Oral melphalan pharmacokinetics--relation to dose in patients with multiple myeloma

Does Chemotherapy-Induced Gastrointestinal Mucositis Affect the Bioavailability and Efficacy of Anti-Infective Drugs?

Antimicrobial prophylaxis is increasingly being used in patients with hematological malignancies receiving high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT). However, few studies have focused on the potential impact of gastrointestinal mucositis (GI-M), a frequently observed side effect of chemotherapy in patients with cancer that affects the gastrointestinal microenvironment, on drug absorption. In this review, we discuss how chemotherapy leads to an overall loss of mucosal surface area and consequently to uncontrolled transport across the barrier. The barrier function is depending on intestinal luminal pH, intestinal motility, and diet. Another factor contributing to drug absorption is the gut microbiota, as it modulates the bioavailability of orally administrated drugs by altering the gastrointestinal properties. To better understand the complex interplay of factors in GI-M and drug absorption we suggest: (i) the longitudinal characterization of the impact of GI-M severity on drug exposure in patients, (ii) the development of tools to predict drug absorption, and (iii) strategies that allow the support of the gut microbiota. These studies will provide relevant data to better design strategies to reduce the severity and impact of GI-M in patients with cancer.

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.

Clinical pharmacokinetics of oral drugs in the treatment of multiple myeloma

Treatment of myeloma is a long-term treatment mainly based on all-oral combinations of drugs. Because oral drugs have a more complex pharmacokinetics compared with IV treatments, an appropriate knowledge of the factors that may alter their systemic exposure is of particular clinical relevance. Both drug-drug interactions, food-effect, and dose-adaptation in renal and hepatic impairment may influence the systemic drug levels with a potential impact on drug efficacy or safety. Moreover, a better control of drug exposure may improve the side effect profiles of these treatments with a favourable impact on patient compliance. Furthermore, as long-term treatments, these drugs may also alter the systemic exposure of coadministered medications in these rather old patients. The aim of this review was to identify the factors modifying the systemic exposure of oral drugs used in myeloma by focusing on the pharmacokinetic drug-drug interactions and the effects of renal and hepatic impairment and of food impact.

The interaction between oral melphalan and gastric antisecretory drugs: Impact on clinical efficacy and toxicity

The aim of the present study was to clarify whether gastric antisecretory drugs affect the clinical efficacy and toxicity of orally administered melphalan in patients with multiple myeloma. A total of 10 patients receiving bortezomib plus oral melphalan and prednisolone (VMP) therapy between December 2011 and November 2014 were analyzed retrospectively. The patients were divided into a control group (seven patients) and a concomitant group (three patients, who were also administered with gastric antisecretory drugs). The gastric antisecretory drugs included rabeprazole sodium (two patients) and famotidine (one patient). No significant differences between the groups were observed in either the characteristics of the patients or the VMP regimen. The levels of monoclonal protein (M protein) in the control group tended to decrease (with a VMP cycle-dependency), although they were primarily stable in the concomitant group. During the second and third VMP cycles, the levels of M protein were markedly lower in the control group compared with the concomitant group. All the patients in the control group achieved a partial response, whereas those in the concomitant group exhibited stable disease. Hematological toxicity levels were revealed to be comparable between the two groups, whereas gastrointestinal toxicity was more prevalent in the control group. In conclusion, the results of the present study suggested that the clinical efficacy of melphalan may be reduced by the co-administration of gastric antisecretory drugs. This interaction may result in decreased toxicity and clinical efficacy of melphalan.

A case of melphalan sustained accumulation in an 80-year old patient

Case We report the case of melphalan accumulation in an 80-year old female with multiple myeloma. Her initial health status was good except for a moderate chronic renal failure (estimated glomerular filtration rate: 31 ml/min) and anemia. Among other drugs, her usual treatment included trimethoprim/sulfamethoxazole and the patient received melphalan from day 1 to day 4 for multiple myeloma. On day 13, she was admitted in intensive care unit for acute renal failure and severe sepsis with pancytopenia. Usual treatments were stopped. Melphalan blood concentrations were 123.6 ng/ml on day 16 and 87.5 ng/ml on day 17 while cerebrospinal fluid concentration was 173.8 ng/ml on day 25. Patient recovered on day 30. Melphalan accumulation may be explained by substrate competition between sulfamethoxazole and melphalan in metabolism pathway and chronic renal failure. Conclusion close clinical and renal monitoring should be performed in patient receiving melphalan and sulfamethoxazole.

Intravenous injection of bortezomib, melphalan and dexamethasone in refractory and relapsed multiple myeloma

BACKGROUND

A combination of bortezomib (1.3 mg/m(2)), melphalan (5 mg/m(2)), and dexamethasone (40 mg) (BMD), with all three drugs given as a contemporary intravenous administration, was retrospectively evaluated.

PATIENTS AND METHODS

Fifty previously treated (median 2 previous lines) patients with myeloma (33 relapsed and 17 refractory) were assessed. The first 19 patients were treated with a twice-a-week (days 1, 4, 8, 11, 'base' schedule) administration while, in the remaining 31 patients, the three drugs were administered once a week (days 1, 8, 15, 22, 'weekly' schedule).

RESULTS

Side-effects were predictable and manageable, with prominent haematological toxicity, and a better toxic profile in 'weekly' schedule (36% versus 66% in 'base' schedule). The overall response rate was 62%. After median follow-up of 24.5 months (range 2.7-50 months), the median progression-free survival (PFS) was 21.6 with no difference between the two schedules and the median overall survival (OS) was 33.8 months. Independently from the adopted schedule, we found that also in a cohort of relapsed/refractory patients achieving at least partial remission improved PFS (35.2 versus 9 months) and OS (unreached median versus 18 months).

CONCLUSION

Taken together, our observations suggest that BMD is an effective regimen in advanced myeloma patients with acceptable toxicity.

Treatment of bendamustine and prednisone in patients with newly diagnosed multiple myeloma results in superior complete response rate, prolonged time to treatment failure and improved quality of life compared to treatment with melphalan and prednisone--a randomized phase III study of the East German Study Group of Hematology and Oncology (OSHO)

PURPOSE

This randomized phase III study compared bendamustine and prednisone (BP) to standard melphalan and prednisone (MP) treatment in previously untreated patients with multiple Myeloma (MM).

PATIENTS AND METHODS

To be included, patients had to have histologically and cytologically proven stage II with progressive diseases or stage III MM. They were randomly assigned to receive BP (n=68) or MP (n=63). The primary endpoint was the time to treatment failure (TTF). Secondary endpoints included survival, remission rate, toxicity and quality of life.

RESULTS

The overall response rate was 75% in the BP and 70% in the MP group. A significantly higher number of patients treated with BP achieved a complete remission than did patients receiving MP (32 vs. 13%; P=0.007), and the maximum response was achieved more rapidly in patients treated with BP compared to those receiving MP (6.8 vs. 8.7 cycles; P<0.02). TTF and remission duration were significantly longer in the BP group. Patients receiving BP had higher QoL scores and reported pain less frequently than patients receiving MP.

CONCLUSION

BP is superior to MP with respect to complete remission rate, TTF, cycles needed to achieve maximum remission and quality of life and should be considered the new standard in first-line treatment of MM patients not eligible for transplantation.

Current drug therapy for multiple myeloma

Recent years have witnessed tremendous advances in the molecular pathogenesis and management of multiple myeloma. Standard chemotherapy (melphalan and prednisone; MP) has been the mainstay of treatment of multiple myeloma for about 3 decades. However, it is no longer considered the 'gold standard', particularly for those patients who will subsequently undergo intensive chemotherapy with autologous or allogeneic peripheral blood stem cell (PBSC) or bone marrow transplantation (BMT), or for patients with refractory myeloma. A variety of induction combination chemotherapy regimens have been developed, some of which have demonstrated an improved response rate and duration and a superior 5-year survival rate when compared with standard chemotherapy. The early use of high dose chemotherapy with autologous PBSC support or BMT has significantly increased the complete remission rate, and has prolonged event-free sur vival and overall survival. Allogeneic bone marrow or PBSC transplantation may be a good option for selected patients with poor prognostic features. The role of interferon-alpha in multiple myeloma is still inconclusive despite many years of clinical evaluation. The clinical application of chemosensitising agents that can inhibit P-glycoprotein (P-gp) expression and function, and particularly the development of more potent P-gp modulators such as valspodar (PSC 833) and elacridar (GF120918) has made it possible to reverse multidrug resistance in some refractory patients and to enhance the efficacy of chemotherapeutic agents. Immunotherapeutic approaches to purging of autologous bone marrow or PBSC, or as adjuvant therapy for minimal residual disease, show great promise. Finally, a number of new therapies specifically designed to treat many of the complications of multiple myeloma are improving clinical outcomes and quality of life for these patients.

Pharmacokinetics of peptichemio in myeloma patients: release of m-L-sarcolysin in vivo and in vitro

Peptichemio (PTC) is a mixture of six synthetic oligopeptides, each of which contains the alkylating residue m-[di(2-chloroethyl)amino]-L-phenylalanine (L-mSL). The fate of PTC was investigated in eight patients with multiple myeloma after intravenous infusion of the drug. The quantitative analysis of the plasma samples was performed by liquid chromatography with fluorometric detection. L-mSL was rapidly released from the peptides and reached its maximal plasma concentration at the end of the infusion. Its median elimination half-life was 1.73 (range, 0.72-2.41) h. It was possible to follow the concentration of only one of the peptides, L-mSL-L-Arg(NO2)-L-Nval.OEt, during and shortly after the infusion of PTC. The stability of L-mSL and the peptides was studied in buffer solution (pH 7.3), plasma, and blood. The stability of some of the peptides was drastically decreased in blood, the degradation half-lives being only about 1 min. We conclude that L-mSL plays an important role in the mechanism of action of PTC.