Denileukin Diftitox Research Articles

Phase I Clinical Trial of Pembrolizumab + and Denileukin diftitox in Patients with Recurrent Solid Tumors Shows Promising Results

Results from an ongoing investigator-initiated Phase I clinical trial (NCT05200559) evaluating the safety and efficacy of a combined regimen of pembrolizumab* (Keytruda®; Merck & Co/MSD) + denileukin diftitox-cxdl** (E7777; Lymphir™; Citius Oncology) in patients with recurrent solid tumors, shows positive preliminary study results.

Novel Pharmacological Treatment Options of Steroid-Refractory Graft-versus-Host Disease

Background. Graft-versus-host disease (GVHD) is a potentially fatal complication of allogeneic hematopoietic stem cell transplant. The mainstay of treatment is corticosteroids, which are ineffective in 30–50% of cases. Steroid-refractory GVHD (SR-GVHD) confers a poor prognosis, with high mortality rates despite appropriate therapy. While there is no reliable treatment for SR-GVHD, a variety of novel therapeutic options are slowly emerging and have yet to be examined simultaneously. Objectives. This review evaluates the potential of novel therapeutic options, as well as their efficacy and safety, for the treatment of SR-GVHD. Study Design. The literature search was conducted in PubMed, Cochrane, and Embase, employing MeSH terms and keywords. The studies had to be prospective phases 1, 2, or 3. We excluded retrospective and nonoriginal studies. Results. While the only approved drug for acute GVHD is ruxolitinib with an impressive overall response rate of 73.2% and a complete response of 56.3%, several monoclonal antibodies and other agents are currently under investigation, offering promising results. These include anti-CD2, anti-CD147, IL-2 antagonist, a mixture of anti-CD3 and anti-CD7 antibodies, anti-CD25, monoclonal antibody to a4b7 on T-cells, anti-CD26, pentostatin, sirolimus, denileukin diftitox, infliximab, itacitinib, and alpha-1 antitripsin. However, the toxicities associated with these novel drugs need further investigation. For chronic GVHD, approved options include ruxolitinib with an ORR of up to 62%, ibrutinib with an ORR of up to 77%, and belumosudil with an ORR of up to 77%. Meanwhile, emerging treatments include tyrosine kinase inhibitors such as nilotinib, rituximab, and low-dose IL-2, as well as axatilimab and pomalidomide. Conclusion. While their efficacy needs to be better evaluated through large-scale, multicenter, randomized clinical trials, these novel agents show potential and could provide a better alternative for SR-GVHD treatment in the future.

Targeting regulatory T cells by E7777 enhances CD8 T-cell-mediated anti-tumor activity and extends survival benefit of anti-PD-1 in solid tumor models.

Regulatory T cell (Treg)-targeting cancer immunotherapy aims to transiently deplete Treg cells in the tumor microenvironment, without affecting effector T cells (Teff), thus both enhancing anti-tumor activity and avoiding autoimmunity. This study evaluated whether adding E7777 (a new formulation of denileukin diftitox [DD]) improved the efficacy of anti-PD-1 antibody therapy. DD is a recombinant protein containing the hydrophobic and catalytic portions of diphtheria toxin fused to full-length human IL-2. E7777 has the same amino acid sequence and brief circulatory half-life as DD, but with greater purity and potency. Subcutaneous syngeneic murine solid tumor models (colon cancer CT-26 and liver cancer H22) were used to evaluate safety, efficacy, and overall survival with E7777 and anti-PD-1 antibodies, each administered as monotherapy or in concurrent or sequential combination. In Experiment 1, treatments were compared to assess anti-tumor activity at various time points, with tumors excised and dissociated and tumor leukocytes characterized. In Experiment 2, tumor growth, response, and overall survival were characterized for 100 days following a 3-week treatment. E7777 administered in combination with anti-PD-1 led to significantly increased anti-tumor activity and durable, extended overall survival compared to either treatment alone. In both tumor models, the Treg cell infiltration induced by anti-PD-1 treatment was counterbalanced by co-treatment with E7777, suggesting potential synergistic activity. Combination therapy showed the most favorable results. Treatment with E7777 was safe and well-tolerated. Combined E7777 and anti-PD-1 therapy was well tolerated and more effective than monotherapy with either drug.

CCR4-IL2 bispecific immunotoxin is more effective than brentuximab for targeted therapy of cutaneous T-cell lymphoma in a mouse CTCL model.

Cutaneous T-cell lymphoma (CTCL) encompasses two main subtypes: mycosis fungoides and Sezary syndrome. Global response rates for the systemic treatment of mycosis fungoides and Sezary syndrome are approximately 30% and none of these treatments are thought to be curative. C-C chemokine receptor type 4 (CCR4) and CD25 are encouraging targets for the treatment of CTCL and are individually targeted by mogamulizumab and denileukin diftitox, respectively. We developed a novel CCR4-IL2 bispecific immunotoxin (CCR4-IL2 IT) targeting both CCR4 and CD25. CCR4-IL2 IT demonstrated superior efficacy against CCR4+ CD25+ CD30+ CTCL in an immunodeficient NSG mouse tumor model. Investigative New Drug-enabling studies of CCR4-IL2 IT are ongoing, including Good Manufacturing Practice production and toxicology studies. In this study, we compared the in vivo efficacy of CCR4-IL2 IT versus the US Food and Drug Administration-approved drug, brentuximab, using an immunodeficient mouse CTCL model. We demonstrated that CCR4-IL2 IT was significantly more effective in prolonging survival than brentuximab, and combination treatment of CCR4-IL2 IT and brentuximab was more effective than brentuximab or CCR4-IL2 IT alone in an immunodeficient NSG mouse CTCL model. Thus, CCR4-IL2 IT is a promising novel therapeutic drug candidate for CTCL treatment.

An electrochemiluminescence assay for quantification of Denileukin Diftitox and its anti-drug antibodies in rat serum

Denileukin Diftitox (DD), comprising fragments of diphtheria toxin (DT) and interleukin-2 (IL2), was developed for the treatment of lymphoma and has been approved for marketing in Japan. Toxicological evaluation including pharmacokinetics and immunogenicity in preclinical animals is important for drug development and thus the assays of DD and anti-drug antibody (ADA) were developed by electrochemiluminescence (ECL) detection. For the DD assay, ruthenium-labeled anti-DT Ab and biotinylated anti-IL2 Ab were mixed with serum samples and the mixture was captured by streptavidin-coated wells for ECL detection. For the ADA assay, signals of immuno-complex of biotinylated DD, ruthenium-labeled DD, and ADA, bound to streptavidin plate were determined. DD was quantifiable from 10 ng/mL. Accuracy and precision of quality control samples were within ±20% and 20%, respectively, and stability of DD in rat serum was successfully assessed. Precision of positive control samples of ADA was within the acceptance criteria and cut point values for ADA detection in the screening and confirmatory assay were determined by statistical analysis. Drug-induced ADA was detected by screening assay followed by confirmatory assay. The developed method was successfully applied to assess pharmacokinetics and immunogenicity to support toxicity studies in rats.

Efficacy of Combinatorial Treatment Approaches in CTCL

BACKGROUND. Mycosis fungoides/Sezary syndrome (MF/SS) are the most common subtypes of cutaneous T cell lymphoma. The patients (pts) with early-stage MF usually have an indolent course and are managed with skin directed therapies. In contrast, pts with advanced-stage disease, have poor prognosis and a median overall survival between 2 and 5 years. Over the past 20 years only six novel biological/targeted agents (bexarotene, denileukin diftitox, vorinostat, romidepsin, brentuximab vedotin, mogamulizumab) have been FDA approved for systemic therapy of relapsed/refractory MF/SS however, none render curative approach. Overall response rate across all agents is 30% with CR rate of only 10%. Classical chemotherapy has no advantage over less toxic novel targeted agents in MF/SS. The head-to-head comparison of active therapeutic agents in prospective randomized trials is mostly absent and systemic therapy sequencing strategies are usually derived from personal experience, expert opinion, or retrospective reviews. The biomarkers directing the selection of targeted agents for individual patients are not available or reliable. In this study, we tested sensitivity of autologous lymphoma cells obtained from peripheral blood to various therapeutic agents and combinations ex vivo, in order to predict response to tested agents in vivo and develop more sophisticated, personalized, cost-effective, and clinical approach for treatment of pts with advanced stage MF/SS. METHODS. A 384-well plate is coated with poly-L-ornithine to help anchor the cells and the CTCL cells collected from the patients at Moffitt Cancer Center are thawed and incubated over-night at 37C. The next day, isolated CTCL cells are stained with CytoLight Rapid Green Reagent from Essen Bioscience. Once the dye is neutralized and washed out from the cells CytoxRed from Essen Bioscience is added to the media with cells. The cells are then distributed in a 384-well plate. Next, the drugs are diluted and added to the plate. There is a 5-time serial dilution of the drug and if it is a drug combination, one drug is serial diluted and the second drug is constant. After plating, the cells are incubated at 37C for 30min to let them rest and equilibrate. The EVOS M7000 (Life Technologies) is used using the GFP and Texas Red cubes to detect live (green) and dead (red) cells at 0h, 6h, 12h, 18h and 24h. When analyzing the data, the Celleste 5 (Life Technologies) program is used, specifically the Live/Dead application. The intensity threshold is kept constant throughout the entire experiment. The total number of live cells are used to calculate the viability of the cells at each time point. All the time points are done in triplicates and media with DMSO is used as the control. RESULTS. Out of 11 MF/SS pts samples treated with single agent and/or combinatorial drugs, 4 pts samples had no appreciable responses to single or combination treatments. In this study, response to treatment is deemed favorable if there is a decrease of 50% or more in viable cells in the course of the experiment. Seven pts samples did have responses against either a single drug or a combination of drugs. Out of the 7 pts that did respond, the most prevailing treatment was the combination of Venetoclax and Duvelisib with 6 out of 7 pts samples having a response to this combination. The next noteworthy response was seen with Romidepsin alone in 4 out of 7 pts. CONCLUSION. Our observations on MF/SS pts samples thus far demonstrates various sensitivities to treatments for individual pts. This may account for genetic and epigenetic changes which highlight the unmet need for personalization of treatment and sensitivity screening for each patient, with the decisive goal to offer a personalized and efficacious treatment modalities.

Gene Expression Profiling and Signaling Pathway Analysis of Tolerant T Cells Circulating in Adult Patients after Ptcy Haplotransplantation

The mechanisms of T cell-dependent tolerance, especially its signaling pathways after haploidentical hematopoietic stem cell transplantation (haplo-HSCT), are incompletely understood. Both central and peripheral regulation mechanisms are suspected. Subjects and Methods: We tested 8 patients with leukemia (5) or myelodysplastic syndromes (MDS, 3) (age 35-73-years old, median: 51-years old) following IRB approved consenting. All received Flu+TBI (+/- Cy) pre-conditioning and haplo-HSCT with post-transplant Cytoxan (PTCy) and FK506 as GvHD prophylaxis. Chimerism at tolerance studies was donor dominant (97-100%, mean: 99% for both CD33+ myeloid cells and CD3+T cells). Immunosuppression drug (ISD) was withdrawn ~6 months before the time of the in vitro tolerance study described below. We described previously Treg depletion from purified T cells with IL2-immunotoxin (Denileukin Diftitox, Seragen Inc™) to test the involvement of these cells in long-term tolerance. The contribution of Tr1 or anergy was examined by either blocking IL10R or adding low dose IL2, respectively. T-cell exhaustion was tested by blocking the PD1 pathway with anti-PD1 MoAb (OPDIVO, Bristol Myers Squibb™). Purified T cell responses to recipient dendritic cells (DC) were measured in mixed lymphocyte reaction (MLR) assay, and further tested by quantifying cytokine secretion in MLR culture supernatants using Bio-Plex immunoassays (Bio-Rad Lab™). To test for clonal deletion, alloreactive T-cell clones with frequency >0.1% identified in vitro from the graft pre-infusion were tracked by monitoring their T-cell receptor CDR3 sequence serially, in an ImmunoSEQ™ assay (Adaptive Biotech™). Gene expression profiling and signaling pathway analysis on alloreactive or tolerant T-cells were performed by collecting T cells from in vitro MLR reactions, purifying total RNAs from these cells, running RNA-sequencing and analyzing with software of CLC Genomic Workbench®v21, GSEA®v4.1.0 and IPA®. Results: We have previously shown that circulating T cells were hyporeactive to recipient DC in patients at 1yr (or 2yrs in 1 patient) post-haplo-HSCT [6 months, (or 2-5 months in 3 patients) post-ISD withdrawal], while these T cells responded vigorously to 3rd party APC, As positive control, host DC triggered robust 3rd party T-cell response. Neither depletion of Tregs, nor blockade of IL10R or PD1 could reverse T-cell hypo-reactivity. Low-dose IL2 triggered mild anti-host proliferation responses. Similar scenarios were detected in graft T cells against self-DC, (negative control in autologous set up), while vigorous responses were shown in the graft T cells against host-DC pre-haplo-HSCT. Cytokine profiling further confirmed the MLR responses. ImmunoSEQ™ revealed disappearance of alloreactive T-cell clones from peripheral blood with time. Low dose IL2 had minimal impact to reverse hyporeactivity. While most alloreactive T clones were undetectable, a few remained in the peripheral pool in tolerant patients tested (Nee, T et al, Transplantation and Cellular Therapy, 2022;28(3):S44-S45). Unlike graft T-cell responses against host DC, tolerant T-cells in circulation (including remaining alloreactive T cells) against hDC showed distinct patterns of gene expressions, with relative downregulation of allograft rejection (GSEA-Hallmark) (Fig 1A, B, C) and T-helper response, co-stimulation, cell proliferation pathway, that was paired with upregulation of co-inhibition, PD1-PDL1, Ferroptosis, PTEN and CREB pathways (Fig1D). The profiles suggested systemic alterations in the signaling pathways on tolerant T cells post-haplo-HSCT. Conclusion: Hypo-reactivity of donor-derived circulating T cells to recipient DC and graft T cells to graft DC (negative control) were evident. We found Treg, Tr1 activity or T-cell exhaustion to be insignificant as their blockade or removal did not lead to 'flare’ in circulating tolerant T-cell reactivity against patient DC. T-cell clonal deletion appears to be the dominant mechanism explaining the in vitro hyporeactive proliferation, cytokine secretion, and alloreactive TCR clonotype attrition, along with systemically altered signaling pathways in tolerant T-cells including the alloreactive T cells remained. Anergy may play a minor supportive role. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Efficacy and Safety of E7777 (improved purity Denileukin diftitox [ONTAK]) in Patients with Relapsed or Refractory Cutaneous T-Cell Lymphoma: Results from Pivotal Study 302

Introduction: Denileukin diftitox (Dd) is a recombinant fusion protein of diphtheria toxin and human interleukin-2. Dd was approved and marketed as ONTAK in the US from 1999-2014 for treatment of pts with relapsed/refractory CTCL. ONTAK was voluntarily taken off the market in 2014 due to manufacturing difficulties. E7777 was developed as a result of a refined manufacturing process and has an increased percentage of protein monomer species, with a concomitant decrease in levels of misfolded protein and protein aggregates. E7777 has ~1.5-2 times greater specific bioactivity in non-clinical assays compared with ONTAK and is considered a new drug by the FDA. Methods: Objectives: Study 302 (NCT01871727) is a multicenter, open-label, single-arm registrational trial designed to assess efficacy and safety of E7777 in patients with relapsed/refractory CTCL. E7777 was given IV at 9 mcg/kg/day (established from Lead-in) over 60 min for 5 days every 21 days up to 8 cycles. Key inclusion/exclusion criteria included histopathologic diagnosis of CTCL (MF or SS); ECOG performance status 0 or 1; no prior exposure to ONTAK. The primary efficacy endpoint was objective response rate (ORR; CR+PR) per Independent Review Committee (IRC) assessment based on Global Response Score GRS (Olsen, et al., 2011). Secondary efficacy endpoints included duration of response (DOR), time-to-response (TTR), skin response (according to modified Severity Weighted Assessment Tool [mSWAT]), safety and tolerability of E7777, PK, and immunogenicity. Exploratory objectives included progression free survival (PFS), time to progression (TTP), pruritus improvement, and quality of life assessment. Results: A total of 112 patients with CTCL stage I-IV were enrolled in the study: 21 in the Lead-in and 91 in the Main Study. The primary efficacy population is comprised of 69 patients with stage I-III CTCL treated at 9 mcg/kg/day. Median number of prior anticancer therapies in Study 302 were 4.0 (range: 1 to 18). Forty-five patients (65.2%) received ≥4 prior anticancer therapies. Approximately half (34 of 69; 49.3%) of patients had prior exposure to 1 or more FDA-approved targeted therapeutics: romidepsin, brentuximab, or mogamulizumab. Demographic and baseline characteristics of patients included a median age of 64 (range 28-87); ECOG status 0 (56.5%) and 1 (43.5%); Race: 72.5% White, 18.8% Black; 9% Other. There disease stages were 43.5% IA/IB/IIA; 34.8% IIB; and 21.7% IIIA/IIIB. The median (range) number of cycles of E7777 received was 6.0 (1, 42). The primary efficacy endpoint, ORR (95% CI) by IRC, was 36.2% (95% CI: 25.0%, 48.7%), with 8.7% achieving a CR. ORR (95% CI) by Investigator was 42.3% (30.6%, 54.6%), with 8.5% achieving a CR (Table 1). DOR was at least 6 months for 13 (52.0%) responders and at least 12 months for 5 (20.0%) responders. TTR was rapid (median=1.41 months); the majority of responders (~70%) had a response after 1 to 2 cycles of treatment. Treatment with E7777 did not demonstrate any new or unexpected safety findings as compared to prior ONTAK experience. Most patients (98.6%) experienced at least 1 TEAE. Most common TEAEs were nausea (43.5%); fatigue (31.9%); and increased ALT, chills, and peripheral edema (27.5% each). Mean numbers of TEAEs per subject were higher in the first 1 to 2 treatment cycles, then decreased and remained low/stable over the remainder of therapy. Key adverse events of special interest (AESIs) associated with ONTAK in the past (i.e. capillary leak syndrome, hepatotoxicity, infusion reaction, and visual impairment) were primarily Grade 1/2 in our current study and will be discussed in detail in a separate abstract. Conclusions: In study 302, E7777 at a dose of 9 mcg/kg/day demonstrated clinical efficacy and clinically meaningful benefit in heavily pre-treated patients with relapsed/refractory CTCL. The ORR of 36.2% per IRC (42.3% by investigator assessment) showed that a substantial proportion of these heavily pretreated patients experienced clinical benefit after E7777 treatment similar to ONTAK. The observed tumor responses were rapid, durable, and deep. A BLA submission to the FDA is planned for the 2nd half of 2022. E7777 will provide a novel, efficacious, safe, and non-cross-resistant therapeutic option for CTCL patients who have failed other treatments and thus fulfill a serious unmet need. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Safety and Tolerability of E7777 (improved purity Denileukin diftitox [ONTAK]) in Patients with Relapsed or Refractory Cutaneous T-Cell Lymphoma: Results from Pivotal Study 302

Introduction: Denileukin diftitox (Dd), a recombinant fusion protein composed of diphtheria toxin fragments and human interleukin-2 was approved and marketed (as ONTAK) in the US from 1999-2014 for the treatment of relapsed/refractory CTCL. Manufacturing improvements (to decrease the presence of misfolded and aggregated proteins) resulted in a new, more bioactive formulation, E7777. It is considered a new drug by the FDA and required a new registrational clinical trial. Study 302 (NCT01871727) is a multicenter, open-label, single-arm registrational trial in which the primary efficacy and safety of E7777 were assessed. Here, we report the safety results of E7777. Methods: E7777 was given at 9 mcg/kg/day for 5 days every 21 days up to 8 cycles in patients with relapsed/refractory CTCL. Key inclusion/exclusion criteria: histopathologic diagnosis of CTCL; ECOG PS 0 or 1; no prior exposure to ONTAK. Evaluation of safety included incidence and severity of treatment-emergent AEs (TEAEs), and adverse events of special interest (AESIs). Key AESIs include capillary leak syndrome (CLS), infusion reaction, visual impairment (these three AEs were listed as Box warnings in the ONTAK label); and hepatotoxicity. Results: The Primary Efficacy endpoint, ORR (95% CI) by IRC, was 36.2% (95% CI: 25.0%, 48.7%), with 8.7% achieving a CR; detailed efficacy data will be presented in a separate abstract. In the subset of patients with Stage I-III disease (n=69), the median age was 64 years and the median number of E7777 cycles received was 6 (range 1 to 42); 66 patients had mycosis fungoides and 3 had Sezary syndrome, and 39 (57%) had disease of stage IIb or worse. The most common TEAEs were nausea (43.5%); fatigue (31.9%); and increased ALT, chills, and peripheral edema (27.5% each). Thirty patients (43.5%) had a Grade ≥3 TEAE (90% Grade 3; 10% Grade 4)). The most common serious adverse events (≥ 5%) were capillary leak syndrome (10%) and infusion reactions (9%). Overall, the mean numbers of TEAEs per subject were higher in the first 1 to 2 treatment cycles. Most patients [92.8%] had at least 1 AESI (mostly Grade 1/2). Overall, 22 patients (31.9%) experienced AESIs that were Grade ≥3; (7.2%) had drug discontinuation; (4.3%) had drug dose reduction, and (26.1%) had drug dose interruption. Fourteen patients (20.3%) had CLS. CLS was defined as the occurrence of at least 2 of the following: hypotension, edema, or serum albumin < 3.0 g/dL. CLS was Grade 1 in 2.9%, Grade 2 in 11.6%, Grade 3 in 4.3%, and Grade 4 in 1.4%. Nine patients (13.0%) underwent drug modification: (4.3%) discontinued E7777; and (10.1%) had either dose reduction or temporary dose interruption. CLS typically occurred in the first 1/2 cycles. Risk/severity of CLS was mitigated by fluid management; confirmation of serum albumin levels (≥ 3.0 g/dl); close monitoring of weight, edema, and BP; early drug interruption; and rapid initiation of diuretic therapy on recovery. Fifty-one patients (73.9%) had an AESI related to infusion reaction. Grade 1 in 43.5%, Grade 2 in 26.1%, and Grade 3 in 4.3%. One patient (1.4%) had study drug discontinuation, and (11.6%) had either study drug dose reduction or interruption. In the event of infusion-related reactions, systemic corticosteroids may be added to premedication for subsequent E7777 infusions. Nine patients (13.0%) had an event related to visual impairment; all were AEs of blurred vision, which was Grade 1 in 11.6% and Grade 2 in 1.4%; no Grades 3, 4, or 5. One patient (1.0%) had drug interruption; no events led to study drug dose reduction. Twenty-five patients (36.2%) had AESI related to hepatoxicity. The TEAEs were Grade 1 in 17.4%, Grade 2 in 7.2%, Grade 3 in 11.6%, and no Grade 4/5. The majority of hepatic adverse events were elevations in transaminases that occurred within the first or second cycle, resolved without medical intervention, and did not require treatment discontinuation. Conclusion: No new safety signals were observed with E7777 when compared to the safety profile of ONTAK. There is no evidence of cumulative toxicity. Most patients had at least 1 TEAE which were mostly Grade 1/2. Specific AESIs: CLS, infusion reactions, and visual impairment (prior ONTAK Box warnings) were mostly Grade 1/2 and effectively managed. Overall, E7777 was well-tolerated with the use of pre-medications, close patient monitoring, and prompt initiation of supportive measures and drug management. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Preclinical and clinical researches of Denileukin Diftitox (Genetical Recombination) (Remitoro®), a novel agent for T-cell lymphoma

Denileukin Diftitox (DD) is a recombinant fusion protein of diphtheria toxin (DT) fragments and human interleukin-2 (IL-2). DD binds to IL-2 receptor (IL-2R) expressed on tumor cells and is taken up into the cells. Subsequently, DT fragments with adenosine diphosphate ribosylation enzyme inhibit protein synthesis, then ultimately trigger cell death. DD binds to both high- and intermediate-affinity IL-2Rs via IL-2 domain and inhibits growth of human T-cell lymphomas cell lines. E7777, which contains DD as an active component, has improved purity and an increased percentage of active monomer compared with the approved drug E7272 (ONTAK in the US, not approved in Japan). In the phase I clinical study in Japanese patients with relapsed or refractory peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL), the maximum tolerated dose and recommended dose of E7777 were 9 μg/kg/day (administered on Days 1-5 of each cycle) based on the evaluation of dose-limiting toxicity. In the phase II clinical study, the objective response rate was 36.1%, showing comparable efficacy to existing therapies. E7777 showed anti-tumor activity observed across the range of CD25 expression. Grade 3 or higher adverse events (AE) occurred in 94.6%, and serious AE such as capillary leak syndrome and rhabdomyolysis were reported. Therefore, safety monitoring activities have been continued along with alerting related events. Based on these results, E7777 obtained a new drug approval in Japan in March 2021 for the indication of relapsed or refractory PTCL/CTCL.

Immunotherapy in indolent Non-Hodgkin's Lymphoma

Treatment of non-Hodgkin lymphoma (NHL) in general has improved over the years with the emergence of the monoclonal antibodies (MAB) therapy. NHL is divided into B cell NHL and T cell NHL. Treatment of NHL was based on the subtype of NHL and its staging. NHL is divided into aggressive and indolent NHL (iNHL). Subtypes of iNHL include: Follicular lymphoma (FL), Marginal zone lymphoma (MZL), Chronic lymphocytic leukemia/small-cell lymphocytic lymphoma (CLL/SLL), Gastric mucosa-associated lymphoid tissue (MALT) lymphoma, Lymphoplasmacytic lymphoma, Waldenström macroglobulinemia, Nodal marginal zone lymphoma (NMZL), Splenic marginal zone lymphoma (SMZL). Chemotherapy was the main stay treatment of iNHL until the emergence of Rituximab, anti-CD20 MAB targeting CD-20 surface cell antigens that are present on B-cells lymphoma and not on precursor cells, mainly efficacious in B cell iNHL, It became the mainstay treatment in follicular lymphoma (FL) as a single agent modality or in combination with chemotherapy. The anti-CD20 Rituximab played an important role in the development of the treatment of iNHL to become FDA approved in 1997. It was also proven effective in multiple other types of lymphoma. MAB through targeting the cell surface antigen leads to a direct or immune mediated cytotoxicity. This carries few side effects, including allergic reactions. Other than that, a resistance mechanism to rituximab emerged by inducing a failure in the apoptosis mechanism. Alternative mechanisms of resistance included the presence of soluble antigens that could act by binding to the antibody present before the drug itself can bind the lymphoma cell. Thus, the interest in immunotherapy grew further to explore the possibility of conjugating an immune mediated drug to a radio-sensitizing agent in order to enhance the selectivity of the drug. Here came the development of 90Y-ibritumomab tiuxetan and 131I-tositumomab. After it, humanized anti-CD20 emerged ofatumumab, IMMU106 (veltuzumab) in 2005, and ocrelizumab which are considered as second generation anti-CD20 and 3rd generation anti-CD20 include AME-133v (ocaratuzumab), PRO131921 and GA101 (obinutuzumab). Also multiple other agents emerged targeting different surface cell antigens like CD52 (alemtuzumab), CD22 (unconjugated epratuzumab and calicheamicin conjugated CMC-544 [inotuzumab ozogamicin]), CD80 (galiximab), CD2 (MEDI-507 [siplizumab]), CD30 (SGN-30 and MDX-060 [iratumumab], Brentuximab vedotin), CD40 (SGN-40), and CD79b (Polatuzumab). Other agents include MAB targeting T-Cells like mogamulizumab, Denileukin Diftitox and BiTEs or bispecific T cell engagers like Mosunetuzumab, Glofitamab, and Epcoritamab. Moreover, further studies came up to evaluate the role of immunotherapy in combination chemotherapy as a pathway to evade the resistance mechanisms. Side effects of the treatment were mainly infusion related adverse reactions, myelosuppression in conjugated forms leading to immunosuppression and subsequently to infectious complications. Another important aspect in immunotherapy is the half-lives of the medication which is an important factor that can influence the evaluation of the response. The MAB treatment showed important benefit in the treatment of iNHL and it continuously shows how rapidly it can develop to provide optimum care and benefit to patients with iNHL.

Current treatment strategies and emerging therapies for cutaneous lymphoma.

Cutaneous lymphoma is generally treated with skin-directed therapies (SDT) during the early and localized stages. For the refractory or advanced stages, systemic therapies are used. Previously, retinoids and interferons were used for SDT-resistant cases. Only a few chemotherapy options were available for more advanced disease. In recent years, many novel agents have been introduced and the strategy for systemic therapy has changed, especially for cutaneous T-cell lymphoma (CTCL). For SDT, helical tomotherapy, a new radiation modality, has been drawing attention as an option for radiotherapy. Targeted therapies such as histone deacetylase inhibitors, mogamulizumab, brentuximab vedotin, and denileukin diftitox are new treatment options. Chemotherapy agents such as gemcitabine and pralatrexate have been introduced; they are expected to have meaningful efficacy as monotherapy. Allogeneic hematopoietic stem cell transplantation is still considered for young patients with advanced CTCL as the only potentially curative treatment.

Pseudomonas Exotoxin-Based Immunotoxins: Over Three Decades of Efforts on Targeting Cancer Cells With the Toxin.

Cancer is one of the prominent causes of death worldwide. Despite the existence of various modalities for cancer treatment, many types of cancer remain uncured or develop resistance to therapeutic strategies. Furthermore, almost all chemotherapeutics cause a range of side effects because they affect normal cells in addition to malignant cells. Therefore, the development of novel therapeutic agents that are targeted specifically toward cancer cells is indispensable. Immunotoxins (ITs) are a class of tumor cell-targeted fusion proteins consisting of both a targeting moiety and a toxic moiety. The targeting moiety is usually an antibody/antibody fragment or a ligand of the immune system that can bind an antigen or receptor that is only expressed or overexpressed by cancer cells but not normal cells. The toxic moiety is usually a protein toxin (or derivative) of animal, plant, insect, or bacterial origin. To date, three ITs have gained Food and Drug Administration (FDA) approval for human use, including denileukin diftitox (FDA approval: 1999), tagraxofusp (FDA approval: 2018), and moxetumomab pasudotox (FDA approval: 2018). All of these ITs take advantage of bacterial protein toxins. The toxic moiety of the first two ITs is a truncated form of diphtheria toxin, and the third is a derivative of Pseudomonas exotoxin (PE). There is a growing list of ITs using PE, or its derivatives, being evaluated preclinically or clinically. Here, we will review these ITs to highlight the advances in PE-based anticancer strategies, as well as review the targeting moieties that are used to reduce the non-specific destruction of non-cancerous cells. Although we tried to be as comprehensive as possible, we have limited our review to those ITs that have proceeded to clinical trials and are still under active clinical evaluation.

Meta-Analysis of Interleukin-2 Receptor Antagonists as the Treatment for Steroid-Refractory Acute Graft-Versus-Host Disease.

Acute graft-versus-host disease (aGVHD) is a major complication after allogeneic hematopoietic stem cell transplantation (HSCT). Corticosteroid is the first-line treatment for aGVHD, but its response rate is only approximately 50%. At present, no uniformly accepted treatment for steroid-refractory aGVHD (SR-aGVHD) is available. Blocking interleukin-2 receptors (IL-2Rs) on donor T cells using pharmaceutical antagonists alleviates SR-aGVHD. This meta-analysis aimed to compare the efficacy and safety of four commercially available IL-2R antagonists (IL-2RAs) in SR-aGVHD treatment. A total of 31 studies met the following inclusion criteria (1): patients of any race, any sex, and all ages (2); those diagnosed with SR-aGVHD after HSCT; and (3) those using IL-2RA-based therapy as the treatment for SR-aGVHD. The overall response rate (ORR) at any time after treatment with basiliximab and daclizumab was 0.81 [95% confidence interval (CI): 0.74–0.87)] and 0.71 (95% CI: 0.56–0.82), respectively, which was better than that of inolimomab 0.54 (95% CI: 0.39–0.68) and denileukin diftitox 0.56 (95% CI: 0.35–0.76). The complete response rate (CRR) at any time after treatment with basiliximab and daclizumab was 0.55 (95% CI: 0.42–0.68) and 0.42 (95%CI: 0.29–0.56), respectively, which was better than that of inolimomab 0.30 (95% CI: 0.16–0.51) and denileukin diftitox 0.37 (95% CI: 0.24–0.52). The ORR and CRR were better after 1-month treatment with basiliximab and daclizumab than after treatment with inolimomab and denileukin diftitox. The incidence of the infection was higher after inolimomab treatment than after treatment with the other IL-2RAs. In conclusion, the efficacy and safety of different IL-2RAs varied. The response rate of basiliximab was the highest, followed by that of daclizumab. Prospective, randomized controlled trials are needed to compare the efficacy and safety of different IL-2RAs.

The co-expression of denileukin diftitox immunotoxin with Artemin: soluble and aggregation analysis in presence of an efficient protein chaperone

The co-expression of denileukin diftitox immunotoxin with Artemin: soluble and aggregation analysis in presence of an efficient protein chaperone

Is Durability of Response Reported in Refractory CTCL: A Systematic Review

Introduction: Primary cutaneous T-cell lymphomas (CTCL) are a group of non-Hodgkin lymphomas derived from T-lymphocytes that infiltrate the skin. In refractory CTCL, treatments generally include systemic therapies in conjunction with skin-directed therapies. Numerous assessment criteria are used to evaluate the efficacy of different therapies administered to patients with CTCL. Robust treatment comparisons in CTCL are currently complicated by differences between studies in the efficacy outcomes reported. A systematic review (SR) was performed to summarise published evidence on the efficacy of treatments in patients with relapsed/refractory CTCL.Methods: A SR was performed in January 2017 to identify clinical studies published in the last 10 years enrolling >20 patients treated for refractory CTCL.Results: In total, 63 publications reporting on 54 unique studies and 21 different therapies for refractory CTCL were included in the SR. The majority of included studies (n=49) were single arm investigations. Five of the studies included were randomised controlled trials (RCT) comparing CTCL therapies. Two RCTs compared multiple doses of a single therapy (bexarotene or denileukin diftitox), two compared multiple therapies (interferon and methotrexate vs interferon and retinoids or brentuximab vs methotrexate or bexarotene), and one was a placebo-controlled trial of denileukin diftitox. Patient cohorts ranged in size from 21 to 216 patients and all patients had recurrent or refractory disease following ≥1 therapy for CTCL prior to the therapy for which data were extracted. The most frequently reported outcomes were objective response rate (ORR) reported in 82% of studies, complete response rate (80%), progression-free survival (52%), duration of response (48%), overall survival (24%) and time to tumour progression (20%) (Table 1). However, not all outcomes were reported for all therapies, outcome assessment criteria were not reported in all studies, and durable responses were rarely reported. In addition, there was substantial heterogeneity between studies in terms of patient characteristics, outcome assessment criteria, study design, and follow-up time. As such, a robust comparison of relative efficacy is not feasible. ORR was the most consistently reported outcome across studies and was reported for 19 different therapies in 44 different studies. The assessment criteria for ORR was reported in 15 studies. ORR is a useful measure of efficacy as it is directly attributable to drug effect and can be assessed in single-arm studies; however, as the time-point for assessment of ORR or the definition of ORR differed between studies or was not reported, the durability of response was difficult to interpret. The novel outcomes, objective global responses lasting at least 4 (ORR4) and 6 months (ORR6), were reported in three and two trials investigating the efficacy of brentuximab vedotin, respectively. ORR4 and ORR6 capture both the proportion of patients achieving a response and response duration as a single measurement and were 51-56% and 34%, respectively, following treatment with brentuximab vedotin. Health-related quality of life was investigated in only one study in which key endpoints, such as Skindex-29 symptom domains, were reported. Adverse events were reported following treatment with all therapies for refractory CTCL. However, there was a lack of consistency in the definition of the severity of adverse events reported.Conclusion: Although progress has been made towards the standardisation of response criteria in CTCL, the evaluation of durability of response to treatment remains inconsistent. The routine use of clearly defined efficacy outcomes in clinical trials is required to enable robust comparisons of therapeutic efficacy. [Display omitted] DisclosuresDalal:Takeda Pharmaceuticals International Co: Employment, Equity Ownership. Mitchell:DRG Abacus: Employment. McCloskey:DRG Abacus: Employment. Zagadailov:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Gautam:Takeda Pharmaceuticals International Co: Employment, Equity Ownership.

Phase II study of E7777 in Japanese patients with relapsed/refractory peripheral and cutaneous T‐cell lymphoma

E7777 is a recombinant cytotoxic fusion protein composed of the diphtheria toxin fragments A and B and human interleukin‐2. It shares an amino acid sequence with denileukin diftitox, but has improved purity and an increased percentage of active monomer. We undertook a multicenter, single‐arm phase II study of E7777 in patients with relapsed or refractory peripheral T‐cell lymphoma (PTCL) and cutaneous T‐cell lymphoma (CTCL) to evaluate its efficacy, safety, pharmacokinetics, and immunogenicity. A total of 37 patients were enrolled, of which 17 and 19 patients had PTCL and CTCL, respectively, and one patient with another type of lymphoma (extranodal natural killer/T‐cell lymphoma, nasal type), diagnosed by the Central Pathological Diagnosis Committee. Among the 36 patients with PTCL and CTCL, objective response rate based on the independent review was 36% (41% and 31%, respectively). The median progression‐free survival was 3.1 months (2.1 months in PTCL and 4.2 months in CTCL). The common adverse events (AEs) observed were increased aspartate aminotransferase (AST) / alanine aminotransferase (ALT), hypoalbuminemia, lymphopenia, and pyrexia. Our results indicated that a 9 µg/kg/d dose of E7777 shows efficacy and a manageable safety profile in Japanese patients with relapsed or refractory PTCL and CTCL, with clinical activity observed across the range of CD25 expression. The common AEs were manageable, but increase in ALT / AST, hypoalbuminemia, and capillary leak syndrome should be carefully managed during the treatment.

IFNα Augments Clinical Efficacy of Regulatory T-cell Depletion with Denileukin Diftitox in Ovarian Cancer

AbstractPurpose:Immunotherapy treats some cancers, but not ovarian cancer. Regulatory T cells (Tregs) impede anti-ovarian cancer immunity but effective human Treg-directed treatments are lacking. We tested Treg depletion with denileukin diftitox (DD) ± IFNα as ovarian cancer immunotherapy.Patients and Methods:Mice with syngeneic ID8 ovarian cancer challenge were treated with DD, IFNα, or both. The phase 0/I trial tested one dose-escalated DD infusion for functional Treg reduction, safety, and tolerability. The phase II trial added IFNα2a to DD if DD alone failed clinically.Results:DD depleted Tregs, and improved antitumor immunity and survival in mice. IFNα significantly improved antitumor immunity and survival with DD. IFNα did not alter Treg numbers or function but boosted tumor-specific immunity and reduced tumor Treg function with DD by inducing dendritic cell IL6. DD alone was well tolerated, depleted functional blood Tregs and improved immunity in patients with various malignancies in phase 0/I. A patient with ovarian cancer in phase 0/I experienced partial clinical response prompting a phase II ovarian cancer trial, but DD alone failed phase II. Another phase II trial added pegylated IFNα2a to failed DD, producing immunologic and clinical benefit in two of two patients before a DD shortage halt. DD alone was well tolerated. Adding IFNα increased toxicities but was tolerable, and reduced human Treg numbers in blood, and function through dendritic cell–induced IL6 in vitro.Conclusions:Treg depletion is clinically useful but unlikely alone to cure ovarian cancer. Rational treatment agent combinations can salvage clinical failure of Treg depletion alone, even when neither single agent provides meaningful clinical benefit.

Phase I Study of Yttrium-90 Labeled ANTI-CD25 (aTac) Monoclonal Antibody PLUS BEAM for Autologous Hematopoietic Cell Transplantation (AHCT) in Patients with Mature T-Cell NON-Hodgkin Lymphoma, the “a-TAC-BEAM Regimen”

Background: Peripheral T cell lymphomas (PTCL) have a poor prognosis with current treatment regimens. High-dose chemotherapy followed by autologous stem cell transplant (ASCT) has been used as a consolidation strategy in remission states (CR1 or above) endorsed by the NCCN guidelines in appropriate patients. 5-year DFS is reported at 70% for alk -ve anaplastic large cell lymphoma (ALCL) and 30-40% for most other histologies (D'Amore et al, 2012, JCO). It is also performed in the relapsed settings if no previous ASCT performed and allogeneic transplant is not an option. CD25 is a targetable protein expressed differentially in PTCL and antibody based anti-CD25 therapies are efficacious in PTCL i.e denileukin diftitox (Foss et al Blood 2006, Dang et al, BJH 2006) , monoclonal antibody dacluzimab (Waldman et al 1995 Blood). Yttrium-90 (90Y) labeled chimeric antiCD25 antibody basiliximab emits beta particles and has been shown to inhibit the growth of human ALCL tumors and increase survival in SUDHL-1 xenograft mice (Zhang et al 2009 Cancer Biother Radiopharm). Previous investigations at COH by Raubitschek, Colcher et al established a safe does of Yttrium-90 (90Y) labeled basiliximab at 0.4mCi/kg in combination with BEAM. This is a phase 1 clinical trial of a novel conditioning regimen that includes the use of Yttrium-90 (90Y) labeled basiliximab with BEAM chemotherapy for PTCL patients eligible for ASCT. The trial utilizes a modified version of the rolling 6 design (Skolnik et al) to test 3 dose levels of Yttrium-90 (90Y) Basiliximab i.e 0.4mCi/kg, 0.5miC/kg and 0.6mCi/kg with the primary objective of evaluating the safety and tolerability of this combination and to establish the MTD. Secondary objectives include estimating incidence of relapse, OS, PFS, NRM at day 100, 1 year and 2 years post-transplant. Patients and Methods: Dose limiting toxicity (DLT) is defined according to the Bearman and CTCAE 4.03 scales, the latter for hematologic toxicity. The study/treatment schema is shown in Figure 1. Results: From 07/29/2015 to 06/10/2020, 20 patients underwent ASCT on this trial; n=4 at 0.4mCi/kg n=4 at 0.5mCi/kg and n=12 at 0.6mCi/kg. Median age at ASCT was 51 years (range: 18-76), and histologies included; PTCL-nos (n=10); alk-ve ALCL (n=5); angioimmunoblastic T-cell lymphoma (n=3); and intestinal T-cell lymphoma (n=2). Disease status at ASCT were CR1 in18, CR2 in 2 patients. Median number of prior therapies was 1 (range: 1-4). At a median follow-up of 17.1 months (range: 0.9-26.2), 12 patients remain in remission, 8 have relapsed out of which 5 have died of progressive lymphoma. OS was 100% (95% CI: N/A) at 100-days, and 83% (95% CI: 57-94) at 1 year. Non-relapse Mortality was 0% at both 100-days and 1-year. All patients successfully engrafted with the median days to ANC &amp;gt;= 500/ul was 10 (range: 10 - 21), and days to PLT &amp;gt;= 20,000/ul: 13 (12 - 92). Overall, no dose limiting toxicities were experienced. The most common/highest grade toxicity experienced (per Bearman Scale) was grade 2 stomatitis, which was seen in 3 patients at 0.4mCi/kg; 4 patients at 0.5 mCi/kg, and 7 at0.6mCi/kg. The only other toxicities seen were grade 2 GI in 2 patients at 0.4mCi/kg, and grade 2 bladder in one patient at 0.6mCi/kg dose.. Toxicities &amp;gt;grade 2 were not seen. Conclusion: aTac- BEAM appears to be safe as an ASCT conditioning regimen for PTCL with no increased toxicity as compared to the historical toxicities seen with BEAM alone in this patient population (D'Amore 2012 J of Clin Onc). The dose level 0.6mCi/kg will likely be the recommended phase II dose. An expanded phase is planned to evaluate the efficacy of this regimen followed by a randomized trial of BEAM alone plus a combination of aTac- BEAM. Figure 1 Disclosures Zain: Mundi Pharma: Research Funding; Seattle Genetics: Research Funding; Kyowa Kirin: Research Funding. Herrera:Gilead Sciences: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Immune Design: Research Funding; AstraZeneca: Research Funding; Karyopharm: Consultancy; Pharmacyclics: Research Funding; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Other: Travel, Accomodations, Expenses, Research Funding; Merck: Consultancy, Research Funding. Salhotra:Kadmon: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding. Nakamura:NapaJen Pharma: Consultancy; Celgene: Other: Support on seminar; Magenta Therapeutics: Other: Advisory board meeting; Viracor: Consultancy; Merck: Other: advisory board meeting; Alexion: Other: Support on a meeting presentation; Kyowa-Kirin: Other: Support on a meeting presentation; Kadmon Corporation: Other: Advisory board meeting. OffLabel Disclosure: Yittrium labelled Basiliximab

Interventions for mycosis fungoides.

Interventions for mycosis fungoides.