior systemic therapies including 8 of 9 with prior bexarotene. Five of 9 subjects had a response (2 with complete response, 3 with partial response, and 4 with stable disease). Related AEs were experienced by 7 of 9 subjects. The most frequent were nausea (44%), fatigue, peripheral edema, dyspnea, and urinary casts (all 22%). Grade 3 or higher related AEs were experienced by 2 of 9 subjects (Diffuse Large B-Cell Lymphoma as previously mentioned and peripheral edema). There were no hematologic or infection AEs related to forodesine. Grade 3 lymphopenia and CD4 count < 200 were noted in 8 of 9 and 4 of 9 subjects respectively. The risk of any infection AE regardless of cause in these 9 subjects was 15 per 100 person-months of forodesine exposure compared to 59 in all other subjects (n=55). Conclusions: Forodesine has an acceptable safety profile and efficacy in these CTCL subjects treated for 12 months or longer.

[Table: see text]

Final results of a phase I study of oral belinostat (PXD101) in patients with lymphoma

8580

Background: Belinostat (Bel) is a histone deacetylase inhibitor with broad preclinical activity. A phase I of oral Bel in patients (pts) with solid tumors found a recommended dose for day (d) 1–14, q3w, of 750 mg QD, with option for intra-patient dose escalation if limited toxicity. The current study was initiated to assess if the same dose could be utilized in pts with lymphoma. Methods: Objectives included safety and efficacy of oral Bel in cohorts of 3–6 pts (A 750; B 1000; C 1250; mg QD) treated d 1–14, q3w. Pts with relapsed/refractory non-Hodgkin lymphoma (NHL) or Hodgkin's disease (HD) with evaluable disease and acceptable organ functions were eligible. Dose limiting toxicity (DLT) assessed in cycle 1 included: related non-hem grade (gr) 3/4 tox; gr 4 neutropenia > 5 d or with fever > 100.5 °F; gr 4 thrombocytopenia > 7 d. Results: 9 pts (3 per cohort), median age 51 (range 21–92), median 5 (range 2–7) prior regimens (83% had BM transplants, including 1 pt with allogeneic) have been enrolled. Diagnoses include mantle cell lymphoma (MCL; 4 pts), HD (3 pts), other NHL (2 pts). Most frequent adverse events (regardless of attribution or gr) in 7 pts fully evaluable for tox: anorexia (7 pts), fatigue, (6 pts), diarrhea (6 pts), and constipation, fever, and cough (each in 3 pts). Non-hem gr 3 events (no gr 4 noted): diarrhea (1 pt each in cohorts A and B, both in cycle 2), fatigue, anorexia, and leg DVT (each in 1 pt; all after cycle 1). One gr 3, and 1 gr 4 (from baseline gr 2; duration gr 4 <7 d) thrombocytopenia were seen in cohort C. In 6 pts evaluable for efficacy, stable disease have been noted in 5 pts for 3 to +7 cycles, including 3 of 3 pts (one refractory) with MCL and 2 of 2 pts (both refractory) with HD. Tumor shrinkage of 43 to 49% have been found in 1 HD and 2 MCL pts after cycle 2. Conclusions: Oral Bel can be delivered safely with a d 1–14, q3w schedule in pts with lymphoma at a daily dose higher than what has been established for pts with solid tumors. No protocol defined DLTs have yet been encountered in the dose range 750 to 1250 mg QD in pts with lymphoma. Final evaluation will include additional pts and possible dose escalation. The safety profile and early tumor shrinkage noted in MCL and HD warrants continued evaluation of Bel, especially in combination with other active compounds.

[Table: see text]

Autologous and allogeneic transplantation for aggressive T-cell lymphomas: A single institution experience

8558

Aggressive T-cell lymphomas (ATCL) represent 10–15% of non-Hodgkin lymphoma and have a worse prognosis than aggressive B-cell lymphomas. Both autologous (Auto) and allogeneic (Allo) stem cell transplantation have been used as consolidation in first remission and at relapse, but the role of transplantation has not been clearly defined. There were 24 Auto and 18 Allo between 8/1997 and 12/2007. The Allo group consisted of 4 PTCLu, 3 angioimmunoblastic(AITL), 2 panniculitis-like, 2 cutaneous(CTCL) with large cell transformation, 2 NK-cell, 2 anaplastic large cell(ALCL), 1 hepatosplenic, 1 enteropathic, and 1 refractory CTCL. The Auto group consisted of 6 PTCLu, 12 ALCL (5 Alk+, 5 Alk-, 2 Alk unk), 4 AITL, 1 CTCL with transformation, and 1 T-lymphoblastic lymphoma. The median age was 51y(Allo) and 52y(Auto). Median prior therapies were 3(Allo) and 1(Auto). There were 14 matched- and 4 matched-unrelated Allo transplants; 7 were ablative and 11 were reduced-intensity. Median time from diagnosis to Allo or Auto was 18 and 8mo, respectively. Median follow-up was 29mo (Allo) and 24mo (Auto). The day 100 TRM was 11%(Allo) and 4%(Auto) respectively. The relapse mortality was 11%(Allo) and 33%(Auto). The non-relapse mortality was 33%(Allo) and 8%(Auto). The 1- and 2-year overall survival(OS) rates were similar within the Allo and Auto groups (78% vs 74%, and 67% vs 60% respectively). The 1- and 2-year progression-free survival (PFS) for the Allo vs Auto groups were 68% vs 52%, and 53% vs 45%, respectively (p=0.28). Within the Auto group, 14(58%) were transplanted in first complete remission(CR1), and 10(42%) in CR2, beyond CR2, or PR. Patients in CR1 had significantly better PFS (57 vs 17mo, p=0.007) and OS (76 vs 29mo, p=0.004) than those in CR2, beyond CR2, or PR. Allo patients with prior Auto(6) had a poorer OS than patients with no prior Auto(12), 32 vs 60mo, respectively, but the results were not statistically significant, p=0.15. One Allo was transplanted in CR1 and is still alive at 33mo. We conclude that outcomes for Auto are best in CR1. For patients with resistant or relapsed disease, Allo should be strongly considered rather than Auto. These results also suggest that a prospective randomized trial comparing Auto and Allo for ATCL in first remission is warranted.

No significant financial relationships to disclose.

Vorinostat (suberoylanilide hydroxamic acid, SAHA) is clinically active in advanced cutaneous T-cell lymphoma (CTCL): Results of a phase IIb trial

7500

Background: Vorinostat is a histone deacetylase inhibitor that has demonstrated clinical activity at tolerable dose levels in patients (pts) with advanced CTCL in phase I and IIa trials. Methods: Open-label, single-arm, nonrandomized phase IIb trial of oral vorinostat 400 mg daily until disease progression or intolerable toxicity. Eligibility: advanced CTCL; ≥ 2 prior systemic therapies which must have included bexarotene unless unable to tolerate; adequate hematologic, hepatic and renal function. Planned sample size: ≥ 50 evaluable pts with clinical stage ≥ IIB. Primary endpoint: objective response rate (OR = CR + PR) as measured by a modified skin severity weighted assessment tool. The study would be positive if OR in ≥ stage IIB pts was ≥ 20%. Secondary endpoints: assessment of response duration (DOR), time to progression (TTP), time to response (TTR), pruritus relief and safety. Results: Seventy-four pts (median age, 60 y [range, 39–83]; median 3 prior systemic therapies) were enrolled (61 pts ≥ stage IIB) from 9/04 to 5/05 at 18 centers. Data cut-off was 11/05 with a median follow-up of 4 months. Efficacy data are shown in Table 1 . The OR was 29.5% (18 PR including 1 with later CR) in ≥ stage IIB pts. Median TTP was 148 d for all pts and 203.5+ d for responders. The most common drug-related adverse experiences (AE) were diarrhea (49%), fatigue (46%), nausea (43%) and anorexia (26%), and were mostly ≤ Grade 2. Drug-related ECG changes were Grade 1 in 5 pts (7%) and Grade 2 in 1 pt (1%), but not associated with cardiac symptoms. Seven pts discontinued and 10 had dose modification due to drug-related AE. Drug-related AE ≥ Grade 3 included fatigue (5%), pulmonary embolism (5%), nausea (4%) and thrombocytopenia (4%). Twenty-five pts discontinued due to progressive disease. Causes of the 3 deaths on study were: unknown (d 2), ischemic stroke (d 227) and disease progression (d 52). Conclusion: Oral vorinostat is effective in the treatment of advanced CTCL with an acceptable safety profile.

[Table: see text]

[Table: see text]

Identification of amplified clonal T cell populations in the blood of patients with chronic graft-versus-host disease: positive correlation with response to photopheresis

Chronic graft-versus-host disease (cGVHD) is a multiorgan disorder with skin manifestations resembling scleroderma. Since photopheresis, a treatment that induces an anticlonotypic immune response, has proven to be effective in both cutaneous T cell lymphomas with circulating clonal T cells and in cGVHD, we have searched for circulating clonal T cell populations in patients with cGVHD, and determined whether T cell clonality in the blood is associated with therapeutic response. We screened blood samples from 27 patients after HLA-matched allogeneic bone marrow transplantation (allo-BMT), 10 without cGVHD and 17 with extensive cGVHD, for clonal T cell receptor gamma (TCR gamma) gene rearrangements using fluorescent-based polymerase chain reaction (PCR) and automated high-resolution capillary electrophoresis. Amplified populations of clonal T cells with unique TCR gamma gene rearrangements were found in six of 10 (60%) allo-BMT patients without cGVHD and 13 of 17 (76.5%) allo-BMT patients with cGVHD (P = 0.41), as compared to none of 10 (0%) healthy controls. Twelve patients with cGVHD were treated by photopheresis, and the presence of amplified populations of clonal T cells was found to be associated with a cutaneous response to photopheresis, as eight of eight (100%) clone-positive vs none of four (0%) clone-negative patients experienced a clinically significant cutaneous response to treatment (P = 0.001). Our findings suggest that patients with cGVHD that have detectable expanded clonal T cell populations in their peripheral blood, may be more likely to respond to treatment by photopheresis.

The role for interleukin-12 therapy of cutaneous T cell lymphoma

Recent phase I and phase II trials using recombinant human interleukin-12 (rhIL-12) for cutaneous T cell lymphoma (CTCL) have been completed. Observations on 32 evaluable patients revealed an overall response rate approaching 50 percent. Biopsy of regressing lesions revealed an increase in numbers of CD8+ and/or TIA-1+ T cells. These results suggest that rhIL-12 may induce lesion regression by augmenting antitumor cytotoxic T cell responses. Future trials will be focused on strategies for further immune enhancement by the concomitant use of additional immune augmenting cytokines with rhIL-12.

Signaling from protease-activated receptor-1 inhibits migration and invasion of breast cancer cells

Proteases give cancer a defining characteristic of being able to break through extracellular matrix barriers and invade into other tissues in response to chemotactic signals. Recently, the cell surface protease-activated receptor (PAR)-1 has been shown to act as a chemokine receptor in inflammatory cells, and its expression is tightly correlated with metastatic propensity of breast cancer cells. The aim of the present study was to determine whether activation of PAR1 or the other known PARs (PAR2-4) can regulate migration and invasion of breast cancer cells. We found that the highly invasive MDAMB231 breast cancer cell line expressed very high levels of functional PAR1, PAR2, and PAR4, whereas minimally invasive MCF7 cells had trace amounts of PAR1 and low levels of PAR2 and PAR4. Despite the differences in expression, PAR2 and PAR4 acted as chemokine receptors in both invasive and minimally invasive breast cell lines. Quite unexpectedly, we found that activation of PAR1 with thrombin or the peptide agonist SFLLRN markedly inhibited invasion and migration of MDAMB231 cells when applied as a concentration gradient in the direction of cell movement. Additionally, we demonstrated that inhibition of chemotaxis was mediated through a G(i)/phosphoinositide-3-OH kinase-dependent pathway. Activation of G(i) signaling with epinephrine or wasp venom mastoparan also inhibited invasion and migration of the breast cancer cells. These findings suggest that therapeutics targeted toward G(i)-couplers that are selectively expressed in breast cancer cells could prove beneficial in halting the progression of invasive breast cancer.

Pivotal phase III trial of two dose levels of denileukin diftitox for the treatment of cutaneous T-cell lymphoma

PURPOSE

The objective of this phase III study was to determine the efficacy, safety, and pharmacokinetics of denileukin diftitox (DAB389IL-2, Ontak [Ligand Pharmaceuticals Inc, San Diego, CA]) in patients with stage Ib to IVa cutaneous T-cell lymphoma (CTCL) who have previously received other therapeutic interventions.

PATIENTS AND METHODS

Patients with biopsy-proven CTCL that expressed CD25 on > or = 20% of lymphocytes were assigned to one of two dose levels (9 or 18 microg/kg/d) of denileukin diftitox administered 5 consecutive days every 3 weeks for up to 8 cycles. Patients were monitored for toxicity and clinical efficacy, the latter assessed by changes in disease burden and quality of life measurements. Antibody levels of antidenileukin diftitox and anti-interleukin-2 and serum concentrations of denileukin diftitox were also measured.

RESULTS

Overall, 30% of the 71 patients with CTCL treated with denileukin diftitox had an objective response (20% partial response; 10% complete response). The response rate and duration of response based on the time of the first dose of study drug for all responders (median of 6.9 months with a range of 2.7 to more than 46.1 months) were not statistically different between the two doses. Adverse events consisted of flu-like symptoms (fever/chills, nausea/vomiting, and myalgias/arthralgias), acute infusion-related events (hypotension, dyspnea, chest pain, and back pain), and a vascular leak syndrome (hypotension, hypoalbuminemia, edema). In addition, 61% of the patients experienced transient elevations of hepatic transaminase levels with 17% grade 3 or 4. Hypoalbuminemia occurred in 79%, including 15% with grade 3 or 4 changes. Tolerability at 9 and 18 microg/kg/d was similar, and there was no evidence of cumulative toxicity.

CONCLUSION

Denileukin diftitox has been shown to be a useful and important agent in the treatment of patients whose CTCL is persistent or recurrent despite other therapeutic interventions.

Infectious complications of pentostatin therapy

Managing the infectious complications associated with pentostatin (Nipent), used alone or in combination with other agents in patients with low-grade lymphomas, poses a significant problem for clinicians. Since there is limited experience with these therapies, definitive treatment recommendations concerning prophylaxis cannot be made. The panel members discussed the use of valacyclovir (Valtrex) to provide prophylaxis for herpes zoster, trimethoprim/sulfamethoxazole for Pneumocystis, and acyclovir (Zovirax) for varicella zoster. They also considered combinations of pentostatin with agents such as interferon, rituximab (Rituxan), and chlorambucil (Leukeran) and their effect on the immune system. The biology of B and T cells was discussed, with an emphasis on clinical application.

Isolation and characterization of NUC70, a cytoplasmic, hematopoietic apoptotic endonuclease

Endonucleolytic DNA fragmentation is the common end point and the prevailing indicator of apoptosis. We have identified a 70-kDa endonuclease (NUC70) that is activated in drug-induced apoptosis of human hematopoietic cells. We purified NUC70 to homogeneity and generated a rabbit polyclonal antibody to distinguish it from previously identified nucleases. Biochemical characterization of isolated NUC70 demonstrates that it is Ca2+/Mg2+-dependent and active over a pH range of 6-8. When incubated with isolated HeLa nuclei, NUC70 was capable of generating internucleosomal DNA fragmentation. This endonucleolytic activity was inhibited by Zn2+, aurintricarboxylic acid, N-ethylmaleimide, spermine, and iodoacetamide. Western immunoblots using the anti-NUC70 antibody and DNA-SDS-polyacrylamide gel electrophoresis assays indicate that NUC70 expression and activity is restricted to human hematopoietic cells. No such activity was detected in human epithelial cell lines or murine hematopoietic cells. We also observed no difference in levels of NUC70 expression between apoptotic and nonapoptotic cells, suggesting that activation of NUC70 may be by posttranslational modification. We demonstrate that NUC70 activity is diminished in cells pretreated with the caspase inhibitors z-DEVD-fmk, z-VAD-fmk, and Z-CH2-Asp-DCB. Time course studies of cytoplasmic and nuclear endonuclease activities during apoptosis show that NUC70 is a cytoplasmic endonuclease that is translocated to the nucleus after the initiation of apoptosis. We confirmed this with immunostaining studies using anti-NUC70 antibody. These results demonstrate that NUC70 is an endogenous cytoplasmic endonuclease that is activated during apoptosis in a caspase-dependent mechanism.

Antitumor activity of DAB389IL-2 fusion toxin in mycosis fungoides

BACKGROUND

DAB389IL-2 is a novel fusion toxin that retargets the cytotoxic A-chain of diphtheria toxin to interleukin-2 (IL-2) receptor-expressing tumors.

OBJECTIVE

The purpose of this phase I trial was to study the toxicity, maximum tolerated dose, and clinical efficacy of DAB389IL-2 in IL-2 receptor expressing lymphoproliferative malignancies, including cutaneous T-cell lymphoma.

METHODS

DAB389IL-2 was administered intravenously daily for 5 days every 3 weeks. Dose escalation occurred between patient groups. Patients were monitored for laboratory and clinical toxicity, kinetics, immune response, and clinical efficacy.

RESULTS

Thirty-five patients with cutaneous T-cell lymphoma (including 30 patients with mycosis fungoides) were treated. Previously, conventional therapy had not worked for 34 of the patients. Thirteen patients (37%) achieved an objective response, including a complete response in five patients (14%). Complete response was achieved in patients with extensive erythroderma and tumor stage mycosis fungoides. Adverse events consisted of reversible fever/chills, hypotension, nausea/vomiting, and elevation of hepatic transaminase. Doses of less than 31 microg/kg per day were well tolerated. Clinical responses were observed at all dose levels.

CONCLUSION

DAB389IL-2 is well tolerated at doses of less than 31 microg/kg per day, and it induced clinical responses in previously treated mycosis fungoides, providing evidence for the antitumor activity of this molecule.

Phase I trial of a ligand fusion-protein (DAB389IL-2) in lymphomas expressing the receptor for interleukin-2

The purpose of this study was to evaluate the safety, tolerability, pharmacokinetics, and possible antitumor activity of a ligand fusion-protein, DAB389IL-2, in a phase I trial. This was a multicenter, open-label, dose-escalation trial. Patients with preserved organ function and histologically confirmed relapsed cutaneous T-cell lymphoma (CTCL), other non-Hodgkin's lymphomas (NHL), or Hodgkin's disease (HD) were eligible if their cancer was shown to express the interleukin (IL)-2 receptor by an immunohistochemical assay for the p55 or the p75 subunit. Patients received up to eight courses of DAB389IL-2 given as a short intravenous infusion daily for 5 days with subsequent courses every 21 days. The maximum tolerated dose (MTD) and tumor response was determined according to standard criteria. Seventy-three patients (44 men/29 women), aged 16 to 81 years (mean, 50.7) with CTCL (n = 35), NHL (n = 17), and HD (n = 21) were enrolled. The patients were extensively treated, failing 0 to 15 previous therapies (median, 4). Patients received one to six courses (mean, 3.3) of DAB389IL-2 over a range of 3 to 31 micrograms/kg/day. The dose-limiting toxicity was asthenia, establishing the maximum tolerated dose of 27 micrograms/kg/day. Approximately half of all patients had significant titers of antibody to diphtheria toxin or to DAB389IL-2 at the time of enrollment compared with 92% with titers at the end of treatment. The presence of antibody did not preclude clinical response. There were five complete (CR) and eight partial (PR) remissions in patients with CTCL with one CR and two PR occurring in NHL. The median time to response was 2 months and the duration of response was 2 to 39+ months. No responses were documented in patients with HD. DAB389IL-2 is well tolerated with an MTD of 27 micrograms/kg/day. This ligand fusion-protein showed antitumor effects in patients with IL-2 receptor expressing CTCL and NHL. Additional trials in these diseases are warranted.

Interleukin-2 fusion protein: an investigational therapy for interleukin-2 receptor expressing malignancies

DAB389IL-2 is an interleukin-2 receptor (IL-2R) specific fusion protein with a molecular weight of 58 kD containing the enzymatic and translocation domains of diphtheria toxin (DT) and human IL-2. This fusion protein is able to direct the cytocidal action of the DT enzymatic region only to cells which bear the IL-2R. The human IL-2R exists in three forms: low, intermediate and high affinity. The high-affinity form is believed to be the biologically relevant form on mature, activated T-lymphocytes, B-lymphocytes and monocytes. DAB389IL-2 is able to bind selectively to the high-affinity IL-2R in a concentration-dependent manner, and once bound is internalised via receptor-mediated endocytosis. Upon acidification of the formed vesicle, the enzymatic portion of the fusion protein is believed to pass into the cytosol where it ultimately inhibits protein synthesis by inactivation of elongation factor-2, resulting in cell death. The constitutive expression of the IL-2R on certain leukaemic and lymphomatous cells of T and B cell origin has been reported to occur in patients with chronic lymphocytic leukaemia, cutaneous T cell lymphoma (CTCL), Hodgkin's disease and non-Hodgkin's lymphomas (NHLs). A multicentre DAB389IL-2 dose-escalation study of patients with IL-2R expressing lymphomas has been conducted. A 10-fold range of doses were evaluated on a five-daily dose schedule. Patients received up to six courses, with an additional two courses permitted for patients with partial responses that appeared to be still improving after six courses. Most adverse experiences were transient and mild. Preliminary assessment of response indicated five complete responses (CR, duration ongoing at 20, 11, 7, 5 and 4 months) and seven partial responses (PR, duration 3-20 months) in the 35 patients with CTCL. One CR (duration > 20 months) in a patient with NHL (Lennett's lymphoma) and two PR (duration 9 and 2 months) in 17 patients with B-cell NHL have been observed. Based on the mode of action of DAB389IL-2, its safety profile, and the patient responses associated with the phase I/II clinical trials, a phase III programme in CTCL patients has been initiated and plans for additional trials in NHL patients are targeted for 1996.

Immunophenotypic identification of Sezary cells in peripheral blood

Despite anecdotal literature that Sezary cells express the CD4+ CD7- immunophenotype, no formal validation has been published establishing the use of this immunophenotype for clinical or experimental purposes. Consequently, the only method presently available for Sezary cell identification is nuclear contour analysis, a labor-intensive procedure not generally available at most major medical centers. In this study, the accuracy of CD4+ CD7- subset quantitation for the identification of Sezary cells was examined. The study found that the percentage of CD4+ CD7- cells is elevated in many Sezary syndrome/MF patients relative to normal, healthy individuals. In addition, CD4+ CD7- enumeration correlates with enumeration by nuclear contour analysis in most patients (11 of 15) with elevated CD4/CD8 ratios. The CD4+ CD7- subset also correlates with the expression of other aberrant immunophenotypes, such as CD3low or CD4low. Lastly, CD4+ CD7- subset quantitation correlates with the number of clonal T lymphocytes, as measured using V beta-specific T-cell receptor monoclonal antibodies. The study found this method to be exceptionally accurate, with two caveats: (1) the absence of an expanded CD4+ CD7- subset in patients with a normal CD4/CD8 ratio is uninformative; and (2) in approximately 25% of patients with an elevated CD4/CD8 ratio, the Sezary cells are CD7+.

Effect of DNA conformation on cisplatin adduct formation

The anticancer drug cis-diamminedichloroplatinum(II) (cisplatin) has been shown previously to form adducts preferentially within internucleosomal or linker DNA rather than to DNA within the nucleosome. To determine whether other "open" regions of chromatin have an increased affinity for cisplatin, adduct formation within specific chromatin domains was analyzed. There was a significant increase in cisplatin-DNA adduct formation for DNA associated with the nuclear matrix (NM) compared with other chromatin domains and total unfractionated DNA. In contrast, treatment of the same cells with trans-diamminedichloroplatinum(II) (transplatin) did not result in preferential adduct formation. These findings led to the hypothesis that it might be possible to alter DNA to make it a more favorable target for cisplatin. The effect of arginine butyrate on cisplatin-DNA adduct formation was analyzed in human cancer cells. The combination of arginine butyrate and cisplatin resulted in a concentration-responsive increase in cisplatin-DNA adduct formation in PC-3 cells and an overall increase in cisplatin-DNA adduct formation in three other human cancer cell lines. The same combination also resulted in a significant increase in drug-induced cytotoxicity at a low concentration of cisplatin. These results suggest that chromatin configuration can affect cisplatin adduct formation.

Rearrangement and altered expression of the NFKB-2 gene in human cutaneous T-lymphoma cells

The NF-kappa b/Rel and I kappa B proteins are important regulators of lymphocyte activation and gene expression. We have identified a rearrangement of the NFKB-2 gene in the HUT 78 human cutaneous T-cell leukemia (CTCL) line, cDNA and genomic DNA sequence predicted the presence of a truncated 80 kD NFKB-2 precursor protein (p80HT), instead of the normal p100 protein. No wild-type allele was identified. Elevated levels of two aberrantly sized RNAs were detected, and high levels of p80HT and processed p52 protein were present in HUT 78 cell nuclei. The p52 protein bound to a palindromic kappa B DNA motif, however p80HT did not. Rearrangement of the NFKB-2 gene was also detected in DNA from two patients with CTCL. Rearrangement and overexpression of the NFKB-2 gene may contribute to the genesis of a subset of T-cell malignancies.

Modulation of the expression of a multidrug resistance gene (mdr-1/P-glycoprotein) by differentiating agents

Acquired resistance to multiple natural products in vitro is mediated by P-glycoprotein (Pgp). Expression of this protein has been demonstrated in some normal tissues and in tumor samples obtained from both untreated and treated patients. In situ hybridizations with RNA probes have demonstrated higher levels of expression of mdr-1/Pgp in well-differentiated tumors and in well-differentiated areas in tumors with mixed histologies. Expression of mdr-1/Pgp in human colon carcinoma cell lines was increased by the differentiating agents sodium butyrate, dimethyl sulfoxide, and dimethylformamide. In the SW-620 cell line addition of sodium butyrate resulted in a rapid induction of mdr-1/Pgp mRNA that was sustained for the duration of the exposure. The levels of P-glycoprotein were measured by immunoblotting and were also increased. Similar results were obtained in three other cell lines including the HCT-15 line. This induction occurred without alterations in nuclease sensitivity. Discontinuation of sodium butyrate was followed by a rapid fall in the levels of mRNA. The levels of P-glycoprotein returned to normal with a half-life of about 24 h. In spite of a 20-25-fold increase in the level of mdr-1/Pgp mRNA and P-glycoprotein, the SW-620 cell line did not demonstrate increased resistance to doxorubicin and vinblastine or decreased accumulation of vinblastine. In contrast, in the HCT-15 cell line, a 5-fold increase of mdr-1/Pgp was accompanied by a comparable fall in vinblastine accumulation which was reversed by verapamil. In the SW-620 cell line, the induced protein could be photolabeled using [3H]azidopine. Expression of mdr-1/Pgp appears to correlate with the degree of differentiation. However, its induction is not always accompanied by expression of the multidrug-resistance phenotype.

Interposed abdominal compression-CPR: its effects on parameters of coronary perfusion in human subjects

Recent literature has emphasized the relationship between coronary perfusion during CPR and the success of resuscitation from prolonged arrest. In this study, aortic and right atrial pressures were monitored simultaneously during modifications of CPR. Three parameters associated with survival or coronary blood flow during CPR were measured: diastolic arterial pressure (DAP), diastolic arteriovenous difference (DAVD), and mean AV difference (MAVD). Standard advanced cardiac life support protocol was used although vasopressors were given by continuous infusion. In a series of two-minute trials, standard CPR, interposed abdominal compression (IAC) CPR, high-compression force (HCF) IAC-CPR, and HCF standard CPR were performed, with each patient serving as his own control. The DAP increased from 25 mm Hg during standard CPR to 43 during IAC CPR (P less than .001) and 50 during HC-IAC-CPR (P less than .001). The MAVD increased from 4 to 8 mm Hg during HCF-IAC-CPR (P less than .05). IAC-CPR had inconsistent effects on the DAVD. Three patients had a return of spontaneous circulation during the modifications of CPR after a mean of 43 minutes of asystole with standard CPR. In the seven autopsied patients, no significant abdominal injury was found. All forms of CPR studies produced DAVD in the majority of patients well below the minimum DAVD needed for resuscitation in animal models of prolonged arrest. Although the interposed abdominal compression seems to offer some advantages over standard CPR, these hemodynamic data suggest that it would be unlikely to improve survival rates appreciably.

Application of RNA-RNA tissue in situ hybridization in an analysis of a patient with leukemia

RNA-RNA tissue in situ hybridization is a relatively new technique that detects gene expression in individual cells. In this report we compare and contrast the technique with conventional biologic analysis. We illustrate how this technique could function as a diagnostic tool by applying it to a 58-year-old man with a four-month history of lymphadenopathy and peripheral lymphocytosis. RNA-RNA tissue in situ hybridization performed on sections of one of this patient's lymph nodes and on cytospins of his peripheral blood demonstrated the presence of an apparent monoclonal population of B cells producing mu and lambda immunoglobulin (Ig) messages in the lymph node and peripheral blood as well as a T-cell population in the lymph node only. These results were corroborative and complementary to conventional DNA (Southern) and RNA (Northern) analyses. The data were consistent with the diagnosis of chronic lymphocytic leukemia (CLL). With the use of this technique, an intriguing pattern of cellular heterogeneity was observed within the mu-lambda population of cells in the lymph node. A subset of these cells appeared to express a much greater amount of immunoglobulin message and to cluster around the lymph node vessels. The combination of RNA-RNA in situ hybridization and routine histopathology has the potential for providing an additional dimension to tumor analysis.