Impact of frailty, melphalan pharmacokinetics, and pharmacogenetics on outcomes post autologous hematopoietic cell transplantation for multiple myeloma

Oral and Gut Microbiota Dysbiosis is Associated with Mucositis Severity in Autologous Hematopoietic Stem Cell Transplantation: Evidence from an Asian Population

Mucositis is a debilitating complication of hematopoietic stem cell transplantation (HSCT). It is unclear how changes in the composition of microbiota, which are modulated by geographical location and ethnicity, may influence immune regulation leading to the development of mucositis, and the study of both oral and gut microbiota in a single population of autologous HSCT in the Asian region is lacking. The present study aimed to characterize the oral and gut microbiota changes, and the impact on both oral and lower gastrointestinal (GI) mucositis, with associated temporal changes in a population of adult recipients of autologous HSCT. Autologous HSCT recipients age ≥18 years were recruited from Hospital Ampang, Malaysia, between April 2019 and December 2020. Mucositis assessments were conducted daily, and blood, saliva, and fecal samples were collected prior to conditioning, on day 0, and at 7 days and 6 months post-transplantation. Longitudinal differences in alpha diversity and beta diversity were determined using the Wilcoxon signed-rank test and permutational multivariate analysis of variance, respectively. Changes in relative abundances of bacteria across time points were assessed using the microbiome multivariate analysis by linear models function. The combined longitudinal effects of clinical, inflammatory, and microbiota variables on mucositis severity were measured using the generalized estimating equation. Among the 96 patients analyzed, oral mucositis and diarrhea (representing lower GI mucositis) occurred in 58.3% and 95.8%, respectively. Alpha and beta diversities were significantly different between sample types (P < .001) and across time points, with alpha diversity reaching statistical significance at day 0 in fecal samples (P < .001) and at day +7 in saliva samples (P < .001). Diversities normalized to baseline by 6 months post-transplantation. Significant microbiota, clinical, and immunologic factors were associated with increasing mucositis grades. Increasing relative abundances of saliva Paludibacter, Leuconostoc, and Proteus were associated with higher oral mucositis grades, whereas increasing relative abundances of fecal Rothia and Parabacteroides were associated with higher GI mucositis grades. Meanwhile, increasing relative abundances of saliva Lactococcus and Acidaminococcus and fecal Bifidobacterium were associated with protective effects against worsening oral and GI mucositis grades, respectively. This study provides real-world evidence and insights into the dysbiosis of the microbiota in patients exposed to conditioning regimen during HSCT. Independent of clinical and immunologic factors, we demonstrated significant associations between relative bacteria abundances with the increasing severity of oral and lower GI mucositis. Our findings offer a potential rationale to consider the inclusion of preventive and restorative measures targeting oral and lower GI dysbiosis as interventional strategies to ameliorate mucositis outcome in HSCT recipients.

Characteristics and outcome of infectious complications after autologous hematopoietic cell transplantation in multiple myeloma patients

BACKGROUND

Infections are a significant cause of morbidity and mortality after autologous hematopoietic cell transplantation (AHCT) in multiple myeloma (MM) patients. There has been a rapid advancement and evolution in MM treatment landscape in the last decade. There is limited information on post-AHCT infectious complications among MM patients with or without levofloxacin prophylaxis from developing countries.

MATERIALS AND METHODS

We performed a retrospective study to explore the incidence, pattern, and clinical outcome of infections following AHCT in MM patients from 2010 to 2019 at our center. Patient-specific, disease-specific, and transplant-specific details were retrieved from the case files. The characteristics of infectious complications (site, intensity, organism, treatment, and outcomes) were analyzed. All patients who underwent transplantation from 2010 to 2016 received levofloxacin antibiotic prophylaxis. Common terminology criteria for adverse events (CTCAE) criteria (v5.0) were used for the grading of infections and regimen-related toxicity. International Myeloma Working Group updated criteria were used for the assessment of disease response before transplant and at day +100.

RESULTS

Ninety-five consecutive patients with newly diagnosed multiple myeloma (NDMM) (n = 85), RRMM (n = 7), plasma cell leukemia (n = 2), and Polyneuropathy, Orgaomegaly, Endocrinopathy, Monoclonal gammopathy, skin abnormalities (POEMS) syndrome (n = 1) underwent AHCT during the study period. Their median age was 55 years (range 33-68); 55.8% were males. Immunoglobulin IgG kappa was the most common monoclonal protein (32.6%), International Staging System stage III disease was present in 45.3%, and 84.2% of patients achieved more than very good partial response before AHCT. The median time from diagnosis to AHCT was 10 months (range 4-144). Eighty-nine patients (93.7%) developed fever after AHCT. Fever of unknown focus, microbiologically confirmed infections, and clinically suspected infections were found in 50.5%, 37.9%, and 5.3% of patients, respectively. Clostridiodes difficile-associated diarrhea was observed in eight patients (8.4%). Neutrophil and platelet engraftment occurred after a median of 11 days (range 9-14) and 12 days (range 9-23), respectively. The median duration of hospital stay was 16 days (range 9-29). Only two patients (2.1%) required readmission for infections within 100 days of AHCT. Transplant-related mortality (TRM) in the study population was 4.2% (n = 4). The levofloxacin prophylaxis group (n = 32, 33.7%) had earlier neutrophil engraftment (day +10 vs. day +11) and platelet engraftment (day +11 vs. day +12), but time to fever onset, duration of fever, hospital stay, TRM, and day +100 readmission rates were not significantly different from those of patients without levofloxacin prophylaxis. There was no significant difference in the spectrum of infections between patients with and without levofloxacin prophylaxis. The overall survival and progression-free survival of the study population at 5 years were 72.7% and 64.8%, respectively.

CONCLUSION

This study shows that the incidence of infections and TRM are higher in MM patients from lower-middle income countries after AHCT than in those from developed countries. The majority of such patients lack clinical localization and microbiological proof of infection. There was no significant difference in the spectrum of infections and their outcomes in patients with and without levofloxacin prophylaxis.

Development and validation wise assessment of genotype guided warfarin dosing algorithm in Indian population

OBJECTIVES

A study was conducted to develop and validate the warfarin pharmacogenetic dose optimization algorithm considering the clinical pharmacogenetic implementation consortium (CPIC) recommendations for the Asian ethnicity population.

METHODS

The present prospective observational study recruited warfarin-receiving patients. We collected a three ml blood sample for VKORC1, CYP2C9*2, CYP2C9*3, and CYP4F2 polymorphism assessment during the follow-up visits. Clinical history, sociodemographic and warfarin dose details were noted.

RESULTS

The study recruited 300 patients (250 in derivation and 50 in validation timed cohort) receiving warfarin therapy. The baseline characteristics were similar in both cohorts. BMI, presence of comorbidity, VKORC1, CYP2C9*2, and CYP2C9*3 were identified as covariates significantly affecting the warfarin weekly maintenance dose (p<0.001 for all) and the same were included in warfarin pharmacogenetic dose optimization algorithm building. The algorithm built-in the present study showed a good correlation with Gage (r=0.57, p<0.0001), and IWPC (r=0.51, p<0.0001) algorithms, widely accepted in western side of the globe. The receiver operating characteristic curve analysis showed a sensitivity of 73 %, a positive predictive value of 96 %, and a specificity of 89 %. The algorithm correctly identified the validation cohort's warfarin-sensitive, intermediate reacting, and resistant patient populations.

CONCLUSIONS

Validation and comparisons of the warfarin pharmacogenetic dose optimization algorithm have made it ready for the clinical trial assessment.

Clinical Impact of Melphalan Pharmacokinetics on Transplantation Outcomes in Children Undergoing Hematopoietic Stem Cell Transplantation

Melphalan is widely used for hematopoietic stem cell transplantation (HSCT) conditioning. However, the relationship between its pharmacokinetic (PK) and transplantation outcomes in children has not been thoroughly investigated. We prospectively analyzed the relationship between melphalan area under the curve (AUC) and transplantation outcome and examined the development of a predictive model for melphalan clearance in children. This study included 43 children aged 0 to 19 years who underwent HSCT following a melphalan-based conditioning regimen from 2017 to 2021. In univariable analysis, high-melphalan AUC resulted in a significantly lower cumulative incidence of acute graft-versus-host disease and a higher cumulative incidence of thrombotic microangiopathy, although no significant difference was observed in survival. Regression analysis of a randomly selected derivation cohort (n = 21) revealed the following covariate PK model: predicted melphalan clearance (mL/min) = 6.47 × 24-h urinary creatinine excretion rate (CER, g/day) × 24-h creatinine clearance rate (CCR, mL/min) + 92.8. In the validation cohort (n = 22), the measured melphalan clearance values were significantly correlated with those calculated based on the prediction equation (R² = 0.663). These results indicate that melphalan exposure may be optimized by adjusting the melphalan dose according to CER and CCR.

The Nitrogen Mustards

The nitrogen mustards are powerful cytotoxic and lymphoablative agents and have been used for more than 60 years. They are employed in the treatment of cancers, sarcomas, and hematologic malignancies. Cyclophosphamide, the most versatile of the nitrogen mustards, also has a place in stem cell transplantation and the therapy of autoimmune diseases. Adverse effects caused by the nitrogen mustards on the central nervous system, kidney, heart, bladder, and gonads remain important issues. Advances in analytical techniques have facilitated the investigation of the pharmacokinetics of the nitrogen mustards, especially the oxazaphosphorines, which are prodrugs requiring metabolic activation. Enzymes involved in the metabolism of cyclophosphamide and ifosfamide are very polymorphic, but a greater understanding of the pharmacogenomic influences on their activity has not yet translated into a personalized medicine approach. In addition to damaging DNA, the nitrogen mustards can act through other mechanisms, such as antiangiogenesis and immunomodulation. The immunomodulatory properties of cyclophosphamide are an area of current exploration. In particular, cyclophosphamide decreases the number and activity of regulatory T cells, and the interaction between cyclophosphamide and the intestinal microbiome is now recognized as an important factor. New derivatives of the nitrogen mustards continue to be assessed. Oxazaphosphorine analogs have been synthesized in attempts to both improve efficacy and reduce toxicity, with varying degrees of success. Combinations of the nitrogen mustards with monoclonal antibodies and small-molecule targeted agents are being evaluated. SIGNIFICANCE STATEMENT: The nitrogen mustards are important, well-established therapeutic agents that are used to treat a variety of diseases. Their role is continuing to evolve.

Influence of GSTM1, GSTT1, and GSTP1 genetic polymorphisms on disorders in transplant patients: a systematic review

The glutathione-S-transferase (GST) enzymes are phase II isoenzymes responsible for protection against free radicals and xenobiotics. Since these proteins are described as polymorphic, polymorphisms in genes that encode them may alter enzymatic function and contribute to oxidative stress. In this context, such polymorphisms were already associated with several diseases and multiple therapeutic outcomes. A systematic review was performed to evaluate studies regarding the association between polymorphisms in three genes encoding enzymes of the GST family - GSTM1, GSTT1, and GSTP1 - and disorders in transplant patients. A total of 125 articles on which inclusion and exclusion criteria were applied were identified at PubMed database. Thirty-two studies met the target criteria and were included in the review. The mechanisms by which GST genotypes influence the development of disorders in transplant patients differ by disorder: they may participate in it by decreasing metabolism of drugs administered to patients undergoing transplantation, then exposing them to greater toxicity; by decreasing the repair ability against oxidative stress; or by encoding proteins that may be recognized as foreign, setting of an alloimmune reaction. Although some results are better established - such as GSTM1 null genotype's role in the development of toxicity events in transplant patients - others require further evidences, as GST influence on the development of pulmonary decline and posttransplant diabetes mellitus (PTDM). The importance of investigating these associations lies in a personalized medicine, in which the high-risk genotype patient has its treatment individualized and its care for prophylaxis and surveillance increased, potentially reducing this population's morbimortality.

Chronic Lymphocytic Leukemia: Real-World Data From India

PURPOSE

Chronic lymphocytic leukemia (CLL) is uncommon in India. There are limited studies on CLL from the Indian subcontinent.

METHODS

This was a prospective study (2011-2017) of consecutively diagnosed patients with CLL at a single center. The diagnosis, prognosis, treatment indication, response criteria, and adverse events were recorded as per International Workshop on Chronic Lymphocytic Leukemia guidelines. Biosimilar rituximab dosing (375 mg/m²) was fixed for all cycles. Time to next treatment (TTNT) was defined as the time from front-line treatment initiation to next treatment or death from any cause. Overall survival (OS) was defined as the time from treatment initiation until death from any cause.

RESULTS

A total of 409 patients with CLL were enrolled over the study period. The median follow-up was 32 months (range, 2-135 months). The median age was 61 years, and 31.8% of patients with CLL were ≤ 55 years of age; 43.3% of patients had a cumulative illness rating scale score ≥ 3. Prognostic fluorescence in situ hybridization data were available in 53.3% of patients. Chlorambucil (94/180; 52.2%) and bendamustine + rituximab (BR; 57/180; 31.6%) were the most common regimens used up front. The overall response rates after front-line therapy were 74.4% and 91.2%, respectively. The TTNT was 33 months and not reached, respectively (P = .001). Grade 3/4 neutropenia and infections were seen in 52.6% and 38.5% of patients receiving BR. The median OS was not reached in both regimens (P = .25).

CONCLUSION

Indian patients with CLL are younger in chronological age but have higher morbidity burden. Treatment outcomes with biosimilar fixed-dose BR are comparable to those reported in the literature. Chlorambucil is still a valid option, given the economic burden of the disease and treatment.

New Horizons in the impact of frailty on pharmacokinetics: latest developments

Frail older people have a high prevalence of drug use and are susceptible to adverse drug reactions. The physiological changes of frailty are likely to affect pharmacokinetics and pharmacodynamics. We reviewed the methods and findings of published studies of pharmacokinetics in frailty. Nine studies describing pharmacokinetics and an additional three of pharmacokinetic pathways in frail older people were identified. Most pharmacokinetic studies investigated a single administration of a medication, dose or formulation, in small populations, often with limited representation of males or females, and applied variable definitions of frailty. Pharmacokinetic sampling designs generally utilised saturated sampling followed by analysis based on the trapezoidal rule for area under the curve, with more recent studies using sparser sampling and more sophisticated modelling to obtain individual and population values of all pharmacokinetic parameters. Overall, the pharmacokinetic studies reported only small changes in some parameters for some drugs with frailty, with the most consistent change reduced hepatic clearance in frail older people. Recommendations for future studies of pharmacokinetics in frailty include (i) standard objective definitions of frailty; (ii) larger studies including people with mild, moderate and severe frailty; (iii) population pharmacokinetic modelling to allow sparser sampling and consideration of multiple influences on pharmacokinetics; (iv) physiologically based modelling as the physiology of frailty emerges and (v) longitudinal pharmacokinetic studies of chronic drug therapy from middle to old age and from robust to pre-frail to frail, including pre-clinical studies. These data, accompanied by pharmacodynamics data in frailty, will inform safe, effective prescribing for frail older people.

Development of a method for clinical pharmacokinetic testing to allow for targeted Melphalan dosing in multiple myeloma patients undergoing autologous transplant

AIMS

High dose melphalan (HDM) and autologous stem cell transplant (ASCT) is standard of care for multiple myeloma (MM), but there is significant variability in melphalan exposure (area under the plasma drug concentration-time curve, AUC) when using body surface area-based dosing. Our aim was to establish a method of pharmacokinetic (PK) testing for real-time melphalan dose adjustments.

METHODS

We performed a prospective PK study of melphalan 140 or 200 mg/m2 in MM patients undergoing ASCT. Twenty MM patients were administered HDM on days -2 and - 1, with PK sampling at 8-10 time points. PK testing was performed on day -2 in all patients, and on day -1 in 5 patients.

RESULTS

Less than 20% interpatient variation in the day -2 and - 1 AUC was observed. The day -2 range in AUC (4.95-11.28 mg h/L) confirmed significant interpatient variability. The hypothetical total dose ranged from 133-302 mg/m2 to achieve the total median AUC. A 4-time point AUC (0, 30, 150 and 240 min) highly correlated with the AUC from the 8-time point schedule. A higher AUC correlated with increased risk of febrile neutropenia (P = .05).

CONCLUSION

Here we outline the methods to establish novel melphalan dosing using PK testing in MM patients undergoing ASCT to target a desired melphalan AUC.

Long-term outcomes of innovator versus generic melphalan formulation in autologous hematopoietic cell transplantation for multiple myeloma

BACKGROUND

Most data on autologous hematopoietic cell transplantation (auto-HCT) in myeloma are based on the use of innovator formulation of melphalan. Comparative bioequivalence and efficacy studies of generic melphalan are lacking.

METHODS

In this retrospective study, we report long-term outcomes of auto-HCT in myeloma using innovator (Alkeran, Aspen Pharma; n = 41) and generic melphalan (Alkacel, Celon Labs, India; n = 55) formulations. All consecutive patients at a single center from the period 2011-2018 were included.

RESULTS

The median follow-up in the innovator and generic groups was 61.7 and 32.5 months, respectively. Both groups were matched for age, sex, stage, and myeloma response. There were significantly more patients in the innovator melphalan group who were administered melphalan at a reduced dose at physician discretion (26.8% vs. 3.6%, p = .001). There were significantly more patients with grade 3 or higher mucositis (68.3% vs. 38.1%, p < .0001) and grade 3 or higher diarrhea (85.4% vs. 50.1%, p < .0001) in the innovator group. The median duration of hospital stay was significantly longer in the innovator group (19 days vs. 15.5 days, p < .0001). There were significantly more patients in the generic group who received standard maintenance (94.5% vs. 34.1%, p < .0001). Despite the differences in the melphalan dose and post-transplant strategies, the 4-year progression-free survival and overall survival were not significantly different in the two groups (58% vs. 63%, p = .7, 71% vs. 72%, p = .4, respectively).

CONCLUSION

Long-term efficacy comparison is helpful in the absence of postmarketing bioequivalence studies of generic melphalan.

Predictors of increased melphalan exposure correlate with overall survival, nonrelapse mortality, and toxicities in patients undergoing reduced-intensity allogeneic stem cell transplantation with fludarabine and melphalan

The reduced-intensity conditioning regimen, fludarabine and melphalan 140 mg/m² (FM140), is widely adopted in practice. Pharmacokinetic studies report 10-fold interpatient variability in melphalan exposure. We identified low hemoglobin (Hb) and/or creatinine clearance (CrCl), determinants of melphalan pharmacokinetic, as strong predictors of outcomes after high-dose melphalan and autologous transplant. We hypothesized that these variables could predict for outcomes after FM140. Overall survival was shorter in patients with a lower Hb (113 vs. 2536 days; p = 0.004), due to an increased rate of nonrelapse mortality (NRM) (p = 0.0005). Overall survival was also worse in patients with lower CrCl (75 vs. 317 days; p = 0.003), with a significantly worse nonrelapse mortality (p = 0.0023). In a multivariate analysis, a higher Hb and CrCl predicted for better overall survival (p = 0.017). In patients with a lower Hb, the median duration of hospitalization (p = 0.02) and the mean duration of diarrhea (p = 0.008) were longer. In patients with a lower CrCl, the median duration of hospitalization (p = 0.06) and the mean duration of diarrhea (p = 0.0009) longer, and the rate of infection was higher (p = 0.02). We show for the first time that Hb and CrCl represent important determinants of outcomes after FM140, suggesting that pharmacokinetic-directed dosing may be beneficial in achieving optimal outcomes.