Checkpoint inhibition in hematologic malignancies

Checkpoint inhibitor therapy has emerged as an effective therapeutic strategy for many types of malignancies, especially in solid tumors. Within the last two decades, numerous monoclonal antibody drugs targeting the CTLA-4 and PD-1/PD-L1 checkpoint pathways have seen FDA approval. Within hematologic malignancies, Hodgkin Lymphoma has seen the greatest clinical benefits thus far with more recent data showing efficacy in the front-line setting. As our understanding of checkpoint inhibition expands, using these pathways as a therapeutic target has shown some utility in the treatment of other hematologic malignancies as well, primarily in the relapsed/refractory settings. Checkpoint inhibition also appears to have a role as a synergistic agent to augment clinical responses to other forms of therapy such as hematopoietic stem cell transplant. Moreover, alternative checkpoint molecules that bypass the well-studied CTLA-4 and PD-1/PD-L1 pathways have emerged as exciting new therapeutic targets. Most excitingly is the use of anti-CD47 blockade in the treatment of high risk MDS and TP-53 mutated AML. Overall, there has been tremendous progress in understanding the benefits of checkpoint inhibition in hematologic malignancies, but further studies are needed in all areas to best utilize these agents. This is a review of the most recent developments and progress in Immune Checkpoint Inhibition in Hematologic Malignancies in the last decade.

A Novel bispecific T-cell engager (BiTE) targeting CD22 and CD3 has both in vitro and in vivo activity and synergizes with blinatumomab in an acute lymphoblastic leukemia (ALL) tumor model

Immunotherapy has revolutionized cancer therapy. Two recently FDA-approved immunotherapies for B-cell malignancies target CD19, in the form of a Bispecific T-Cell Engager (BiTE) antibody construct or chimeric antigen receptor T (CAR-T) cells. Blinatumomab, an FDA-approved BiTE, binds to CD19 on B cells and to CD3 on T cells, mediating effector-target cell contact and T-cell activation that results in effective elimination of target B cells. Although CD19 is expressed by essentially all B-cell malignancies at clinical presentation, relapses with loss or reduction in CD19 surface expression are increasingly recognized as a cause of treatment failure. Therefore, there is a clear need to develop therapeutics for alternate targets. We have developed a novel BiTE consisting of humanized anti-CD22 and anti-CD3 single chain variable fragments. Target binding of the anti-CD22 and anti-CD3 moieties was confirmed by flow cytometry. CD22-BiTE promoted in vitro cell-mediated cytotoxicity in a dose and effector: target (E:T)-dependent fashion. Additionally, in an established acute lymphoblastic leukemia (ALL) xenograft mouse model, CD22-BiTE demonstrated tumor growth inhibition, comparable to blinatumomab. Further, the combination of blinatumomab and CD22-BiTE yielded increased efficacy in vivo when compared to the single agents. In conclusion, we report here the development of a new BiTE with cytotoxic activity against CD22+ cells which could represent an alternate or complementary therapeutic option for B-cell malignancies.

A Fermented Wheat Germ Extract Contains Protein Components Active against NSCLC Xenografts In Vivo

Non-small cell lung cancer (NSCLC) continues to be the leading cause of cancer-related deaths. Although advances have been made in the past decade to treat such tumors, most options induce multiple side effects, and many patients discontinue therapy due to toxicity. Thus, the need remains for non-toxic, effective NSCLC therapies, especially in an elderly patient population. Our lab has previously identified a protein fraction from the nutraceutical Avemar®-dubbed fermented wheat germ protein (FWGP)-with demonstrated efficacy in lymphoma models both in vitro and in vivo. Here, we show that FWGP also has anti-tumor activity in vitro and in vivo against lung cancer. In vitro cytotoxicity against multiple lung cancer cell lines yielded IC50 values comparable to those previously established with the parent product, Avemar. Further, significant A549 xenograft growth inhibition occurred in athymic nu/nu mice receiving FWGP in both pre-radiated and non-radiated models when compared to the untreated control. Encouragingly, mice treated with FWGP experienced no toxicities as detected by weight reduction or blood chemistry analysis. These data support the further study of FWGP as a potential non-toxic therapy for lung cancer and other oncologic indications.

Targeting the Inducible T-cell Costimulator (ICOS) in Patients with Relapsed/Refractory T-follicular Helper Phenotype Peripheral T-cell and Angioimmunoblastic T-cell Lymphoma

PURPOSE

Proliferation of T-follicular helper (TFH) CD4+ T cells is a postulated pathogenic mechanism for T-cell non-Hodgkin lymphomas (T-NHL). The inducible T-cell costimulator (ICOS) is highly expressed by TFH, representing a potential target. MEDI-570 is a monoclonal antibody against ICOS, which eliminates ICOS+ cells in preclinical models.

PATIENTS AND METHODS

We report the safety, pharmacokinetics (PK), pharmacodynamics (PD), and clinical activity of MEDI-570 in T-NHL. NCI-9930 is a phase I, first-in-human study of MEDI-570 in relapsed/refractory malignant T-NHL known to express ICOS. MEDI-570 was administered intravenously every 3 weeks for up to 12 cycles. Primary endpoints were safety, dose-limiting toxicities (DLT), and recommended phase II dose (RP2D). Secondary and exploratory endpoints included efficacy parameters and various correlative studies. This study is supported by the National Cancer Institute (NCT02520791).

RESULTS

Twenty-three patients were enrolled and received MEDI-570 at five dose levels (0.01-3 mg/kg). Sixteen (70%) had angioimmunoblastic T-cell lymphoma (AITL); median age was 67 years (29-86) and the median prior lines of therapies was 3 (1-16). Most common grade 3 or 4 adverse events were decreased CD4+ T cells (57%), lymphopenia (22%), anemia (13%), and infusion-related reactions (9%). No DLTs were observed. The RP2D was determined at 3 mg/kg. Analysis of T-cell subsets showed reductions in CD4+ICOS+ T cells reflecting its effects on TFH cells. The response rate in AITL was 44%.

CONCLUSIONS

MEDI-570 was well tolerated and showed promising clinical activity in refractory AITL. MEDI-570 resulted in sustained reduction of ICOS+ T lymphocytes.

Clinical experience with frontline Hyper-CVAD-based regimens, including Hyper-CVAD plus ponatinib, in patients with acute lymphoblastic leukemia treated at a comprehensive cancer center

BACKGROUND

Hyper-CVAD is an established regimen for adult ALL that was developed at the MD Anderson Cancer Center (MDACC). However, results can vary across different institutions given the heterogeneity of patient populations and institutional practices. Moreover, while a MDACC study demonstrated that the combination of ponatinib plus hyper-CVAD produced remarkable activity in untreated Ph+ ALL, it remains to be externally validated. We sought to validate those findings in previously untreated adult patients with Ph+ ALL.

METHODS

This was a retrospective study analyzing the outcomes of previously untreated adult ALL patients treated with hyper-CVAD, with a focus on Ph+ ALL patients treated with ponatinib plus hyper-CVAD.

RESULTS

82 patients were included. The median age was 51 years. The median follow-up was 2.62 years. The 5-year overall survival (OS) and event-free survival (EFS) were 39.5 % and 28.2 %, respectively. For Ph+ ALL patients (n = 13) receiving ponatinib plus hyper-CVAD, 3-year OS and EFS were both 92.3 %. Univariate analysis showed a high WBC and poor-risk cytogenetics to be associated with inferior outcomes, while CD20 + predicted favorable outcomes in B-ALL patients. On multivariate analysis, CD20 + retained significance for Philadelphia-negative (Ph-) ALL. For Ph+ ALL, ponatinib was associated with better OS and EFS on univariate and multivariate analysis.

CONCLUSION

Our data supports the use of ponatinib plus hyper-CVAD as a standard of care regimen for Ph+ ALL. Our outcomes for Ph-ALL and T-cell ALL (T-ALL) show that advances are still needed in the frontline setting, and clinical trial enrollment is recommended.

Phase 1/2 study of zilovertamab and ibrutinib in mantle cell lymphoma (MCL) or chronic lymphocytic leukemia (CLL)

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Background: Zilovertamab (Zilo) is a humanized monoclonal antibody that inhibits the tumor promoting activity of ROR1 and has demonstrated additive/synergistic activity with many anti-cancer agents, including ibrutinib (Ibr). Methods: Patients (Pts) with relapsed or refractory (RR) MCL or treatment-naïve (TN) or RR CLL were enrolled. In Part 1 (Dose Escalation), multiple doses were examined. Zilo 600 mg IV starting q2wks x3 then q4wks + Ibr qD was selected as the recommended dosing regimen for use in Part 2 (Expansion) and Part 3 (CLL only, Zilo+Ibr vs. Ibr alone). Results: As of 18Jan2022 data cutoff, 26 evaluable RR MCL pts, including pts who received prior Ibr (5) or auto-SCT (7), and 34 evaluable CLL pts (12 TN and 22 RR) were enrolled into Parts 1&2. In Part 3, 22 evaluable pts were randomized (2:1) to receive either Zilo+Ibr (15) or Ibr (7). Safety: Treatment-emergent adverse events (TEAEs) (≥30%, N = 84), regardless of relationship, included fatigue (41.7%), contusion (39.3%), and diarrhea (38.1%). Most common (≥5%) Grade ≥3 TEAEs included hypertension (10.7%), pneumonia (7.1%), atrial fibrillation, fatigue, and neutropenia (all 6.0%). Grade ≥3 neutrophil decrease observed in 9.4% or 17.6%, platelet decrease in 12.5% or 2.9%, or hemoglobin decrease in 9.4% or 0% of pts with MCL or CLL, respectively in Parts 1&2. Investigators scored TEAEs as due to Ibr in 78.1% or 85.3%, or to Zilo in 15.6% or 23.5% of pts with MCL or CLL, respectively. Efficacy (MCL): Objective response rate (ORR) was 80.8% (34.6% CR, 46.2% PR). ORR for pts with prior Ibr was 80% (2CR, 2PR) and median duration of response (mDOR) was 13.7 months (M) (95%CI: 11.93, NE). ORR was 100% in pts who had prior SCT+/- CAR-T (5CR, 2PR), and mDOR was 34.1 M (95% CI 13.84, NE). Overall median PFS (mPFS) was 35.9 M (95% CI: 17.3, NE) at median follow-up of 15.0 M. For MCL pts with TP 53 aberrancy (6), Ki67 > 30% (13), ≥ 3 prior lines of therapies (4), blastoid histology (3), bulky disease ≥5 cm (4), intermediate MIPIb (6), or high MIPIb (11), the mPFS (in M) was 17.3 (95% CI: 2.85, NE), Not Reached (NR) (95% CI: 2.85, NE), 35.9 (95% CI: 16.52, NE), NR (min 9.18, max 27.87), 26.6 (95% CI: 0.03, NE), 35.9 (min 8.30, max 35.9) or 16.5 (95% CI: 2.72, NE). Efficacy (CLL): In Parts 1&2 ORR was 91.2% (8.8% CR, 82.3% PR/PR-L), and 8.8% had stable disease (SD). At median follow-up of 31.4 M, mDOR was 33.5 M and mPFS was NR (95% CI: 36.3, NE); the mPFS (in M) for pts with 1, 2, or ≥ 3 prior therapies was NR (min 19.3, max 41.3), NR (min 31.3, max 36.8) or 36.3 (95% CI: 15.7, NE). At median follow-up of 21.1 M in Part 3, mPFS was NR for TN or RR in both Zilo+Ibr and Ibr arms. Conclusions: Zilo+Ibr is well-tolerated. Striking responses were observed in MCL pts, with mPFS of 35.9 M (95% CI: 17.3, NE) and CR of 34.6%, which compares favorably to mPFS of 12.8 M (95% CI 8.5, 16.6) and CR of 20% reported for single agent Ibr (Rule 2017). For CLL, ORR and PFS compare very favorably to Ibr monotherapy data (Byrd 2019). Clinical trial information: NCT03088878.

Long-term Follow-up and Correlative Analysis of Two Phase II Trials of Rituximab and Lenalidomide Followed by Continuous Lenalidomide in Untreated and Relapsed/Refractory Indolent Lymphoma

PURPOSE

Rituximab and lenalidomide are effective for previously untreated and relapsed/refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). However, long-term survival and predictive biomarkers are not well described.

PATIENTS AND METHODS

We conducted two phase II open-label trials involving 60 patients with previously untreated and R/R advanced-stage iNHL. Patients received lenalidomide and rituximab induction followed by continuous lenalidomide until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Correlative studies included plasma cytokine monitoring, flow cytometry of peripheral blood mononuclear cells (PBMC; days 0, 15, 30, and 60), and RNA sequencing (RNA-seq) of pretreatment tumor biopsies.

RESULTS

At a median follow-up of 63 months for previously untreated and 100 months for R/R, ORR was 82% for both. The 11 R/R patients who achieved complete remission remained in continuous remission for 16 to 141 months, thereafter. Median overall survival (OS) was not reached in the previously untreated and was 140 months (95% confidence interval, 53.4-140) in the R/R group. A mixed-effects linear regression model identified significant associations between Granzyme B⁺ (GranB⁺) CD8⁺ T cells and long-term complete response (LTCR; P = 5.3e-4). Furthermore, prior to start of therapy, treatment response could be predicted by B-cell and GranB⁺ CD8⁺ T-cell levels (% total lymphocytes).

CONCLUSIONS

Rituximab plus lenalidomide followed by continuous lenalidomide is effective with manageable toxicity in patients with previously untreated and R/R iNHL. This regimen produces durable remissions, even in heavily pretreated patients, with some lasting greater than 10 years. GranB⁺ CD8⁺ T cells, B cells, and plasma IFNγ allowed prediction of LTCR but need validation in larger trials.

Phase 1/2 study of cirmtuzumab and ibrutinib in mantle cell lymphoma (MCL) or chronic lymphocytic leukemia (CLL)

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Background: Cirmtuzumab (Cirm) is a humanized monoclonal antibody that inhibits the tumor promoting activity of ROR1 and had demonstrated additive/synergistic activity with many anti-cancer agents including ibrutinib (Ibr). Methods: Patients (Pts) with relapsed or refractory (RR) MCL or treatment naïve (TN) or RR CLL were enrolled. In Part 1 (Dose Escalation), doses of Cirm IV q2wks x5 then q4wks of 2-16 mg/kg and 300 or 600 mg were examined. Safety of Cirm alone was assessed during the first 28 days, then Ibr was started at approved doses for each indication. Cirm 600 mg IV q2wks x3 then q4wks in combination with Ibr starting day 0 was chosen as the recommended dosing regimen for use in Part 2 (Expansion) and Part 3 (CLL only, Cirm/Ibr vs. Ibr alone). Results: Twelve evaluable MCL pts were enrolled into Part 1, and 5 into Part 2. Median number of prior regimens was 2 (1-5), including pts relapsing after Ibr (4), auto-SCT (3), auto-SCT/ allo-SCT (1), auto-SCT/CAR-T (1). In CLL, 34 evaluable pts (12 TN and 22 RR) enrolled into Part 1 (18) or Part 2 (16). At least 74% of CLL pts in Parts 1 and 2 were high risk as determined by unmutated IGHV, del17p, and/or del11q. In Part 3, 22 evaluable pts received Cirm/Ibr (15) or Ibr (7). As of the 30OCT2020 safety cut-off for MCL and CLL, common TEAEs (all grades) included diarrhea (41%), contusion (39%), fatigue (39%), URI (31%), hypertension (25%) arthralgia (23%). Grade ≥3 neutropenia was 13% and thrombocytopenia 1%. There were no Cirm dose reductions or discontinuations for toxicity. Overall, Cirm did not appear to negatively impact the safety of Ibr. Efficacy (MCL): As of the 02FEB2021 efficacy cutoff, the best response of 17 evaluable pts in Parts 1 and 2 included an objective response rate (ORR) of 82%, 41% CR/CMR, 41% PR, 12% SD, and 6% PD. CR/CMR remain durable from 8-28+ mos. Most responses occurred rapidly after ̃3 mos of Cirm/Ibr. Notably, responses were achieved in all pts who received prior SCT+/- CAR-T (4CR, 1PR) or prior Ibr (2CR, 2PR). At a median follow-up of 14.6 mos, the median PFS (mPFS) had not been reached (NR) (95% CI: 17.5, NA). Efficacy (CLL): The best response of 34 evaluable pts in Parts 1 and 2 included 91% ORR, 3% CR, 88% PR/PR-L, 9% SD, 0% PD. In Part 3, both arms achieved 100% ORR (all PRs). At a median follow-up of 20.2 mos, the mPFS was NR (95% CI: NA, NA), and the PFS estimate at 24 months was 95% for R/R, and 87% for TN, respectively, for evaluable CLL pts receiving Cirm/Ibr. Conclusions: Cirm/Ibr is a well-tolerated, active regimen in both MCL and CLL. For MCL, the mPFS of NR (95% CI: 17.5, NA) and CRR (41%), with all CRs remaining without PD, compare favorably to mPFS of 12.8 mos (95% CI 8.5-16.6) and CRR (20%) reported for single agent Ibr (Rule 2017). For CLL, the high ORR and PFS are encouraging, particularly for RR CLL. The study is ongoing, with MCL enrollment expanded to study Cirm + Ibr in pts who have had a suboptimal response to an Ibr regimen, or who have failed other approved BTKi agents. Clinical trial information: NCT03088878.

Outcomes of Adults With Relapsed/Refractory Acute Myeloid Leukemia Treated With Venetoclax Plus Hypomethylating Agents at a Comprehensive Cancer Center

Relapsed/refractory acute myeloid leukemia (AML) is a devastating disease with a poor prognosis and represents a major unmet medical need. We report on a real-world academic center experience of treating 25 patients with relapsed/refractory AML using venetoclax in combination with decitabine or azacitidine, which is not otherwise widely evaluated in the current literature. Our patients come from a large, socioeconomically and geographically diverse area including the majority of Northern California. Most had ELN Adverse Risk (52%) or Intermediate Risk (44%) AML, and most had an ECOG Performance Status of 1 (64%). Over half (52%) had prior hypomethylating agent exposure, and 40% had Secondary AML. We observed an overall response rate of 52%, with eight patients (32%) achieving composite complete remission. Median overall survival was 5.5 months, and for patients achieving composite complete remission this was 21.6 months. One-year estimated overall survival was 38%. Three patients were able to proceed directly to stem cell transplant for consolidation, and all three were alive at last follow-up, ranging 13.8–24.0 months. We found venetoclax in combination with hypomethylating agents to be well tolerated and potentially efficacious in securing long-term remissions for patients with relapsed/refractory AML.

Retrospective Analysis of Adult Patients With Relapsed/Refractory Acute Myeloid Leukemia Treated with FLAG at a Comprehensive Cancer Center

BACKGROUND

FLAG ± Ida (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin), is a salvage chemotherapy regimen for relapsed or refractory (R/R) acute myeloid leukemia (AML), with complete remission (CR) rates historically ranging from 52% to 63%. We review the outcomes for patients with R/R AML treated with FLAG ± Ida at the University of California Davis Comprehensive Cancer Center.

PATIENTS AND METHODS

Adult patients (≥ 18 years) with R/R AML who received FLAG or FLAG + Ida from January 1, 2012 to October 31, 2016 were identified via chart review. Outcomes evaluated were CR, CR with incomplete hematologic recovery (CRi), overall response rate, overall survival (OS), relapse-free survival, and adverse events.

RESULTS

Forty-two patients were included. The median age was 52 years (range, 23-73 years), and 57% were male. Sixteen (38.1%) patients had relapsed disease, and 26 (61.9%) had refractory disease. Most (n = 35; 83.3%) patients had European LeukemiaNet intermediate-risk AML. Responses were CR in 20 (47.6%) and CRi in 6 (14.3%). The median OS was 10 months (range, 0.8-51 months), and the median relapse-free survival was 12 months (range, 1-51 months) for responders. The median OS for patients who achieved CR was not reached, and the estimated 48-month survival rate was 56%. The median OS after CRi or no response was 3.47 and 2.17 months, respectively. The median OS was not significantly different when censored for stem cell transplant following chemotherapy, nor with use/deferral of idarubicin. The most common adverse effects were pancytopenia and infection.

CONCLUSION

Patient outcomes after treatment with FLAG ± Ida for R/R AML remain similar to prior reports, confirming its role as a salvage regimen for these patients.

Efficacy and toxicity of a CD22-targeted antibody-saporin conjugate in a xenograft model of non-Hodgkin's lymphoma

Antibody drug conjugates (ADCs) can deliver potent drugs to cancer cells by employing the specificity of monoclonal antibodies (mAbs). ADCs have demonstrated significant anticancer activity and, in 2011, brentuximab vedotin has been approved by the FDA for the treatment of Hodgkin's and anaplastic large cell lymphomas. CD22 is an ideal target for ADC against B-cell malignancies because of its lineage-specific expression and rapid internalization upon antibody binding. In this study, we evaluated the anti-CD22 mAb HB22.7 as a vehicle for the targeted delivery of the potent toxin saporin (SAP). In vitro, HB22.7-SAP was cytotoxic against a panel of non-Hodgkin's lymphoma (NHL) cell lines representing the most common types of the disease. Moreover, in a xenograft model of NHL, HB22.7-SAP significantly inhibited the growth of established lesions and completely prevented tumor development when treatment was initiated within 24 h from tumor-cell inoculation. HB22.7-SAP had no significant in vivo toxicity. In conclusion, HB22.7 constitutes a potential platform for CD22-targeted ADCs.

Clinical activity of cirmtuzumab, an anti-ROR1 antibody, in combination with ibrutinib: Interim results of a phase Ib/II study in mantle cell lymphoma (MCL) or chronic lymphocytic leukemia (CLL)

8036

Background: ROR1 is an onco-embryonic tyrosine kinase receptor that is re-expressed at high levels on many hematologic and solid cancers but not on normal adult tissues. ROR1 binds Wnt5a, resulting in increased tumor growth and survival, cancer cell stemness and epithelial mesenchymal transition. Cirmtuzumab (Cirm) is a humanized monoclonal antibody designed to inhibit the tumor promoting activity of ROR1. In this study, we examined the safety and efficacy of Cirm in combination with ibrutinib (Ibr) in MCL or CLL. Methods: As of Jan 29, 2020, 12 pts with relapsed refractory (RR) MCL were enrolled into Part 1 Dose Escalation (DE). All MCL pts had stage 3/ 4 at original diagnosis, 25% had bulky tumor at study entry, 58% had intermediate/high risk MIPI scores and the majority (83%) had ≥ 2 prior regimens. 34 pts with CLL [12 treatment naïve (TN) and 22 RR pts] enrolled into Part 1 DE (n = 18) or Part 2 Expansion (n = 16). At least 79% of CLL pts were high risk as determined by unmutated IGHV, 17p/p53 loss, and/or del 11q. DE pts received Cirm IV q2wks x 3-5 doses then q4wks plus Ibr (starting D28). Following DE, Cirm 600mg IV q2wks x3 then q4wks plus Ibr (420mg/day CLL or 560mg/day MCL) was chosen for Expansion. Results: Safety : only grade 1/ 2 AEs were reported as possibly related to Cirm alone, whereas the safety profile attributed to Ibr or Ibr / Cirm was similar to published data, with no new or unexpected events. Efficacy for MCL: 83% ORR, 33% (4) CR, 50% (6) PR, 17% (2) SD. CRs were achieved at a median of 3.6 mos in heavily pretreated pts, including 2 with bulky disease > 5cm. Prior therapy of the 4 CR pts: 2 pts failed R-Ibr (7-10 mos) and R-hyperCVAD, 1 pt, auto-SCT and allo-SCT, 1 pt, auto-SCT and CAR-T. Efficacy for CLL : 88% ORR (92% TN, 86% RR), 3% (1) CR, 85% (22) PR/ (7) PR-L, 12% (4) SD. In addition, 3 PR pts with CLL met criteria for “Clinical CR, bone marrow biopsy not performed”. The pt achieving a CR had RR disease with del 11q; this pt remains in remission > 6 mos after stopping all therapy. At a median follow-up of 9.9 mos, 100% of CLL pts are free of disease progression and > 82% remain on study. Conclusions: Cirm in combination with Ibr is a well-tolerated and active regimen for RR MCL and TN or RR CLL. In this evaluation of 46 pts, the ORR and PFS continue to improve with longer follow-up and additional pts, supporting continued investigation of this regimen in ROR1 expressing tumors. This study is ongoing and enrolling an Expansion arm for MCL pts and an open-label randomized Phase 2 in CLL pts comparing Ibr alone to Cirm /Ibr. Clinical trial information: NCT03088878 .

A phase I pharmacokinetic study of belinostat in patients with advanced cancers and varying degrees of liver dysfunction

AIMS

The histone deacetylase inhibitor belinostat has activity in various cancers. Because belinostat is metabolized by the liver, reduced hepatic clearance could lead to excessive drug accumulation and increased toxicity. Safety data in patients with liver dysfunction are needed for this drug to reach its full potential in the clinic.

METHODS

We performed a phase 1 trial to determine the safety, maximum tolerated dose (MTD) and pharmacokinetics of belinostat in patients with advanced cancer and varying degrees of liver dysfunction.

RESULTS

Seventy-two patients were enrolled and divided into cohorts based on liver function. In patients with mild dysfunction, the MTD was the same as the recommended phase 2 dose (1000 mg/m2 /day). Belinostat was well tolerated in patients with moderate and severe liver dysfunction, although the trial was closed before the MTD in these cohorts could be determined. The mean clearance of belinostat was 661 mL/min/m2 in patients with normal liver function, compared to 542, 505 and 444 mL/min/m2 in patients with mild, moderate and severe hepatic dysfunction. Although this trial was not designed to assess clinical activity, of the 47 patients evaluable for response, 13 patients (28%) experienced stable disease.

CONCLUSION

While a statistically significant difference in clearance indicates increased belinostat exposure with worsening liver function, no relationship was observed between belinostat exposure and toxicity. An assessment of belinostat metabolites revealed significant differences in metabolic pathway capability in patients with differing levels of liver dysfunction. Further studies are needed to establish formal dosing guidelines in this patient population.

A Phase I Study of the Combination of Rituximab and Ipilimumab in Patients with Relapsed/Refractory B-Cell Lymphoma

PURPOSE

Based on the potential for ipilimumab (I) to augment T-cell activation, we hypothesize that ipilimumab would augment the efficacy of rituximab (R) in patients with relapsed/refractory (R/R) CD20⁺non-Hodgkin's lymphoma (NHL). This phase I study aimed to identify a recommended phase 2 dose, document toxicities, and preliminarily assess efficacy and potential predictive biomarkers.

PATIENTS AND METHODS

Thirty-three patients with R/R CD20⁺B-cell lymphoma received R at 375 mg/m²weekly for 4 weeks and I at 3 mg/kg on day 1 and every 3 weeks for four doses. Responding patients went on to maintenance with each agent given every 12 weeks. To facilitate correlative analysis, the expansion phase randomized patients to simultaneous R+I versus R with I delayed 2 weeks.

RESULTS

Toxicity was manageable; no dose-limiting toxicity was observed at the doses studied. When considering the entire cohort, efficacy was modest, with an objective response rate (ORR) of 24% and median progression-free survival (PFS) of 2.6 months. However, in follicular lymphoma patients, the ORR was 58% with a median PFS of 5.6 months. The randomized comparison of R with R+I demonstrated that R+I resulted in more effective B-cell depletion (BCD). Both B-cell depletion and the ratio of CD45RA^-regulatory T cell (Treg) to Treg were associated with response at all time points.

CONCLUSIONS

The combination of R+I has manageable toxicity and encouraging efficacy in R/R follicular lymphoma. The ratio of CD45RA^-Tregs to total Tregs, and peripheral BCD should be studied further as potential predictors of response.

Treatment with FLAG followed by second allogeneic stem cell transplant for relapsed acute myeloid leukemia and myelodysplastic syndrome

e18503

Background: There is no standard treatment for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) relapsing after allogeneic stem cell transplant (SCT). Options include combination chemotherapy, withdrawal of immunosuppression, donor lymphocyte infusion (DLI), and second SCT. Previous studies have used fludarabine, cytarabine, and granulocyte colony stimulating factor (FLAG) or second SCT separately for salvage therapy. Our institution uses FLAG followed by SCT from the same donor (FLAG/SCT) in this setting. We report a retrospective study of FLAG/SCT in MDS and AML patients relapsed after SCT. Methods: Patients who received FLAG/SCT for treatment of relapsed AML or MDS between 2009 and 2018 were identified using the bone marrow transplant database at University of California Davis. Their baseline characteristics and outcomes were determined using the electronic medical record. Descriptive statistics and Kaplan-Meier survival analysis were used to describe patients, rates of graft-versus-host disease (GvHD) and estimate survival times. Results: Nineteen patients received FLAG/SCT for AML (n=18) and MDS (n=1). Median time to relapse from first SCT was 145 days (range 41 to 960 days). Prior to FLAG/SCT, 17 patients had medullary relapse (median bone marrow blasts 27%; range 7-85%). Two patients had extramedullary relapse. Eighteen (94.7%) patients achieved complete remission (CR) after FLAG/SCT. Median follow-up time was 354 days from the first day of FLAG/SCT (range 7 to 2144 days). Six patients (31.6%) relapsed with median time to relapse of 334 days (range 78 to 679 days) after treatment. Overall survival at 2 years was 52.5%. Causes of death were relapsed AML (n=4; 21.1%), infection (n=4; 21.1%) complications of GvHD (n=3,15.8 %), and brain herniation (n=1, 5.3%). Acute GvHD grade I-IV and new onset chronic GvHD occurred in thirteen (68.4%) and eight patients (42.1%), respectively. Conclusions: FLAG/SCT for AML and MDS relapsing after SCT resulted in a high remission rate. The overall survival of over two years suggests that the second SCT augmented the graft versus leukemia effect. The GvHD rate increased after second SCT, but the rate and severity were manageable. FLAG/ SCT is a reasonable option for relapsed AML and MDS after SCT.

A Protective Role of Aryl Hydrocarbon Receptor Repressor in Inflammation and Tumor Growth

The aryl hydrocarbon receptor (AhR) is known for mediating the toxicity of environmental pollutants such as dioxins and numerous dioxin-like compounds, and is associated with the promotion of various malignancies, including lymphoma. The aryl hydrocarbon receptor repressor (AhRR), a ligand-independent, transcriptionally inactive AhR-like protein is known to repress AhR signaling through its ability to compete with the AhR for dimerization with the AhR nuclear translocator (ARNT). While AhRR effectively blocks AhR signaling, several aspects of the mechanism of AhRR’s functions are poorly understood, including suppression of inflammatory responses and its putative role as a tumor suppressor. In a transgenic mouse that overexpresses AhRR (AhRR Tg) we discovered that these mice suppress 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)- and inflammation-induced tumor growth after subcutaneous challenge of EL4 lymphoma cells. Using mouse embryonic fibroblasts (MEF) we found that AhRR overexpression suppresses the AhR-mediated anti-apoptotic response. The AhRR-mediated inhibition of apoptotic resistance was associated with a suppressed expression of interleukin (IL)-1β and cyclooxygenase (COX)-2, which was dependent on activation of protein kinase A (PKA) and the CAAT-enhancer-binding protein beta (C/EBPβ). These results provide mechanistic insights into the role of the AhRR to suppress inflammation and highlight the AhRR as a potential therapeutic target to suppress tumor growth.

A purified, fermented, extract of Triticum aestivum has lymphomacidal activity mediated via natural killer cell activation

Non-Hodgkin lymphoma (NHL) affects over 400,000 people in the United States; its incidence increases with age. Treatment options are numerous and expanding, yet efficacy is often limited by toxicity, particularly in the elderly. Nearly 70% patients eventually die of the disease. Many patients explore less toxic alternative therapeutics proposed to boost anti-tumor immunity, despite a paucity of rigorous scientific data. Here we evaluate the lymphomacidal and immunomodulatory activities of a protein fraction isolated from fermented wheat germ. Fermented wheat germ extract was produced by fermenting wheat germ with Saccharomyces cerevisiae. A protein fraction was tested for lymphomacidal activity in vitro using NHL cell lines and in vivo using mouse xenografts. Mechanisms of action were explored in vitro by evaluating apoptosis and cell cycle and in vivo by immunophenotyping and measurement of NK cell activity. Potent lymphomacidal activity was observed in a panel of NHL cell lines and mice bearing NHL xenografts. This activity was not dependent on wheat germ agglutinin or benzoquinones. Fermented wheat germ proteins induced apoptosis in NHL cells, and augmented immune effector mechanisms, as measured by NK cell killing activity, degranulation and production of IFNγ. Fermented wheat germ extract can be easily produced and is efficacious in a human lymphoma xenograft model. The protein fraction is quantifiable and more potent, shows direct pro-apoptotic properties, and enhances immune-mediated tumor eradication. The results presented herein support the novel concept that proteins in fermented wheat germ have direct pro-apoptotic activity on lymphoma cells and augment host immune effector mechanisms.

Long-term analysis of phase II studies of single-agent lenalidomide in relapsed/refractory mantle cell lymphoma

Mantle cell lymphoma (MCL) is a type of non-Hodgkin lymphoma (NHL) with aggressive disease characteristics resulting in multiple relapses after initial treatment. Lenalidomide is an immunomodulatory agent approved in the US for patients with relapsed/refractory MCL following bortezomib based on results from 3 multicenter phase II studies (2 including relapsed/refractory aggressive NHL and 1 focusing on MCL post-bortezomib). The purpose of this report is to provide longer follow-up on the MCL-001 study (follow-ups were 6.8 [NHL-002], 7.6 [NHL-003], and 52.2 [MCL-001] months). The 206 relapsed MCL patients treated with single-agent lenalidomide (25 mg/day PO, days 1 to 21 every 28-days) had a median age of 67 years (63% ≥65 years), 91% with stage III/IV disease, and 50% with ≥4 previous treatment regimens. With a median follow-up of X, the combined best overall response rate (ORR) was 33% (including 11% with complete remission [CR]/CR unconfirmed CRu). Lenalidomide produced rapid and durable responses with a median time to response of 2.2 months and median duration of response (DOR) of 16.6 months (95% CI: 11.1%-29.8%). The safety profile was consistent and manageable; myelosuppression was the most common adverse event (AE). Overall, single-agent lenalidomide showed consistent efficacy and safety in multiple phase II studies of heavily pretreated patients with relapsed/refractory MCL, including those previously treated with bortezomib.

The HB22.7-vcMMAE antibody-drug conjugate has efficacy against non-Hodgkin lymphoma mouse xenografts with minimal systemic toxicity

In this study, HB22.7, an anti-CD22 monoclonal antibody, was used for specific, targeted delivery of monomethyl auristatin E (MMAE) to non-Hodgkin lymphoma (NHL). MMAE was covalently coupled to HB22.7 through a valine-citrulline peptide linker (vc). Maleimide-functionalized vcMMAE (mal-vcMMAE) was reacted with thiols of the partially reduced mAb. Approximately 4 molecules of MMAE were conjugated to HB22.7 as determined by residual thiol measurement and hydrophobic interaction chromatography-HPLC (HIC-HPLC). HB22.7-vcMMAE antibody-drug conjugate (ADC) retained its binding to Ramos NHL cells and also exhibited potent and specific in vitro cytotoxicity on a panel of B cell NHL cell lines with IC50s of 20-284 ng/ml. HB22.7-vcMMAE also showed potent efficacy in vivo against established NHL xenografts using the DoHH2 and Granta 519 cell lines. One dose of the ADC induced complete and persistent response in all DoHH2 xenografts and 90 % of Granta xenografts. Minimal toxicity was observed. In summary, HB22.7-vcMMAE is an effective ADC that should be evaluated for clinical translation.

Novel Targeted Therapy for Precursor B Cell Acute Lymphoblastic Leukemia: anti-CD22 Antibody-MXD3 Antisense Oligonucleotide Conjugate

The exponential rise in molecular and genomic data has generated a vast array of therapeutic targets. Oligonucleotide-based technologies to down regulate these molecular targets have promising therapeutic efficacy. However, there is relatively limited success in translating this into effective in vivo cancer therapeutics. The primary challenge is the lack of effective cancer cell-targeted delivery methods, particularly for a systemic disease such as leukemia. We developed a novel leukemia-targeting compound composed of a monoclonal antibody directly conjugated to an antisense oligonucleotide (ASO). Our compound uses an ASO that specifically targets the transcription factor MAX dimerization protein 3 (MXD3), which was previously identified to be critical for precursor B cell (preB) acute lymphoblastic leukemia (ALL) cell survival. The MXD3 ASO was conjugated to an anti-CD22 antibody (αCD22 Ab) that specifically targets most preB ALL. We demonstrated that the αCD22 Ab-ASO conjugate treatment showed MXD3 protein knockdown and leukemia cell apoptosis in vitro. We also demonstrated that the conjugate treatment showed cytotoxicity in normal B cells, but not in other hematopoietic cells, including hematopoietic stem cells. Furthermore, the conjugate treatment at the lowest dose tested (0.2mg/kg Ab for 6 doses - twice a week for 3 weeks) more than doubled the mouse survival time in both Reh (median survival time 20.5 vs. 42.5 days, p<0.001) and primary preB ALL (median survival time 29.3 vs. 63 days, p<0.001) xenograft models. Our conjugate that uses αCD22 Ab to target the novel molecule MXD3, which is highly expressed in preB ALL cells, appears to be a promising novel therapeutic approach.

A phase I pharmacodynamic study of GTI-2040, an antisense oligonucleotide against ribonuclotide reductase, in acute leukemias: a California Cancer Consortium study

We performed a phase I study of GTI-2040, an antisense oligonucleotide against ribonucleotide reductase mRNA, on a novel dosing schedule of days 1-4 and 15-18 by continuous infusion to examine efficacy and tolerability in patients with leukemia. A dose of 11 mg/kg/d was safely reached. Dose-limiting toxicities (DLTs) at the higher levels included elevated troponin I and liver function enzymes. There were no objective responses to GTI-2040 in this study; 7/24 patients were able to complete the predetermined three infusion cycles. Pharmacokinetic and pharmacodynamic studies were performed, indicating a trend towards increasing intracellular drug levels and decreasing RRM2 gene expression with increasing doses. This dose schedule may be considered if appropriate combinations are identified in preclinical studies.

Evaluation of the International Prognostic Score (IPS-7) and a Simpler Prognostic Score (IPS-3) for advanced Hodgkin lymphoma in the modern era

The International Prognostic Score (IPS-7) is the most commonly used risk stratification tool for advanced Hodgkin lymphoma (HL), however recent studies suggest the IPS-7 is less discriminating due to improved outcomes with contemporary therapy. We evaluated the seven variables for IPS-7 recorded at study entry for 854 patients enrolled on Eastern Cooperative Oncology Group 2496 trial. Univariate and multivariate Cox models were used to assess their prognostic ability for freedom from progression (FFP) and overall survival (OS). The IPS-7 remained prognostic however its prognostic range has narrowed. On multivariate analysis, two factors (age, stage) remained significant for FFP and three factors (age, stage, haemoglobin level) for OS. An alternative prognostic index, the IPS-3, was constructed using age, stage and haemoglobin level, which provided four distinct risk groups [FFP (P = 0·0001) and OS (P < 0·0001)]. IPS-3 outperformed the IPS-7 on risk prediction for both FFP and OS by model fit and discrimination criteria. Using reclassification calibration, 18% of IPS-7 low risk patients were re-classified as intermediate risk and 13% of IPS-7 intermediate risk patients as low risk. For patients with advanced HL, the IPS-3 may provide a simpler and more accurate framework for risk assessment in the modern era. Validation of these findings in other large data sets is planned.

Efficacy of Combined Histone Deacetylase and Checkpoint Kinase Inhibition in a Preclinical Model of Human Burkitt Lymphoma

Checkpoint kinase inhibition has been studied as a way of enhancing the effectiveness of DNA-damaging agents. More recently, histone deacetylase inhibitors have shown efficacy in several cancers, including non-Hodgkin lymphoma. To evaluate the effectiveness of this combination for the treatment of lymphoma, we examined the combination of AR42, a histone deacetylase inhibitor, and checkpoint kinase 2 (CHEK2) inhibitor II in vitro and in vivo. The combination resulted in up to 10-fold increase in potency in five Burkitt lymphoma cell lines when compared with either drug alone. Both drugs inhibited tumor progression in xenograft models, but the combination was more effective than either agent alone, resulting in regression of established tumors. No toxicity was observed. These results suggest that the combination of histone deacetylase inhibition and checkpoint kinase inhibition represent an effective and nontoxic treatment option that should be further explored in preclinical and clinical studies.

Randomized Phase III Trial Comparing ABVD Plus Radiotherapy With the Stanford V Regimen in Patients With Stages I or II Locally Extensive, Bulky Mediastinal Hodgkin Lymphoma: A Subset Analysis of the North American Intergroup E2496 Trial

PURPOSE

The phase III North American Intergroup E2496 Trial (Combination Chemotherapy With or Without Radiation Therapy in Treating Patients With Hodgkin's Lymphoma) compared doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) with mechlorethamine, doxorubicin, vincristine, bleomycin, vinblastine, etoposide, and prednisone (Stanford V). We report results of a planned subgroup analysis in patients with stage I or II bulky mediastinal Hodgkin lymphoma (HL).

PATIENTS AND METHODS

Patients were randomly assigned to six to eight cycles of ABVD every 28 days or Stanford V once per week for 12 weeks. Two to 3 weeks after completion of chemotherapy, all patients received 36 Gy of modified involved field radiotherapy (IFRT) to the mediastinum, hila, and supraclavicular regions. Patients on the Stanford V arm received IFRT to additional sites ≥ 5 cm at diagnosis. Primary end points were failure-free survival (FFS) and overall survival (OS).

RESULTS

Of 794 eligible patients, 264 had stage I or II bulky disease, 135 received ABVD, and 129 received Stanford V. Patient characteristics were matched. The overall response rate was 83% with ABVD and 88% with Stanford V. At a median follow-up of 6.5 years, the study excluded a difference of more than 21% in 5-year FFS and more than 16% in 5-year OS between ABVD and Stanford V (5-year FFS: 85% v 79%; HR, 0.68; 95% CI, 0.37 to 1.25; P = .22; 5-year OS: 96% v 92%; HR, 0.49; 95% CI, 0.16 to 1.47; P = .19). In-field relapses occurred in < 10% of the patients in each arm.

CONCLUSION

For patients with stage I or II bulky mediastinal HL, no substantial statistically significant differences were detected between the two regimens, although power was limited. To the best of our knowledge, this is the first prospective trial reporting outcomes specific to this subgroup, and it sets a benchmark for comparison of ongoing and future studies.

A phase 2 study of belinostat (PXD101) in patients with relapsed or refractory acute myeloid leukemia or patients over the age of 60 with newly diagnosed acute myeloid leukemia: a California Cancer Consortium Study

We performed a phase II study of belinostat in patients with acute myeloid leukemia (AML). In this open label phase II study (NCT00357032), patients with relapsed/refractory AML, or newly diagnosed patients with AML over the age of 60, were eligible. Belinostat was administered intravenously (IV) at a dose of 1000 mg/m(2) daily on days 1-5 of a 21-day cycle until progression or unacceptable toxicity. The primary endpoint was complete response (CR) rate, with secondary endpoints of overall response rate (CR + partial response [PR]), time to treatment failure (TTF), overall survival and safety. Twelve eligible patients with AML were enrolled, of whom six had received at least one prior line of therapy. No CR or PR was seen. Four patients had stable disease for at least five cycles. Grade 3 non-hematological toxicities occurred in four patients. Belinostat as monotherapy has minimal single-agent effect in AML on this dosing schedule.

Everolimus for patients with mantle cell lymphoma refractory to or intolerant of bortezomib: multicentre, single-arm, phase 2 study

The multicentre, open-label, two-stage, single-arm, phase 2, PILLAR (PIvotaL Lymphoma triAls of RAD001)-1 study (NCT00702052) assessed the efficacy and safety of everolimus 10 mg/d in adults with confirmed mantle cell lymphoma (MCL) refractory to or intolerant of bortezomib who received ≥1 other antineoplastic agent, either separately or in combination with bortezomib. Primary endpoint was overall response rate (ORR) per investigator review according to the response criteria for malignant lymphoma. Secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. Fifty-eight patients were enrolled from August 2008-January 2011. Five partial responses were observed (ORR 8·6%; 90% confidence interval [CI] 3·5-17·3%); the study did not meet the prespecified objective of ≥8 objective responses among 57 patients. Median PFS and OS were 4·4 months (95% CI 3·5-6·1) and 16·9 months (95% CI 14·4-29·9), respectively. Grade 3/4 non-haematological toxicities occurred in 70·7% of patients. Based on laboratory values, grade 3/4 thrombocytopenia, neutropenia and anaemia occurred in 13·8%, 13·8% and 8·6% of patients, respectively. Everolimus demonstrated modest activity and acceptable tolerability in heavily pretreated patients with MCL refractory to or intolerant of bortezomib. Future studies evaluating everolimus in a less refractory population or in combination with other targeted therapies in refractory MCL are warranted.

Lenalidomide plus rituximab can produce durable clinical responses in patients with relapsed or refractory, indolent non-Hodgkin lymphoma

This phase II study evaluated the safety and efficacy of lenalidomide in combination with rituximab in patients with relapsed/refractory, indolent non-Hodgkin lymphoma (NHL). Patients were treated with daily lenalidomide in 28-d cycles and weekly rituximab for 4 weeks. Lenalidomide was continued until progression or unacceptable toxicity. Twenty-two patients were assessed for FCGR3A polymorphisms. Thirty patients were enrolled; 27 were evaluable for response. The overall response rate (ORR) was 74% including 44% complete responses (CR); median progression-free survival (PFS) was 12·4 months. The 13 rituximab refractory patients had an ORR of 61·5% (four CR/unconfirmed CR). The ORR was 77% in the 22 follicular lymphoma patients (nine CR/unconfirmed CR). At a median follow-up time of 43 months, the median duration of response and time to next therapy were 15·4 and 37·4 months, respectively. Most common grade 3/4 adverse events were lymphopenia (45%), neutropenia (55%), fatigue (23%) and hyponatraemia (9%). The ORR and PFS in patients with low-affinity FCGR3A polymorphisms (F/F and F/V) suggest that lenalidomide may improve the activity of rituximab in these patients. These data suggest that combining lenalidomide with rituximab can produce durable responses with acceptable toxicity in patients with indolent NHL.

B cell reductive therapy in the treatment of autoimmune diseases: A focus on monoclonal antibody treatment of rheumatoid arthritis

The therapeutic approach to patients with autoimmune disorders is in the midst of a dramatic change. Monoclonal antibody technology has allowed us to dissect and now manipulate the human immune system with greater precision. It is now widely recognized that B lymphocytes play a role in the pathogenesis of many autoimmune diseases, though the extent and contribution is a matter of debate and active investigation. There is emerging data to suggest that both antibody-dependent and independent mechanisms contribute to disease pathogenesis. However, given the heterogeneous nature of autoimmune diseases, and the varied responses to B lymphocyte reduction, the role of B lymphocytes is likely disease-specific. The two clinical trials discussed in this review demonstrate remarkable consistency in the ability of B cell reduction to ameliorate the clinical manifestations of rheumatoid arthritis with minimal toxicity. B lymphocyte targeted approaches to autoimmune disease in general, and RA specifically, will not only provide an effective and potentially less toxic alternative treatment option, but also allow for a better understanding of the pathogenesis of these complex and morbid diseases.

Combined analysis of single-agent lenalidomide in relapsed/refractory mantle cell lymphoma

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Background: Mantle cell lymphoma (MCL) is an aggressive form of non-Hodgkin lymphoma (NHL) with poor prognosis. The immunomodulatory agent lenalidomide shows consistent activity with tolerable safety in multiple phase II studies of relapsed/refractory aggressive NHL (NHL-002 and NHL-003) and MCL post-bortezomib (MCL-001). This pooled analysis further examined the efficacy and safety of single-agent lenalidomide in patients with relapsed/refractory MCL. Methods: Single-agent lenalidomide was given 25 mg/d PO on days 1-21 of 28-day cycles as tolerated for 52 weeks (NHL-002) or until disease progression (NHL-003 and MCL-001). All MCL patients received ≥1 prior treatment, including bortezomib in MCL-001. Efficacy data were examined by independent central review for MCL-001 and NHL-003 and by investigators for NHL-002. Results: 206 patients with relapsed/refractory MCL were studied. The median age was 67 y (range 33-84; 63% ≥65 y), 91% stage III/IV disease and 51% had received ≥4 prior regimens (76% prior bortezomib). Overall response rate (ORR) with lenalidomide was 32% (10% CR/CRu), with a median time to response of 2.1 months and median duration of response (DOR) of 16.6 months (not yet reached in patients with CR/CRu; Table). Kaplan-Meier estimates for median PFS and OS were 5.4 and 23.9 months, respectively. Mean daily dose of lenalidomide was 21 mg. Grade 3/4 AEs included neutropenia (44%), thrombocytopenia (29%), anemia (11%), and fatigue (7%). Other any-grade AEs included tumor flare reaction (7%), venous thromboembolic events (7%), and invasive second primary malignancies (3%). Conclusions: Lenalidomide produced rapid and durable responses in patients with relapsed/refractory MCL, and exhibited a predictable safety profile among 3 phase II studies of lenalidomide in heavily pretreated patients, including prior treatment with bortezomib. Clinical trial information: MCL-001: NCT00737529; NHL-002: NCT00179660; NHL-003: NCT00413036. [Table: see text]

Randomized phase III trial of ABVD versus Stanford V with or without radiation therapy in locally extensive and advanced-stage Hodgkin lymphoma: an intergroup study coordinated by the Eastern Cooperative Oncology Group (E2496)

PURPOSE

Although ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) has been established as the standard of care in patients with advanced Hodgkin lymphoma, newer regimens have been investigated, which have appeared superior in early phase II studies. Our aim was to determine if failure-free survival was superior in patients treated with the Stanford V regimen compared with ABVD.

PATIENTS AND METHODS

The Eastern Cooperative Oncology Group, along with the Cancer and Leukemia Group B, the Southwest Oncology Group, and the Canadian NCIC Clinical Trials Group, conducted this randomized phase III trial in patients with advanced Hodgkin lymphoma. Stratification factors included extent of disease (localized v extensive) and International Prognostic Factors Project Score (0 to 2 v 3 to 7). The primary end point was failure-free survival (FFS), defined as the time from random assignment to progression, relapse, or death, whichever occurred first. Overall survival, a secondary end point, was measured from random assignment to death as a result of any cause. This design provided 87% power to detect a 33% reduction in FFS hazard rate, or a difference in 5-year FFS of 64% versus 74% at two-sided .05 significance level.

RESULTS

There was no significant difference in the overall response rate between the two arms, with complete remission and clinical complete remission rates of 73% for ABVD and 69% for Stanford V. At a median follow-up of 6.4 years, there was no difference in FFS: 74% for ABVD and 71% for Stanford V at 5 years (P = .32).

CONCLUSION

ABVD remains the standard of care for patients with advanced Hodgkin lymphoma.

Efficacy of a CD22-targeted antibody-saporin conjugate in a xenograft model of precursor-B cell acute lymphoblastic leukemia

Targeted therapies, such as those using imatinib and rituximab, have revolutionized the treatment of Philadelphia chromosome-positive and CD20-positive acute lymphoblastic leukemia (ALL) respectively, yet these therapies are effective in only a subset of patients and remission is generally not durable. The next generation of targeted therapies includes the use of antibodies conjugated to potent cytotoxic agents and are classified as antibody drug conjugates (ADC). For B-lineage ALL, CD22 is an ideal target for ADC therapy because it is expressed on the majority of B-lineage ALL cells and because antibody binding mediates receptor internalization. HB22.7-SAP is a conjugate of our anti-CD22 monoclonal antibody (mAb), HB22.7, and the ribosome inhibiting protein, saporin (SAP). In vitro, HB22.7-SAP effectively bound to CD22 on the surface of pre-B ALL cell lines and exhibited potent and specific cytotoxicity. In a NOD/SCID xenograft mouse model of pre-B ALL, when compared to the vehicle-treated control, HB22.7-SAP increased the median survival time from 20 days to over 50 days without significant toxicity.

CD22 antigen is broadly expressed on lung cancer cells and is a target for antibody-based therapy

Most patients with lung cancer still die from their disease, necessitating additional options to improve treatment. Here, we provide evidence for targeting CD22, a cell adhesion protein known to influence B-cell survival that we found is also widely expressed in lung cancer cells. In characterizing the antitumor activity of an established anti-CD22 monoclonal antibody (mAb), HB22.7, we showed CD22 expression by multiple approaches in various lung cancer subtypes, including 7 of 8 cell lines and a panel of primary patient specimens. HB22.7 displayed in vitro and in vivo cytotoxicity against CD22-positive human lung cancer cells and tumor xenografts. In a model of metastatic lung cancer, HB22.7 inhibited the development of pulmonary metastasis and extended overall survival. The finding that CD22 is expressed on lung cancer cells is significant in revealing a heretofore unknown mechanism of tumorigenesis and metastasis. Our work suggests that anti-CD22 mAbs may be useful for targeted therapy of lung cancer, a malignancy that has few tumor-specific targets.

Disulfide cross-linked micelles for the targeted delivery of vincristine to B-cell lymphoma

Vincristine (VCR) is a potent anticancer drug, but its clinical efficacy is limited by neurotoxicity. The field of drug delivery may provide an opportunity to increase the therapeutic index of VCR by delivering the drug specifically to tumor sites while sparing normal tissue. We have recently developed a telodendrimer (PEG(5k)-Cys(4)-L(8)-CA(8)) capable of forming disulfide cross-linked micelles (DCMs) which can encapsulate a variety of chemotherapeutics. In the present study, we encapsulated VCR into these micelles (DCM-VCR) and used them to treat lymphoma bearing mice. DCM-VCR particles have a size of 16 nm, which has been shown to be optimal for their accumulation into tumor via the enhanced permeability and retention (EPR) effect. Compared to our first-generation non-cross-linked micelles (NCMs), DCM-VCR demonstrated greater stability and slower drug release under physiological conditions. In addition, DCM-VCR exhibited a maximum tolerated dose (MTD) of 3.5 mg/kg while the MTD for conventional VCR was only 1.5 mg/kg. Using a near-infrared cyanine dye (DiD) as the surrogate drug, we showed that DCM-VCR accumulated at the tumor site starting 1 h after injection and persisted up to 72 h in lymphoma xenografted nude mice. In an in vivo efficacy study, high dose (2.5 mg/kg) DCM-VCR produced the greatest reduction in tumor volume. High dose DCM-VCR was well tolerated with no significant changes in complete blood count, serum chemistry and histology of the sciatic nerve. Mice treated with an equivalent dose (1 mg/kg) of conventional VCR and DCM-VCR controlled tumor growth equally; however, in combination with on-demand addition of the reducing agent N-acetylcysteine, DCM-VCR exhibited a superior antitumor effect compared to conventional VCR.

The HB22.7 Anti-CD22 monoclonal antibody enhances bortezomib-mediated lymphomacidal activity in a sequence dependent manner

Most non-Hodgkin's lymphomas (NHL) initially respond to chemotherapy, but relapse is common and treatment is often limited by chemotherapy-related toxicity. Bortezomib, is a highly selective proteasome inhibitor with anti-NHL activity; it is currently FDA approved for second-line treatment of mantle cell lymphoma (MCL). Bortezomib exerts its activity in part through the generation of reactive oxygen species (ROS) and also by the induction of apoptosis.We previously validated CD22 as a potential target in treating NHL and have shown that the anti-CD22 ligand blocking antibody, HB22.7, has significant independent lymphomacidal properties in NHL xenograft models. We sought to determine whether or not these agents would work synergistically to enhance cytotoxicity. Our results indicate that treatment of NHL cell lines with HB22.7 six hours prior to bortezomib significantly diminished cell viability. These effects were not seen when the agents were administered alone or when bortezomib was administered prior to HB22.7. Additionally, HB22.7 treatment prior to bortezomib increased apoptosis in part through enhanced ROS generation. Finally, in a mouse xenograft model, administration of HB22.7 followed 24 hours later by bortezomib resulted in 23% smaller tumor volumes and 20% enhanced survival compared to treatment with the reverse sequence. Despite the increased efficacy of HB22.7 treatment followed by bortezomib, there was no corresponding decrease in peripheral blood cell counts, indicating no increase in toxicity. Our results suggest that pre-treatment with HB22.7 increases bortezomib cytotoxicity, in part through increased reactive oxygen species and apoptosis, and that this sequential treatment combination has robust efficacy in vivo.

Geoepidemiology and autoimmune manifestations of lymphoproliferative disorders

The pathogenesis of lymphoproliferative disorders represents an underlying dysfunction in lymphocyte development and homeostasis. This typically manifests with the accumulation of lymphocytes in the bone marrow, peripheral blood or lymph nodes and spleen. It has been hypothesized that the mechanism for elimination of dysfunctional and autoreactive lymphocytes is defective and contributes to the pathogenesis of these disorders. Based on this hypothesis, it would not be surprising to find an increased incidence of autoimmune manifestations that are associated with these disorders. Autoimmune paraneoplastic syndromes (PNS) are often the result of a dysfunctional immune response, which is related to an underlying malignant process. While all the PNS that are associated with lymphoproliferative disorders do not have an autoimmune basis, many do. Here we review the literature of PNS associated with lymphoproliferative disorders. A concise overview of each syndrome is provided with a focus on clinical manifestations, diagnostics, pathophysiology, and treatment. While the treatment is typically directed at managing the underlying lymphoproliferative process, and can be assumed to be case throughout this review, there are exceptions that are described within the context of each disorder.

Treatment of non-Hodgkin's lymphoma xenografts with the HB22.7 anti-CD22 monoclonal antibody and phosphatase inhibitors improves efficacy

PURPOSE

To examine the role of phosphatase inhibition on anti-CD22, HB22.7-mediated lymphomacidal effects.

EXPERIMENTAL DESIGN

CD22 is a cell-surface molecule expressed on most B cell lymphomas (NHL). HB22.7 is an anti-CD22 monoclonal antibody that binds a unique CD22-epitope, blocks ligand binding, initiates signaling, and has demonstrated lymphomacidal activity. The SHP-1 tyrosine phosphatase is associated with the cytoplasmic domain of CD22. Sodium orthovanadate (NaV) is a phosphatase inhibitor. The SHP-1-CD22 interaction presents an opportunity to manipulate CD22-mediated signaling effects. In vitro cell culture assays and in vivo human NHL xenograft studies were used to assess the effects of phosphatase inhibition.

RESULTS

NaV caused dose dependent killing of NHL cells in vitro; when HB22.7 was given with NaV, antibody-mediated cell death was augmented. Flow cytometry showed that NaV-pretreatment resulted in less CD22 internalization after ligation with HB22.7 than did control cells. Studies in mice bearing Raji NHL xenografts showed that the combination of NaV and HB22.7 shrank NHL tumors more rapidly, had a higher complete response rate (80%), and produced the best survival compared to controls; no toxicity was detected. Studies using Raji cells stably transfected with SHP-1DN confirmed that these observations were due to SHP-1 inhibition.

CONCLUSION

The relatively specific association of SHP-1 with CD22 suggests that CD22-specific signal augmentation by phosphatase inhibitors can improve the clinical outcome of anti-CD22 based immunotherapy.