Jean Nichols

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.

Results From a Pivotal, Open-Label, Phase II Study of Romidepsin in Relapsed or Refractory Peripheral T-Cell Lymphoma After Prior Systemic Therapy

PURPOSE Romidepsin is a structurally unique, potent class 1 selective histone deacetylase inhibitor. The primary objective of this international, pivotal, single-arm, phase II trial was to confirm the efficacy of romidepsin in patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). PATIENTS AND METHODS Patients who were refractory to at least one prior systemic therapy or for whom at least one prior systemic therapy failed received romidepsin at 14 mg/m(2) as a 4-hour intravenous infusion on days 1, 8, and 15 every 28 days. The primary end point was the rate of complete response/unconfirmed complete response (CR/CRu) as assessed by an independent review committee. RESULTS Of the 131 patients enrolled, 130 had histologically confirmed PTCL by central review. The median number of prior systemic therapies was two (range, one to eight). The objective response rate was 25% (33 of 130), including 15% (19 of 130) with CR/CRu. Patient characteristics, prior stem-cell transplantation, number or type of prior therapies, or response to last prior therapy did not have an impact on response rate. The median duration of response was 17 months, with the longest response ongoing at 34+ months. Of the 19 patients who achieved CR/CRu, 17 (89%) had not experienced disease progression at a median follow-up of 13.4 months. The most common grade ≥ 3 adverse events were thrombocytopenia (24%), neutropenia (20%), and infections (all types, 19%). CONCLUSION Single-agent romidepsin induced complete and durable responses with manageable toxicity in patients with relapsed or refractory PTCL across all major PTCL subtypes, regardless of the number or type of prior therapies. Results led to US Food and Drug Administration approval of romidepsin in this indication.

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.

Administration of DAB389IL-2 to patients with recalcitrant psoriasis: A double-blind, phase II multicenter trial

BACKGROUND Current therapies for recalcitrant psoriasis focus on immunoregulation and targeting of activated T-lymphocytes rather than keratinocytes. Previous studies with low doses of the lymphocyte-selective fusion protein DAB389IL-2 have shown benefit to patients with psoriasis. OBJECTIVE We examined the safety and efficacy of DAB389IL-2 in 41 volunteers receiving more frequent and higher doses than in a previous trial. METHODS Patients were randomized to receive either placebo or 5, 10, or 15 microg/kg daily of DAB389IL-2 intravenously for 3 consecutive days each week for 4 consecutive weeks with a subsequent 4-week observation period. RESULTS Of the placebo group, 17% (2 of 12) exhibited at least 50% improvement from baseline Psoriasis Area and Severity Index scores at the end of the study, whereas 24% of all treated patients (7 of 29) showed the same improvement. Overall, 3 of 12 (25%) patients given placebo as opposed to 12 of 29 (41%) patients treated with DAB389IL-2 improved to this same extent at some point during the study. The rate of improvement for treated patients was significantly greater than for placebo patients (p = 0.04; repeated measures ANOVA). Among treated patients, decreases in Psoriasis Area and Severity Index scores were paralleled by changes in the Physicians Global Assessment and the Dermatology Life Quality Index. Treatment in ten patients was discontinued because of adverse events. Flu-like symptoms were the most common with severity increasing at the two higher doses. Only one serious adverse event was reported. This occurred in a patient receiving 5 microg/kg daily who experienced vasospasm and a coagulopathy resulting in arterial thrombosis. CONCLUSION Our findings are consistent with the potential antipsoriatic activity of DAB389IL-2 demonstrated in an earlier study. However, DAB389IL-2 was less well tolerated at this dosing regimen, particularly at the highest dose, and it was too toxic at these doses and schedules to be considered in the routine treatment of psoriasis.

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), Hodgkins disease and non-Hodgkins 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 (Lennetts 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.

A high rate of durable responses with romidepsin, bortezomib, and dexamethasone in relapsed or refractory multiple myeloma

We report results from a study exploring the combination of romidepsin, bortezomib, and dexamethasone for the treatment of patients with multiple myeloma (MM) previously treated with > 1 prior therapy. The primary objective was to determine the maximum tolerated dose (MTD) of the combination using a novel accelerated dose-escalation schedule in patients with relapsed or refractory MM. The secondary objective was to determine overall response (OR), time to progression (TTP), and overall survival (OS). The MTD identified was bortezomib 1.3 mg/m(2) (days 1, 4, 8, and 11), dexamethasone 20 mg (days 1, 2, 4, 5, 8, 9, 11, and 12), and romidepsin 10 mg/m(2) (days 1, 8, and 15) every 28 days. Thrombocytopenia (64%) was the most common ≥ grade 3 hematologic toxicity. Peripheral neuropathy occurred in 76% of patients (n = 19) (≥ grade 3, 8%; 95% confidence interval [CI] 1%-26%). Maintenance romidepsin 10 mg/m(2) (on days 1 and 8 of a 28-day cycle) proved feasible, with 12 patients receiving a median of 7.5 cycles (range: 1-29). An OR (M-protein) of > minor response (MR) was seen in 18 of 25 patients (72%); 2 (8%) had complete remissions (CRs) and 13 (52%) had partial responses (PRs), including 7 (28%) with very good PRs (VGPRs). The median TTP was 7.2 (95% CI: 5.5-19.6) months, and the median OS was > 36 months. This regimen shows activity with manageable toxicity and warrants further evaluation. This trial was registered at www.clinicaltrials.gov as NCT00431990.

Diphtheria toxin fusion proteins.

Two different approaches have been undertaken to develop targeted biomolecules for therapeutics. The first was the construction of immunotoxins consisting of monoclonal antibodies chemically linked through a disulfide bond to a plant or bacterial toxin or radionuclide. Instability of the chemical conjugation of some of the earlier immunotoxins led to the concept of using protein engineering and recombinant DNA to assemble fusion genes combining the sequences for the enzymatically active and translocation domains of a toxin with those of a specific targeting ligand. From the outset, the prospect of using recombinant DNA methods to assemble the structural genes encoding bacterial toxin growth factor fusion toxins, or fusion proteins, offered significant advantages over chemical conjugation in the assembly of chimeric proteins. Most importantly, the fusion junction, or point at which the substitute receptor binding domain was linked to the toxin fragment, could be precisely determined. Expression of the fusion gene in recombinant Escherichia coli would then result in the synthesis of a single homogeneous gene product rather than the mixture of isomeric forms which result from the chemical conjugation process used in the generation of immunotoxins, thereby leading to a theoretically more uniform agent for clinical studies.

Romidepsin in peripheral and cutaneous T‐cell lymphoma: mechanistic implications from clinical and correlative data

Romidepsin is an epigenetic agent approved for the treatment of patients with cutaneous or peripheral T‐cell lymphoma (CTCL and PTCL). Here we report data in all patients treated on the National Cancer Institute 1312 trial, demonstrating long‐term disease control and the ability to retreat patients relapsing off‐therapy. In all, 84 patients with CTCL and 47 with PTCL were enrolled. Responses occurred early, were clinically meaningful and of very long duration in some cases. Notably, patients with PTCL receiving romidepsin as third‐line therapy or later had a comparable response rate (32%) of similar duration as the total population (38%). Eight patients had treatment breaks of 3·5 months to 10 years; in four of six patients, re‐initiation of treatment led to clear benefit. Safety data show slightly greater haematological and constitutional toxicity in PTCL. cDNA microarray studies show unique individual gene expression profiles, minimal overlap between patients, and both induction and repression of gene expression that reversed within 24 h. These data argue against cell death occurring as a result of an epigenetics‐mediated gene induction programme. Together this work supports the safety and activity of romidepsin in T‐cell lymphoma, but suggests a complex mechanism of action.

Clinically meaningful reduction in pruritus in patients with cutaneous T-cell lymphoma treated with romidepsin

Abstract Patients with cutaneous T-cell lymphoma (CTCL) frequently experience severe pruritus that can significantly impact their quality of life. Romidepsin is approved by the US Food and Drug Administration (FDA) for the treatment of patients with CTCL who have received at least one prior systemic therapy, with a reported objective response rate of 34%. In a phase 2 study of romidepsin in patients with CTCL (GPI-04-0001), clinically meaningful reduction in pruritus (CMRP) was evaluated as an indicator of clinical benefit by using a patient-assessed visual analog scale. To determine the effect of romidepsin alone, confounding pruritus treatments including steroids and antihistamines were prohibited. At baseline, 76% of patients reported moderate-to-severe pruritus; 43% of these patients experienced CMRP, including 11 who did not achieve an objective response. Median time to CMRP was 1.8 months, and median duration of CMRP was 5.6 months. Study results suggest that the clinical benefit of romidepsin may extend beyond objective responses.

Electrocardiographic effects of class 1 selective histone deacetylase inhibitor romidepsin

Romidepsin is a histone deacetylase inhibitor approved by the FDA for the treatment of patients with cutaneous or peripheral T‐cell lymphoma who have received prior systemic therapy. The objective of this analysis was to evaluate the potential QTc effects of romidepsin. Patients with advanced malignancy received 4‐h infusions of 14 mg/m2 romidepsin on days 1, 8, and 15 of a 28‐day cycle. In cycle 2, a subset of patients received 1‐h infusions of 8–12 mg/m2 romidepsin. Patients were administered antiemetics before each romidepsin dose and electrolyte supplementation as needed. Electrocardiogram readings were performed prior to antiemetic administration, prior to romidepsin administration, and at specified time points over the subsequent 24 h. Romidepsin exposure and heart rate were also assessed. In the electrocardiogram‐evaluable population, 26 patients received romidepsin at 14 mg/m2 over 4 h. The maximum mean increases from the preantiemetic baseline for QTcF and heart rate were 10.1 msec (upper 90% CI, 14.5 msec) and 18.2 beats per minute, respectively. No patient in this study had an absolute QTcF value >450 msec and only one patient had an increase from the preantiemetic baseline of >60 msec. There was a mild reduction in the PR interval and no meaningful changes in the QRS interval. Despite the use of QT‐prolonging antiemetics, treatment with romidepsin did not markedly prolong the QTc interval through 24 h. Increases in calculated QTc may have been exaggerated as a consequence of transient increases in heart rate.