Immunostimulatory Effects of Melphalan and Usefulness in Adoptive Cell Therapy with Antitumor CD4+ T Cells

Comparative analysis of reduced toxicity conditioning regimens between fludarabine plus melphalan and fludarabine plus busulfex in adult patients with acute lymphoblastic leukemia

Reduced-toxicity conditioning (RTC) regimens aim to mitigate regimen-related toxicity while maintaining anti-leukemic efficacy in allogeneic hematopoietic stem cell transplantation (allo-HSCT). We assessed outcomes of RTC regimens utilizing melphalan versus intravenous busulfan combined with fludarabine in adult acute lymphoblastic leukemia (ALL) patients. A retrospective analysis was conducted with 149 consecutive adult ALL patients (median age 51, range 18-60) in remission undergoing allo-HSCT. Patients received either fludarabine 150 mg/BSA plus 2 days of melphalan 70 mg/BSA (FM140, n = 76) from 2009 to 2015 or fludarabine plus 3 days of busulfan 3.2 mg/kg (FB9.6, n = 73) from 2016 to 2021. At 5 years post-HSCT, FM140 demonstrated superior disease-free survival (53.4% vs. 30.5%, p = 0.007) and lower cumulative relapse (27.4% vs. 46.8%, p = 0.026) than FB9.6. Five-year overall survival and non-relapse mortality did not significantly differ. FM140 exhibited a higher incidence of acute graft-versus-host disease (GVHD) grades II-IV (49.3% vs. 30.3%, p = 0.016), though rates of acute GVHD grades III-IV and chronic GVHD were similar. Multivariate analysis identified Philadelphia chromosome and minimal residual disease positive status, and FB9.6 conditioning as predictors of increased relapse and poorer disease-free survival. FM140 RTC regimen displayed significantly reduced relapse and superior disease-free survival compared to FB9.6 in ALL patients undergoing allo-HSCT, highlighting its current clinical utility.

Strategic infection prevention after genetically modified hematopoietic stem cell therapies: recommendations from the International Society for Cell & Gene Therapy Stem Cell Engineering Committee

There is lack of guidance for immune monitoring and infection prevention after administration of ex vivo genetically modified hematopoietic stem cell therapies (GMHSCT). We reviewed current infection prevention practices as reported by providers experienced with GMHSCTs across North America and Europe, and assessed potential immunologic compromise associated with the therapeutic process of GMHSCTs described to date. Based on these assessments, and with consensus from members of the International Society for Cell & Gene Therapy (ISCT) Stem Cell Engineering Committee, we propose risk-adapted recommendations for immune monitoring, infection surveillance and prophylaxis, and revaccination after receipt of GMHSCTs. Disease-specific and GMHSCT-specific considerations should guide decision making for each therapy.

Design, synthesis and biological evaluation of novel cationic liposomes loaded with melphalan for the treatment of cancer

Therapeutically active lipids in drug delivery systems offer customization for enhanced pharmaceutical and biological effects, improving safety and efficacy. Biologically active N, N-didodecyl-3,4-dimethoxy-N-methylbenzenaminium lipid (Q) was synthesized and employed to create a liposome formulation (FQ) encapsulating melphalan (M) through a thin film hydration method. Synthesized cationic lipids and their liposomal formulation underwent characterization and assessment for additive anti-cancer effects on myeloma and melanoma cancer cell lines. These effects were evaluated through various studies, including cytotoxicity assessments, cell cycle arrest analysis, apoptosis measurements, mitochondrial membrane potential depolarization, DNA fragmentation, and a significant reduction in tumorigenic potential, as evidenced by a decrease in both the number and percentage area of cancer spheroids.

The Diagnosis and Management of Cutaneous Metastases from Melanoma

Melanoma is one of the deadliest skin tumors, accounting for almost 90% of skin cancer mortality. Although immune therapy and targeted therapy have dramatically changed the prognosis of metastatic melanoma, many patients experience disease progression despite the currently available new treatments. Skin metastases from melanoma represent a relatively common event as first sign of advanced disease or a sign of recurrence. Skin metastases are usually asymptomatic, although in advanced stages, they can present with ulceration, bleeding, and superinfection; furthermore, they can cause symptoms related to compression on nearby tissues. Treatments vary from simple surgery resections to topical or intralesional local injections, or a combination of these techniques with the most recent systemic immune or target therapies. New research and studies should focus on the pathogenesis and molecular mechanisms of the cutaneous metastases of melanoma in order to shed light on the mechanisms underlying the different behavior and prognoses of different patients.

Establishing the applicability of cancer vaccines in combination with chemotherapeutic entities: current aspect and achievable prospects

Cancer immunotherapy is one of the recently developed cancer treatment modalities. When compared with conventional anticancer drug regimens, immunotherapy has shown significantly better outcomes in terms of quality of life and overall survival. It incorporates a wide range of immunomodulatory modalities that channel the effects of the immune system either by broadly modulating the host immune system or by accurately targeting distinct tumor antigens. One such treatment modality that has gained interest is cancer vaccine therapy which acts by developing antibodies against tumor cells. Cancer vaccines target individual peptides or groups of antigens that are released by tumor cells and presented by the APCs. This also initiates an effective process to activate the host immune responses. Studies on various types of cancer vaccines are conducted, out of which only few are approved by FDA for clinical uses. Despite of documented safety and efficacy of conventional chemotherapy and cancer vaccines, individually they did not produce substantial results in eradication of the cancer as a monotherapy. Hence, the combination approach holds the extensive potential to provide significant improvement in disease outcomes. Certain chemotherapy has immunomodulatory effects and is proven to synergize with cancer vaccines thereby enhancing their anti-tumor activities. Chemotherapeutic agents are known to have immunostimulatory mechanisms apart from its cytotoxic effect and intensify the anti-tumor activities of vaccines by various mechanisms. This review highlights various cancer vaccines, their mechanism, and how their activity gets affected by chemotherapeutic agents. It also aims at summarizing the evidence-based outcome of the combination approach of a cancer vaccine with chemotherapy and a brief on future aspects.

DFT study of therapeutic potential of graphitic carbon nitride as a carrier for controlled release of melphalan: an anticancer drug

In the present research, the drug-delivery efficiency of graphitic carbon nitride (g-CN) for melphalan (an anti-cancer drug) was evaluated. To investigate the efficacy of g-CN as a drug-delivery system, the electronic properties of melphalan drug, g-CN, and g-CN-melphalan were calculated at the ground and excited states. The adsorption energy calculated for g-CN-melphalan complex in the water phase is - 1.51 eV. The interactions between g-CN and melphalan were investigated by a non-covalent interactions (NCl) analysis, which showed that there were weak interactions between g-CN and melphalan drug. These low intermolecular forces will allow for easy off-loading of the melphalan at the targeted site. Frontier molecular-orbitals (FMOs) analysis showed that the charge was transferred from melphalan to g-CN during the excitation process. Charge transfer was studied by charge decomposition analysis. Calculations at the excited state revealed that the g-CN-melphalan complex's λ_max showed a redshift of 15 nm and 39 nm in the gas and water phase, respectively. The photoinduced electron transfer (PET) process was studied for 1-2 excited state by using electron hole theory. PET process suggests that fluorescence quenching may take place. The findings demonstrated that g-CN can be used as a drug-delivery system for melphalan drug to treat cancer. This investigation may also encourage more consideration of different 2D substances for drug delivery.

Vitamin E Oil Incorporated Liposomal Melphalan and Simvastatin: Approach to Obtain Improved Physicochemical Characteristics of Hydrolysable Melphalan and Anticancer Activity in Combination with Simvastatin Against Multiple Myeloma

The objective of this research was to develop vitamin E oil (VEO)-loaded liposomes for intravenous delivery and to study the VEO effect on melphalan (MLN) loading, release, and stability. Further, the research aim was to determine the in vitro anticancer activity and in vivo systemic toxicity of MLN and simvastatin (SVN) combinations, for repurposing SVN in multiple myeloma. The liposomes were prepared by thin-film hydration technique. The optimized liposomes were surface modified with Pluronic F108, lyophilized, and evaluated for mean particle size, MLN content and release behavior, and in vitro hemolysis, cytotoxicity, and macrophage uptake characteristics. Further, in vivo acute toxicity of plain MLN + SVN combination was determined in comparison to their liposomal combination. The VEO alone and in combination with D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) has significantly increased the MLN and SVN loading. The reconstituted liposomes showed the mean particle size below 200 nm (cryo-transmission electron microscope analysis also revealed the liposome formation). In presence of VEO, the liposomes have shown substantially controlled drug release, lower hemolysis, sustained cytotoxicity, lower phagocytosis, and moderately improved chemical stability. Besides, the effect of liposomal combination on mice bodyweight is found substantially lower than the plain drug combination. In conclusion, the VEO could be used along with phospholipids and cholesterol to develop liposomal drugs with improved physicochemical characteristics. Further, the interesting cytotoxicity study results indicated that SVN could be repurposed in combination with anticancer drug MLN against multiple myeloma; liposomal drugs could be preferred to obtain improved efficacy with decreased systemic toxicity.

Metabolic Changes Are Associated with Melphalan Resistance in Multiple Myeloma

Multiple myeloma is an incurable hematological malignancy that impacts tens of thousands of people every year in the United States. Treatment for eligible patients involves induction, consolidation with stem cell rescue, and maintenance. High-dose therapy with a DNA alkylating agent, melphalan, remains the primary drug for consolidation therapy in conjunction with autologous stem-cell transplantation; as such, melphalan resistance remains a relevant clinical challenge. Here, we describe a proteometabolomic approach to examine mechanisms of acquired melphalan resistance in two cell line models. Drug metabolism, steady-state metabolomics, activity-based protein profiling (ABPP, data available at PRIDE: PXD019725), acute-treatment metabolomics, and western blot analyses have allowed us to further elucidate metabolic processes associated with melphalan resistance. Proteometabolomic data indicate that drug-resistant cells have higher levels of pentose phosphate pathway metabolites. Purine, pyrimidine, and glutathione metabolisms were commonly altered, and cell-line-specific changes in metabolite levels were observed, which could be linked to the differences in steady-state metabolism of naïve cells. Inhibition of selected enzymes in purine synthesis and pentose phosphate pathways was evaluated to determine their potential to improve melphalan's efficacy. The clinical relevance of these proteometabolomic leads was confirmed by comparison of tumor cell transcriptomes from newly diagnosed MM patients and patients with relapsed disease after treatment with high-dose melphalan and autologous stem-cell transplantation. The observation of common and cell-line-specific changes in metabolite levels suggests that omic approaches will be needed to fully examine melphalan resistance in patient specimens and define personalized strategies to optimize the use of high-dose melphalan.

Treatment of Multiple Myeloma and the Role of Melphalan in the Era of Modern Therapies-Current Research and Clinical Approaches

Multiple myeloma (MM) accounts for 10% of all hematological malignancies, and it is the second most common hematological neoplasm for which chemotherapy is an important pharmacological treatment. High dose melphalan followed by autologous stem cell transplantation remains the standard of treatment for transplant-eligible patients with MM. In this review, we describe aspects of the pharmacokinetics and pharmacodynamics of melphalan therapy and related compounds. In addition, we describe the use of melphalan in innovative therapies for the treatment of MM, including the development of drug carriers to reduce systemic toxicity, combination therapy to improve the effectiveness of cancer therapy, and the chemical modification of the melphalan molecule to improve antitumor activity.

The role for intra-arterial chemotherapy for refractory retinoblastoma: a systematic review

BACKGROUND

Intra-arterial chemotherapy is a new retinoblastoma treatment associated with high rates of globe salvage that has been widely adopted for primary treatment of retinoblastoma but is less frequently used as secondary treatment for refractory retinoblastoma. This systematic review aims to summarize the reported outcomes of intra-arterial chemotherapy for refractory retinoblastoma.

METHODS

We conducted a systematic review of studies published on PubMed, Medline, and Embase from 2011 to 2021 reporting globe salvage rates following intra-arterial chemotherapy for secondary treatment of refractory retinoblastoma.

RESULTS

Our search yielded 316 studies, and 24 met inclusion criteria. The 24 included studies were comprised of 1366 patients and 1757 eyes. Among these, 1184 (67%) eyes received secondary indication treatment, and globe salvage was achieved for 776 of these 1184 eyes (64%). Sixteen studies reported cannulation success rates from 71.8 to 100%. Pooled analysis of subjects revealed 21 patients (2.6%) with metastatic disease and 26 deaths (3%) during study follow-up periods (7-74 months). The most common ocular complications were vitreous hemorrhage (13.2%), loss of eyelashes (12.7%), and periocular edema (10.5%). The most common systemic complications were nausea/vomiting (20.5%), neutropenia (14.1%), fever (8.2%), and bronchospasm (6.2%).

CONCLUSIONS

Intra-arterial chemotherapy is associated with high rates of globe salvage and low rates of serious complications in patients with refractory retinoblastoma. Unfortunately, current literature is predominantly comprised of retrospective case studies, and further high-quality evidence is necessary to inform clinical practice.

Gut Bacteria of Columbia livia Are a Potential Source of Anti-Tumour Molecules

Objectives:

The overall aim was to determine whether gut bacteria of Columbia livia are a potential source of antitumour molecules.

Methods:

Faecal and gut microbiota of Columbia livia were isolated, identified and conditioned media were prepared containing metabolites. Growth inhibition, lactate dehydrogenase cytotoxicity and cell survival assays were accomplished against cervical cancer cells. Next, liquid-chromatography mass spectrometry was conducted to elucidate the molecules present.

Results:

A plethora of bacteria from faecal matter and gastrointestinal tract were isolated. Selected conditioned media exhibited potent anticancer effects and displayed cytotoxicity to cervical cancer cells at IC₅₀ concentration of 10.65 and 15.19 µg/ml. Moreover, cells treated with conditioned media exhibited morphological changes, including cell shrinking and rounding; indicative of apoptosis, when compared to untreated cells. A total of 111 and 71 molecules were revealed from these gut and faecal metabolites. The identity of 60 molecules were revealed including, dihydroxymelphalan. Nonetheless, 122 molecules remain unidentified and are the subject of future studies.

Conclusion:

These findings suggest that gut bacteria of Columbia livia possess molecules, which may have anticancer activities. Further in silico testing and/or high throughput screening will determine potential anticancer properties of these molecules.

Molecular Aspects of the Isolated Limb Infusion Procedure

For decades, isolated limb infusion (ILI) and hyperthermic isolated limb perfusion (HILP) have been used to treat melanoma in-transit metastases and unresectable sarcoma confined to the limb utilizing the effect of loco-regional high-dose chemotherapy to the isolated limb. Both procedures are able to provide high response rates in patients with numerous or bulky lesions in whom other loco-regional treatments are becoming ineffective. In comparison to systemic therapies, on the other hand, ILI and HILP have the advantage of not being associated with systemic side-effects. Although in principle ILI and HILP are similar procedures, ILI is technically simpler to perform and differs from HILP in that it takes advantage of the hypoxic and acidotic environment that develops in the isolated limb, potentiating anti-tumour activity of the cytotoxic agents melphalan +/− actinomycin-D. Due to its simplicity, ILI can be used in both preclinical and clinical studies to test new cytotoxic regimens and combinations with the aim to overcome tumour resistance. In the future, administration of cytotoxic agents by ILI, in combination with systemic treatments such as BRAF/MEK/KIT inhibitors, immunotherapy (CTLA-4 blockade), and/or programmed death (PD-1) pathway inhibitors, has the potential to improve responses further by inducing increased tumour cell death while limiting the ability of the tumour to suppress the immune response.

Belantamab Mafodotin to Treat Multiple Myeloma: A Comprehensive Review of Disease, Drug Efficacy and Side Effects

Multiple myeloma (MM) is a hematologic malignancy characterized by excessive clonal proliferation of plasma cells. The treatment of multiple myeloma presents a variety of unique challenges due to the complex molecular pathophysiology and incurable status of the disease at this time. Given that MM is the second most common blood cancer with a characteristic and unavoidable relapse/refractory state during the course of the disease, the development of new therapeutic modalities is crucial. Belantamab mafodotin (belamaf, GSK2857916) is a first-in-class therapeutic, indicated for patients who have previously attempted four other treatments, including an anti-CD38 monoclonal antibody, a proteosome inhibitor, and an immunomodulatory agent. In November 2017, the FDA designated belamaf as a breakthrough therapy for heavily pretreated patients with relapsed/refractory multiple myeloma. In August 2020, the FDA granted accelerated approval as a monotherapy for relapsed or treatment-refractory multiple myeloma. The drug was also approved in the EU for this indication in late August 2020. Of note, belamaf is associated with the following adverse events: decreased platelets, corneal disease, decreased or blurred vision, anemia, infusion-related reactions, pyrexia, and fetal risk, among others. Further studies are necessary to evaluate efficacy in comparison to other standard treatment modalities and as future drugs in this class are developed.

A new parameter in multiple myeloma: CYP3A4*1B single nucleotide polymorphism

Multiple myeloma (MM) is a disease caused by malignant plasma cells, causing free light chain release accompanying the increase in monoclonal immunoglobulin. Cytochrome P450 (CYP) is one of the large and functional enzyme families composed of various hemoproteins. This protein network has been shown to play a role in many treatment steps in current practices. We aimed to investigate the relationship between genotypes of CYP3A4*1B and treatment response and prognosis of MM. Seventy-two patients diagnosed with MM between January 2016 and 2020 and 100 healthy people to create a control group participated in our study. Genotypes were classified in 3 separate groups as NN, MN, and MM. Both PFS and OS were significantly higher in the NN genotype (p = 0.001, p = 0.014). Being under the age of 65 was 27.988 times more protective for OS and 4.496 times for PFS (p = 0.006, p = 0.017). NN genotype was shown to be 41.666-fold protective for OS and 3.144-fold protective for PFS (p = 0.004, p = 0.030). This study demonstrated that CYP3A4*1B NN genotype, which is an important cytochrome p450 member for the treatment of MM, was 41.666-fold protective for OS and 3.144-fold protective for PFS. It was shown in this study for the first time in the literature as a valuable contribution.

Continuous lenalidomide and low-dose dexamethasone in patients with transplant-ineligible newly diagnosed MM: FIRST trial subanalysis of Canadian/US patients

The phase 3 FIRST trial demonstrated significant improvement in progression-free survival (PFS) and overall survival (OS) with an immune-stimulatory agent, lenalidomide, in combination with low-dose dexamethasone until disease progression (Rd continuous) vs melphalan +prednisone + thalidomide (MPT) in transplant-ineligible patients with newly diagnosed multiple myeloma (NDMM). Rd continuous similarly extended PFS vs fixed-duration Rd for 18 cycles (Rd18). Outcomes in the Canadian/US subgroup (104 patients per arm) are reported in this analysis. Rd continuous demonstrated a significant improvement in PFS vs MPT (median, 29.3 vs 20.2 months; HR, 0.69 [95% CI, 0.49-0.97]; p = 0.03326) and an improvement vs Rd18 (median, 21.9 months). Median OS was 56.9 vs 46.8 months with Rd continuous vs MPT (p = 0.15346) and 59.5 months with Rd18. The overall response rate was higher with Rd continuous and Rd18 (78.8% and 79.8%) vs MPT (65.4%). In the 49.0%, 52.9%, and 29.8% of patients with at least very good partial response in the Rd continuous, Rd18, and MPT arms, respectively, the median PFS was 56.0, 30.9, and 40.2 months, respectively. The most common grade 3/4 treatment-emergent adverse events were neutropenia (28.4%, 30.1%, and 52.0%), anemia (23.5%, 21.4%, and 23.5%), and infections (37.3%, 30.1%, and 24.5%) with Rd continuous, Rd18, and MPT, respectively. These results were consistent with those in the intent-to-treat population, confirming the benefit of Rd continuous vs MPT in the Canadian/US subgroup and supporting the role of Rd continuous as a standard of care for transplant-ineligible patients with NDMM.

High mobility group box 1 (HMGB1): a pivotal regulator of hematopoietic malignancies

High mobility group box 1 (HMGB1) is a nonhistone chromatin-associated protein that has been widely reported to play a pivotal role in the pathogenesis of hematopoietic malignancies. As a representative damage-associated molecular pattern (DAMP), HMGB1 normally exists inside cells but can be secreted into the extracellular environment through passive or active release. Extracellular HMGB1 binds with several different receptors and interactors to mediate the proliferation, differentiation, mobilization, and senescence of hematopoietic stem cells (HSCs). HMGB1 is also involved in the formation of the inflammatory bone marrow (BM) microenvironment by activating proinflammatory signaling pathways. Moreover, HMGB1-dependent autophagy induces chemotherapy resistance in leukemia and multiple myeloma. In this review, we systematically summarize the emerging roles of HMGB1 in carcinogenesis, progression, prognosis, and potential clinical applications in different hematopoietic malignancies. In summary, targeting the regulation of HMGB1 activity in HSCs and the BM microenvironment is highly beneficial in the diagnosis and treatment of various hematopoietic malignancies.

Coincident remission of ankylosing spondylitis after autologous stem cell transplantation for multiple myeloma

INTRODUCTION

Ankylosing spondylitis is an autoimmune disease with chronic inflammation of the spine and sacroiliac joints that is commonly treated with immunosuppressants including disease-modifying antirheumatic drugs and anti-tumor necrosis factor alpha therapy.

CASE REPORT

A 75-year-old female with active ankylosing spondylitis on treatment with etanercept was referred to us for newly diagnosed IgG kappa free light chain multiple myeloma. After failing induction with revlimid, bortezomib, and dexamethasone, she was initiated on carfilzomib. Following the achievement of adequate response to induction, she underwent an autologous hematopoietic stem cell transplant selected for CD34+ cells with melphalan 200mg/m² conditioning regimen. Given high-risk cytogenetics, i.e. monosomy 17 (17p) and hypodiploidy, she received two cycles of carfilzomib consolidation post-transplant. The patient tolerated the transplant well with successful engraftment and achieved complete remission of multiple myeloma with no detectable M spike, negative immunofixation study, and normalization of light chain ratio. While being off etanercept since the transplant, she noticed complete relief from joint pains related to her ankylosing spondylitis without a need to use the pain-relieving medications.Management and outcome: The patient has sustained remission of ankylosing spondylitis for two years post-transplant without flares or symptoms. She continues to remain off immunosuppressants.

DISCUSSION

Although our patient had a coincident and unprecedented resolution of ankylosing spondylitis after receiving the hematopoietic stem cell transplant, this case consolidates the idea of transplant as a potential treatment option for ankylosing spondylitis and other rheumatological conditions.

Synthesis, Characterization, and In Vitro Studies of an Reactive Oxygen Species (ROS)-Responsive Methoxy Polyethylene Glycol-Thioketal-Melphalan Prodrug for Glioblastoma Treatment

Glioblastoma (GBM) is the most frequent and aggressive primary tumor of the brain and averages a life expectancy in diagnosed patients of only 15 months. Hence, more effective therapies against this malignancy are urgently needed. Several diseases, including cancer, are featured by high levels of reactive oxygen species (ROS), which are possible GBM hallmarks to target or benefit from. Therefore, the covalent linkage of drugs to ROS-responsive molecules can be exploited aiming for a selective drug release within relevant pathological environments. In this work, we designed a new ROS-responsive prodrug by using Melphalan (MPH) covalently coupled with methoxy polyethylene glycol (mPEG) through a ROS-cleavable group thioketal (TK), demonstrating the capacity to self-assembly into nanosized micelles. Full chemical-physical characterization was conducted on the polymeric-prodrug and proper controls, along with in vitro cytotoxicity assayed on different GBM cell lines and “healthy” astrocyte cells confirming the absence of any cytotoxicity of the prodrug on healthy cells (i.e. astrocytes). These results were compared with the non-ROS responsive counterpart, underlining the anti-tumoral activity of ROS-responsive compared to the non-ROS-responsive prodrug on GBM cells expressing high levels of ROS. On the other hand, the combination treatment with this ROS-responsive prodrug and X-ray irradiation on human GBM cells resulted in an increase of the antitumoral effect, and this might be connected to radiotherapy. Hence, these results represent a starting point for a rationale design of innovative and tailored ROS-responsive prodrugs to be used in GBM therapy and in combination with radiotherapy.

Chemical modification of melphalan as a key to improving treatment of haematological malignancies

Chemical modification of known, effective drugs is one method to improve chemotherapy. Thus, the object of this study was to generate melphalan derivatives with improved cytotoxic activity in human cancer cells (RPMI8226, HL60 and THP1). Several melphalan derivatives were synthesised, modified in their two important functional groups. Nine analogues were tested, including melphalan compounds modified: only at the amino group, by replacing the amine with an amidine group containing a morpholine ring (MOR-MEL) or with an amidino group and dipropyl chain (DIPR-MEL); only at the carboxyl group to form methyl and ethyl esters of melphalan (EM-MEL, EE-MEL); and in a similar manner at both functional groups (EM-MOR-MEL, EE-MOR-MEL, EM-DIPR-MEL, EE-DIPR-MEL). Melphalan derivatives were evaluated for cytotoxicity (resazurin viability assay), genotoxicity (comet assay) and the ability to induce apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labelling, TUNEL, phosphatidylserine externalisation, chromatin condensation, activity of caspases 3/7, 8 and 9 and intracellular concentration of calcium ions) in comparison with the parent drug. Almost all derivatives, with the exception of MOR-MEL and DIPR-MEL, were found to be more toxic than melphalan in all cell lines evaluated. Treatment of cultures with the derivatives generated a significant higher level of DNA breaks compared to those treated with melphalan, especially after longer incubation times. In addition, all the melphalan derivatives demonstrated a high apoptosis-inducing ability in acute monocytic and promyelocytic leukemia cells. This study showed that the mechanism of action of the tested compounds differed depending on the cell line, and allowed the selection of the most active compounds for further, more detailed investigations.