Drug development for recurrent and refractory classical Hodgkin lymphoma

Combining HDAC inhibitors with oncolytic virotherapy for cancer therapy

Histone deacetylase (HDAC) enzymes play a critical role in the epigenetic regulation of cellular functions and signaling pathways in many cancers. HDAC inhibitors (HDACi) have been validated for single use or in combination with other drugs in oncologic therapeutics. An even more novel combination therapy with HDACi is to use them with an oncolytic virus. HDACi may lead to an amplification of tumor-specific lytic effects by facilitating increased cycles of viral replication, but there may also be direct anticancer effects of the drug by itself. Here, we review the molecular mechanisms of anti-cancer effects of the combination of oncolytic viruses with HDACi.

A phase 2 multicenter study of lenalidomide in relapsed or refractory classical Hodgkin lymphoma

Relapsed or refractory (rel/ref) classical Hodgkin lymphoma (cHL) remains a clinical challenge, with limited effective treatment options available after stem cell transplantation. In a multicenter phase 2 study, the efficacy of lenalidomide in rel/ref cHL patients was evaluated at a dose of 25 mg/d on days 1-21 of a 28-day cycle. Patients remained on lenalidomide until disease progression or an unacceptable adverse event (AE) occurred. Thirty-eight cHL patients were enrolled with a median of 4 (range, 2-9) prior therapies; 87% had undergone prior stem cell transplantation and 55% of patients did not respond to their last prior therapy. Of 36 evaluable patients, responses were 1 complete remission (CR), 6 partial remissions (PRs), and 5 patients with stable disease (SD) for ≥ 6 months resulting in an International Working Committee (IWC) objective overall response rate (ORR) of 19% and a cytostatic ORR of 33%. Decreased chemokine (CCL17 and CCL22) plasma levels at 2 weeks were associated with a subsequent response. The treatment was well tolerated, and the most common grade 3/4 AEs were neutropenia (47%), anemia (29%), and thrombocytopenia (18%). Four patients discontinued lenalidomide because of rash, elevated transaminases/bilirubin, and cytopenias. We provide preliminary evidence of lenalidomide's activity in patients with rel/ref cHL, and therefore exploration of lenalidomide in combination with other active agents is warranted. This trial is registered at www.ClinicalTrials.gov as NCT00540007.

The potential of immunomodulatory drugs in the treatment of solid tumors

Lenalidomide (REVLIMID®) CC-5013 (Celgene, NJ, USA) is approved, in both the USA and Europe, in combination with dexamethasone for the treatment of multiple myeloma patients who have received at least one prior therapy, and is rapidly being accepted worldwide for this condition. Lenalidomide is also approved in the USA and Canada for use in transfusion-dependent anemia in patients with low- and intermediate-1-risk myelodysplastic syndromes associated with del (5q) abnormality with or without additional abnormalities. Lenalidomide is an IMiD® immunomodulatory compound, incorporating structural modification of the drug thalidomide, which is active against a wide variety of autoimmune Th-2-dependent disorders, including erythema nodosum of leprosy, leishmaniasis, as well as severe ulcerative disorders such as Behcet's syndrome. Unfortunately, long-term use of thalidomide is limited, particularly by neurotoxicity. To date, results suggest that lenalidomide is more active than thalidomide and does not cause the neurotoxicity seen with thalidomide. Lenalidomide has multiple properties, including anti-inflammatory, antiangiogenic and costimulatory effects, as well as being able to inhibit T-regulatory cells, all of which are properties deemed desirable for anticancer activity. This article covers the evidence that lenalidomide may have a major role in the treatment and control of many cancer types other than del (5q) myelodysplastic syndrome and multiple myeloma.

Targeting macrophages in classical Hodgkin's lymphoma may seem rational, but is it safe?

A few reports have linked increased numbers of tissue macrophages with treatment failure and reduced lifespan in classical Hodgkin's lymphoma (HL) patients. Some investigators even suggested to target the macrophages in HL with biologic therapy, thus eliminating them from the tumor microenvironment. This review explores the risk: benefit equation of such approach as well as what the author believes is the driving force behind the 'great' migration of macrophages in HL. This article unravels the inflammatory pathways and immune alterations in classical HL that lead to a complex network consisting of T-cells, numerous cytokines, macrophages, and other cells. Macrophages are thought to play a crucial role in tumor antigen processing and presentation tasks, Reed-Sternberg (RS) cell phagocytosis, and antibody-dependent cellular cytotoxicity, therefore their extinction may be hazardous. The author believes RS cells should be targeted by the biologics, not the macrophages, and links his hopes with the existing investigational anti-CD30 therapies in relapsed/refractory classical HL.

Class I histone deacetylases 1, 2 and 3 are highly expressed in classical Hodgkin's lymphoma

OBJECTIVE

HDAC inhibitors (HDI) are anti-neoplastic drugs with preliminary successful clinical applications in Hodgkin's lymphoma (HL). Systematic investigations of HDAC expression in HL, based on histology and immunohistochemistry are yet rare.

RESEARCH DESIGN/METHODS

We investigated the expression of HDAC1, 2 and 3 in 283 HL on tissue microarrays.

MAIN OUTCOME MEASURES

Expression of HDAC isoforms was scored in Hodgkin and Reed-Sternberg cells (HRSC) and background infiltrate and compared with freedom of treatment failure (FTF) in 118 cases, for which all data was available.

RESULTS

All analyzable HL expressed the HDAC isoforms 2 (n = 194) and 3 (n = 207) in over 50%, mostly 100%, of HRSC and almost all background lymphocytes. HDAC1 was expressed in 169 of 179 analyzable HL in a mean of 82% and in 172 out of 179 analyzable cases in a mean of 83% of infiltrating lymphocytes. HDAC1 of below 75% in HRSC correlated with worse FTF with 16 out of 32 events, compared with 16 out of 82 in cases with over 75% HDAC1-expressing HRSC.

CONCLUSION

HDAC isoforms 1, 2 and 3 are highly expressed in HL. In addition, decreased HDAC1 expression is accompanied by worse outcome in HL.