Interferon Therapy in Myelofibrosis: Systematic Review and Meta-analysis

Pegylated interferon: the who, why, and how

Interferon alpha (IFN-α) is a fascinating molecule with many biological properties yet to be fully understood. Among these properties, several have demonstrated usefulness for targeting malignant cells, including hematopoietic cells from patients with myeloproliferative neoplasms. Indeed, IFN-α has been used for decades across all myeloproliferative neoplasms, but only recently a new form, ropegIFN-α2b, was approved to treat patients with polycythemia vera. Many phase 2 and more recently phase 3 studies have demonstrated IFN-α's promise in treating patients with essential thrombocythemia and early-stage myelofibrosis. In addition, although not approved in that situation, IFN-α is the only cytoreductive therapy that can be used during pregnancy. Today, IFN-α is a key medicine for polycythemia vera and essential thrombocythemia, while its place in the management of myelofibrosis must be better defined. The advantages of IFN therapy include a well-known safety profile, high rates of clinical and molecular responses, and a unique ability to deeply reduce the mutant allele burden of most of the driver mutations causing myeloproliferative neoplasms. Recent preliminary data from prospective studies suggest that molecular responses may be correlated with prolonged event-free survival, raising the hope that IFN therapy may ultimately alter the natural history of many diseases.

A randomized, double-blind, placebo-controlled phase 3 study to assess efficacy and safety of ropeginterferon alfa-2b in patients with early/lower-risk primary myelofibrosis

Primary myelofibrosis (PMF) is the most aggressive of the myeloproliferative neoplasms and patients require greater attention and likely require earlier therapeutic intervention. Currently approved treatment options are limited in their selective suppression of clonal proliferation resulting from driver- and coexisting gene mutations. Janus kinase inhibitors are approved for symptomatic patients with higher-risk PMF. Additionally, most ongoing clinical studies focus on patients with higher-risk disease and/or high rates of transfusion dependency. Optimal treatment of early/lower-risk PMF remains to be identified and needs randomized clinical trial evaluations. Pegylated interferon alfa is recommended for symptomatic lower-risk PMF patients based on phase 2 non-randomized studies and expert opinion. Ropeginterferon alfa-2b (ropeg) is a new-generation pegylated interferon-based therapy with favorable pharmacokinetics and safety profiles, requiring less frequent injections than prior formulations. This randomized, double-blind, placebo-controlled phase 3 trial will assess its efficacy and safety in patients with "early/lower-risk PMF", defined as pre-fibrotic PMF or PMF at low or intermediate-1 risk according to Dynamic International Prognostic Scoring System-plus. Co-primary endpoints include clinically relevant complete hematologic response and symptom endpoint. Secondary endpoints include progression- or event-free survival, molecular response in driver or relevant coexisting gene mutations, bone marrow response, and safety. Disease progression and events are defined based on the International Working Group criteria and well-published reports. 150 eligible patients will be randomized in a 2:1 ratio to receive either ropeg or placebo. Blinded sample size re-estimation is designed. Ropeg will be administered subcutaneously with a tolerable, higher starting-dose regimen. The study will provide important data for the treatment of early/lower-risk PMF for which an anti-clonal, disease-modifying agent is highly needed.

SOHO State of the Art Update and Next Questions: Novel Therapies for Polycythemia Vera

In the recent years, landmark advancements in the treatment of polycythemia vera (PV) have been achieved. We witnessed the regulatory approval of ropeginterferon and the advanced clinical development of other novel agents that may affect the underlying pathophysiological mechanisms of the disease. Agents with the potential of disease modification may soon overtake preceding treatment options that were based on the patient's age and history of thrombosis. Recent studies using ropeginterferon in low-risk PV patients earlier in the disease course challenge the current treatment paradigm and shift the focus on modifying the course of the disease. Hepcidin mimetics offer an excellent alternative to phlebotomy, providing better quality of life, and may lead to improved outcomes in PV by tight hematocrit control. Novel agents, such as histone deacetylase inhibitors, hold promise to complement the therapeutic landscape of PV and might be particularly promising in rationale combinations. Ruxolitinib is well established as an approved second-line treatment for PV. In the frontline setting, the precise role of ruxolitinib, which also represents an appealing agent in combination regimens, will be determined in ongoing research studies. Longer follow-up is necessary to assess whether novel agents/regimens elicit fewer thromboembolic/ hemorrhagic events and halt disease progression to myelofibrosis and acute myeloid leukemia. We aspire that disease-modifying approaches in PV are on the horizon, and that we will be empowered to ultimately change the natural course of the disease and profoundly impact the lives of PV patients in the near future.

Interferons in the treatment of myeloproliferative neoplasms

Interferons are cytokines with immunomodulatory properties and disease-modifying effects that have been used to treat myeloproliferative neoplasms (MPNs) for more than 35 years. The initial use of interferons was limited due to difficulties with administration and a significant toxicity profile. Many of these shortcomings were addressed by covalently binding polyethylene glycol to the interferon structure, which increases the stability, prolongs activity, and reduces immunogenicity of the molecule. In the current therapeutic landscape, pegylated interferons are recommended for use in the treatment of polycythemia vera, essential thrombocythemia, and primary myelofibrosis. We review recent efficacy, molecular response, and safety data for the two available pegylated interferons, peginterferon alfa-2a (Pegasys) and ropeginterferon alfa-2b-njft (BESREMi). The practical management of interferon-based therapies is discussed, along with our opinions on whether to and how to switch from hydroxyurea to one of these therapies. Key topics and questions related to use of interferons, such as their safety and tolerability, the significance of variant allele frequency, advantages of early treatment, and what the future of interferon therapy may look like, will be examined. Pegylated interferons represent an important therapeutic option for patients with MPNs; however, more research is still required to further refine interferon therapy.

The pharmacotherapeutic management of patients with myelofibrosis: looking beyond JAK inhibitors

INTRODUCTION

The approach to myelofibrosis (MF) has been revolutionized in recent years, overcoming the traditional therapies, often not very effective. Janus kinase inhibitors (JAKi - from ruxolitinib up to momelotinib) were the first class of drugs with considerable results.

AREAS COVERED

Ongoing, new molecules are being tested that promise to give hope even to those patients not eligible for bone marrow transplants who become intolerant or are refractory to JAKi, for which therapeutic hopes are currently limited. Telomerase, murine double minute 2 (MDM2), phosphatidylinositol 3-kinase δ (PI3Kδ), BCL-2/xL, and bromodomain and extra-terminal motif (BET) inhibitors are the drugs with promising results in clinical trials and close to closure with consequent placing on the market, finally allowing JAK to look beyond. The novelty of the MF field was searched in the PubMed database, and the recently completed/ongoing trials are extrapolated from the ClinicalTrial website.

EXPERT OPINION

From this point of view, the use of new molecules widely described in this review, probably in association with JAKi, will represent the future treatment of choice in MF, leaving, in any case, the potential new approaches actually in an early stage of development, such as the use of immunotherapy in targeting CALR, which is coming soon.

Forms and Methods for Interferon's Encapsulation

Interferons (IFNs) are cytokines involved in the immune response that act on innate and adaptive immunity. These proteins are natural cell-signaling glycoproteins expressed in response to viral infections, tumors, and biological inducers and constitute the first line of defense of vertebrates against infectious agents. They have been marketed for more than 30 years with considerable impact on the global therapeutic protein market thanks to their diversity in terms of biological activities. They have been used as single agents or with combination treatment regimens, demonstrating promising clinical results, resulting in 22 different formulations approved by regulatory agencies. The 163 clinical trials with currently active IFNs reinforce their importance as therapeutics for human health. However, their application has presented difficulties due to the molecules' size, sensitivity to degradation, and rapid elimination from the bloodstream. For some years now, work has been underway to obtain new drug delivery systems to provide adequate therapeutic concentrations for these cytokines, decrease their toxicity and prolong their half-life in the circulation. Although different research groups have presented various formulations that encapsulate IFNs, to date, there is no formulation approved for use in humans. The current review exhibits an updated summary of all encapsulation forms presented in the scientific literature for IFN-α, IFN-ß, and IFN-γ, from the year 1996 to the year 2021, considering parameters such as: encapsulating matrix, route of administration, target, advantages, and disadvantages of each formulation.

Interferon alpha therapy in essential thrombocythemia and polycythemia vera-a systematic review and meta-analysis

Data on the efficacy and safety of interferon (IFN)-α for the treatment of essential thrombocythemia (ET) and polycythemia vera (PV) are inconsistent. We conducted a systematic review and meta-analysis and searched MEDLINE and EMBASE via Ovid, Scopus, COCHRANE registry of clinical trials, and Web of Science from inception through 03/2019 for studies of pegylated IFN (peg-IFN) and non-pegylated IFN (non-peg-IFN) in PV and ET patients. Random-effects models were used to pool response rates for the primary outcome of overall response rate (ORR) defined as a composite of complete response, partial response, complete hematologic response (CHR) and partial hematologic response. Peg-IFN and non-peg-IFN were compared by meta-regression analyses. In total, 44 studies with 1359 patients (730 ET, 629 PV) were included. ORR were 80.6% (95% confidence interval: 76.6-84.1%, CHR: 59.0% [51.5%-66.1%]) and 76.7% (67.4-84.0%; CHR: 48.5% [37.8-59.4%]) for ET and PV patients, respectively. In meta-regression analyses results did not differ significantly for non-peg-IFN vs. peg-IFN. Annualized rates of thromboembolic complications and treatment discontinuation due to adverse events were low at 1.2% and 8.8% for ET and 0.5% and 6.5% for PV patients, respectively. Both peg-IFN and non-peg-IFN can be effective and safe long-term treatments for ET and PV.

The clinical role of interferon alpha in Philadelphia-negative myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell malignancies. Chronic inflammation and a dysregulated immune system are central to the pathogenesis and progression of MPNs. Interferon alpha (IFNα) was first used for the treatment of MPNs approximately 40 years ago. It has significant antiviral effects and plays a role in anti-proliferative, pro-apoptotic, and immunomodulatory responses. IFNα is an effective drug that can simultaneously induce significant rates of clinical, hematological, molecular, and histopathological responses, suggesting that the disease may be cured in some patients. However, its frequent dosage and toxicity profile are major barriers to its widespread use. Pegylated IFNα (peg-IFNα), and more recently, ropeginterferon alpha-2b (ropeg-IFNα-2b), are expected to overcome these drawbacks. The objective of this article is to discuss the clinical role of IFNα in Philadelphia-negative MPNs through a review of recent studies. In particular, it is expected that new IFNs, such as peg-IFNα and ropeg-IFNα-2b, with lower rates of discontinuation due to fewer adverse effects, will play important clinical roles.

Repurposing approved drugs for cancer therapy

BACKGROUND

Many drugs approved for other indications can control the growth of tumor cells and limit adverse events (AE).

DATA SOURCES

Literature searches with keywords 'repurposing and cancer' books, websites: https://clinicaltrials.gov/, for drug structures: https://pubchem.ncbi.nlm.nih.gov/.

AREAS OF AGREEMENT

Introducing approved drugs, such as those developed to treat diabetes (Metformin) or inflammation (Thalidomide), identified to have cytostatic activity, can enhance chemotherapy or even replace more cytotoxic drugs. Also, anti-inflammatory compounds, cytokines and inhibitors of proteolysis can be used to control the side effects of chemo- and immuno-therapies or as second-line treatments for tumors resistant to kinase inhibitors (KI). Drugs specifically developed for cancer therapy, such as interferons (IFN), the tyrosine KI abivertinib TKI (tyrosine kinase inhibitor) and interleukin-6 (IL-6) receptor inhibitors, may help control symptoms of Covid-19.

AREAS OF CONTROVERSY

Better knowledge of mechanisms of drug activities is essential for repurposing. Chemotherapies induce ER stress and enhance mutation rates and chromosome alterations, leading to resistance that cannot always be related to mutations in the target gene. Metformin, thalidomide and cytokines (IFN, tumor necrosis factor (TNF), interleukin-2 (IL-2) and others) have pleiomorphic activities, some of which can enhance tumorigenesis. The small and fragile patient pools available for clinical trials can cloud the data on the usefulness of cotreatments.

GROWING POINTS

Better understanding of drug metabolism and mechanisms should aid in repurposing drugs for primary, adjuvant and adjunct treatments.

AREAS TIMELY FOR DEVELOPING RESEARCH

Optimizing drug combinations, reducing cytotoxicity of chemotherapeutics and controlling associated inflammation.

Immunotherapy in Hematologic Malignancies: Emerging Therapies and Novel Approaches

Immunotherapy is extensively investigated for almost all types of hematologic tumors, from preleukemic to relapse/refractory malignancies. Due to the emergence of technologies for target cell characterization, antibody design and manufacturing, as well as genome editing, immunotherapies including gene and cell therapies are becoming increasingly elaborate and diversified. Understanding the tumor immune microenvironment of the target disease is critical, as is reducing toxicity. Although there have been many successes and newly FDA-approved immunotherapies for hematologic malignancies, we have learned that insufficient efficacy due to disease relapse following treatment is one of the key obstacles for developing successful therapeutic regimens. Thus, combination therapies are also being explored. In this review, immunotherapies for each type of hematologic malignancy will be introduced, and novel targets that are under investigation will be described.