Sweet's syndrome and myelodysplasia: two entities with a common pathogenetic mechanism? A case report.
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Acute Disease↗
Biomedical subjects
A Corso
Publications and source records attributed to A Corso.
Assessment of renal function in patients with multiple myeloma: the role of urinary proteins.
Renal failure (RF) in multiple myeloma (MM) is considered an ominous complication even though, when timely therapy is started in patients with minimal damage, a high percentage of cases can achieve a regression. The evaluation of renal involvement usually relies on serum creatinine or its clearance, but these parameters have proved to be inadequate to identify initial damage. The aim of this study was to assess the role of the following urinary proteins in diagnosing renal impairment at an early stage: high-molecular-mass proteins (transferrin, IgG, albumin) as markers of glomerular damage, and low-molecular-weight proteins and parenchymal enzymes [alpha(1)-acid glycoprotein (AGP), alpha(1)-microglobulin (alpha(1)M), retinol-binding protein (RBP), beta(2)-microglobulin (beta(2)M), lysozyme (LZ), and N-acetyl-beta-d-glucosaminidase (NAG)] as indicators of tubular disorder. Thirty MM patients (nine at disease onset and 21 previously treated) were included in the study. No correlation was found between the urinary proteins and the phase or the stage of the disease. By the Spearman test, Bence Jones proteinuria correlated significantly with the 24 h proteinuria (p=0. 01) and beta(2)M (p=0.02), and weakly with the alpha(1)M. Serum creatinine concentrations and urea correlated with most of the analytes evaluated: RBP correlated well with urea (p=0.004) and creatinine (p=0.004); IgG (p=0.006) albumin (p=0.009), AGP (p=0.04), and NAG (p=0.02) correlated with serum creatinine. Significant statistical correlation was found between all the analytes except LZ and the creatinine clearance. Twelve of the 30 MM patients (40%) showed abnormal values of urinary proteins. Four of these patients showed overt renal failure with significant modification of the serum parameters and of creatinine clearance, three showed an isolated decrease of creatinine clearance, and five did not present any alteration of serum or urinary parameters. This testifies to the utility of urinary proteins in highlighting renal damage even in cases where the customary serum indicators of renal disorder are normal. In conclusion, our results demonstrate that AGP, RBP, NAG, transferrin, and IgG are good indicators of renal damage. They do not correlate with the severity of the disease, but they seem to be helpful in identifying a subset of patients with initial renal dysfunction.
Adult↗
Fludarabine, cyclophosphamide, and dexamethasone (FluCyD) combination is effective in pretreated low-grade non-Hodgkin's lymphoma.
PURPOSE: Fludarabine phosphate is effective as a single agent in low-grade non-Hodgkin's lymphoma (NHL). Combined with other antineoplastic agents it enhances the antitumor effect. Our aim was to define the therapeutic efficacy and toxicity of a combination of fludarabine, cyclophosphamide and dexamethasone (FluCyD) in patients with advanced low-grade lymphoma. PATIENTS AND METHODS: Twenty-five adults with pretreated advanced-stage low-grade NHL were treated with three-day courses of fludarabine 25 mg/m2/day, cyclophosphamide 350 mg/m2/day, and dexamethasone 20 mg/day, every four weeks for a maximum of six courses. RESULTS: Of the 25 patients, 18 (72%) responded, 8 (32%) achieving CR and 10 (40%) PR. Seven were failures. The median follow-up was 21 months (5-26). Eight CR patients remain in CR after 5-21 months. Of 10 PR patients, 3 are in continuous PR without further treatment after 12, 17 and 18 months. Myelosuppression was the most prevalent toxic effect. Although severe granulocytopenia (granulocyte count nadir < 500/microliter) and thrombocytopenia (platelet count nadir < 50,000/microliter) occurred in only 10% and 16% of courses, respectively, slow granulocyte or platelet count recovery caused delay of 40% of the courses. Nine patients (36%) required discontinuation of therapy because of persistent granulocytopenia and/or thrombocytopenia: three after one course, three after 2-4 courses, and three after five courses. Thirteen infectious episodes in 11 patients complicated 11% of courses. Two of 10 patients monitored for the circulating EBV load showed increased viral load. One of these developed aggressive lymphoma. CD4+ lymphocytes declined from a pre-therapy median value of 425/microliter to 141/microliter post-treatment (P = 0.001). Non-hematologic toxicities were rare and mild. CONCLUSIONS: The combination of fludarabine with cyclophosphamide and dexamethasone is effective in pretreated advanced-stage low-grade NHL. It may broaden the range of therapeutic options in the salvage treatment of these patients. The main toxicity of this combination is prolonged myelosuppression that may cause treatment delay or withdrawal. The benefit of adding granulocyte colony-stimulating factor, particularly in patients with poor marrow reserve, needs to be investigated.
Adult↗
A successful combination of plasma exchange and intravenous cyclophosphamide in a patient with a refractory thrombotic thrombocytopenic purpura.
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Combined Modality Therapy↗
[Monitoring antibiotic resistance in Argentina. The WHONET program, 1995-1996].
The World Health Organization has implemented a surveillance program for antimicrobial resistance that is known as WHONET. In Argentina the program was developed through a network of 23 public and private hospitals that participate in national and international quality-control programs. Between January 1995 and December 1996, the antimicrobial susceptibility of 16,073 consecutive clinical isolates was determined, using the recommended standards of the National Committee for Clinical Laboratory Standards of the United States of America. More than half of the Escherichia coli urinary isolates were resistant to ampicillin and more than 30% to trimethoprim/sulfamethoxazole (SXT). When the percentage of resistant isolates from outpatients (OPs) was compared to that observed in hospitalized patients (HPs), a marked difference in antimicrobial activity was noted in the case of gentamicin (2% from OPs resistant vs. 8% from HPs resistant), norfloxacin (2% vs. 6%), and third-generation cephalosporins (7% vs. 15%). Of the Klebsiella pneumoniae isolates recovered from blood cultures, 71% and 60% showed resistance to third-generation cephalosporins and to gentamicin, respectively. The overall rate of oxacillin resistance in Staphylococcus aureus was 39%. Around half of the Enterococcus spp. isolates showed high resistance to aminoglycosides, but resistance to glycopeptides was not found. In Argentina, ampicillin and SXT were not suitable for treating diarrhea. Shigella flexneri had a higher number of isolates resistant to both of those drugs (87% and 74%, respectively) than Sh. sonnei did (47% and 71%, respectively). About 40% of the Salmonella spp. isolated in pediatric hospitals were resistant to third-generation cephalosporins. When microorganisms causing bacterial meningitis were examined, Streptococcus pneumoniae showed a resistance rate of 18% to penicillin and Haemophilus influenzae a resistance rate of 19% to ampicillin. These rates are within the intermediate range reported for other countries of the Americas and for Europe.
Cephalosporins↗
Plateau phase in multiple myeloma: an end-point of conventional-dose chemotherapy.
BACKGROUND AND OBJECTIVE: In multiple myeloma (MM) patients treated with conventional chemotherapy, the attainment and duration of a plateau phase seems to affect survival more than the degree of response to initial treatment. The aims of this study are: 1) to analyze within a cohort of previously untreated MM patients the incidence and the duration of the plateau phase; 2) to correlate it with the presenting features; 3) to assess its impact on survival. DESIGN AND METHODS: A series of 146 consecutive MM patients treated with conventional chemotherapy were evaluated for this study. Of 146 patients, 102 responded (13 achieving complete response, 21 partial response, and 68 minimal response), and 44 showed less than minimal response or a progression. A plateau phase was documented in 115 patients (comprising all responders and 13 non responders. The median plateau phase duration was 21.6 months. The majority of patients received intermittent cycles of chemotherapy (melphalan or interferon) during the plateau phase. In multivariate analysis, lytic lesions, response, and time to the best response (TBR) correlated with the attainment of a plateau, while stage, response as a whole, and TBR showed a significant correlation with the duration. In contrast, the type of response did not correlate with either the attainment or the duration of plateau. To analyze the prognostic impact of presenting features, response to therapy and plateau we used a hierarchical model for survival. The analysis showed that the response to therapy and the duration of plateau significantly affect the survival. INTERPRETATION AND CONCLUSIONS: In multiple myeloma a plateau phase of at least 6 months' duration has a higher impact on survival than the degree of response to conventional chemotherapy so plateau duration could be used as target of therapeutic trials. The best way to maintain the plateau phase remains, however, undefined.
Adult↗
Transient response of myeloma clone to pamidronate therapy.
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Adult↗
Serum CA 125 is of clinical value in the staging and follow-up of patients with non-Hodgkin's lymphoma: correlation with tumor parameters and disease activity.
BACKGROUND: CA 125 is a glycoprotein produced by epithelial ovarian tumors and by mesothelial cells; its levels also have been shown to be elevated in patients with non-Hodgkin's lymphoma (NHL). METHODS: The authors evaluated serum CA 125 levels in patients with NHL to elucidate the frequency of this finding, its relationship with other presenting features, and its potential role as tumor marker. One hundred and fifty-seven patients underwent the first CA 125 assessment at onset, 54 at disease recurrence or progression, and 62 during complete remission (CR). RESULTS: Of the 157 patients evaluated at diagnosis (median CA 125: 26 U/mL; range, 2-1400 U/mL), 63 (40%) had increased CA 125 values. Higher CA 125 levels were associated with advanced disease, aggressive histology, mediastinal and/or abdominal involvement, bulky tumor, high tumor burden, effusions, contiguous extranodal extension, high serum lactate dehydrogenase (LDH) activity, and elevated beta2-microglobulin (beta2-M) levels. Parameters identified by multivariate analysis to be independently associated with high CA 125 were: aggressive histology, mediastinal and/or abdominal disease, bulky tumor, high serum LDH activity and beta2-M serum levels, and the presence of effusion (P = 0.0000; explained variation = 0.64). Of the patients presenting with abnormal CA 125 levels, all those who achieved a CR (35) and 3 of the 6 who achieved a partial response had normalization of CA 125 values by the end of treatment. Conversely, CA 125 remained above normal values in 18 nonresponders. All 62 patients evaluated during CR showed normal CA 125 levels. Among patients first evaluated at disease recurrence or progression, 22 of 54 (41%) showed increased CA 125 levels, which were associated with the same parameters of disease found in patients examined at diagnosis. CONCLUSIONS: High serum CA 125 levels were found to correlate with mediastinal and/or abdominal involvement, high tumor mass, and effusions, reflecting the reaction of mesothelial cells to the tumor. Serum CA 125 is a reliable biologic marker for the staging and restaging of patients with lymphoma. Serial measurements are useful, in conjunction with other markers, for monitoring response to treatment.
Adolescent↗
Multiple myeloma in younger patients: the role of age as prognostic factor.
The presenting features of 356 previously untreated multiple myeloma (MM) patients grouped according to age were analyzed in order (a) to elucidate the possible differences in initial clinical and laboratory features between patients younger than 50 years and the older ones and (b) to statistically assess the prognostic value of the parameters considered, with particular emphasis on the prognostic impact of age. Patients were divided into two groups: group I included 61 patients aged less than 50, group II comprised 295 patients aged 50 or more. No significant differences were found between the two groups in terms of either clinical or laboratory initial characteristics. The treatments adopted and the response to therapy did not differ in the two groups. The prognostic value of presenting features was evaluated for the whole cohort by univariate and multivariate analysis, considering both the observed survival rates and survival rates corrected for the effect of other independent causes of death, using a Poisson model. In both models, calcium level (RR 2.33), performance status (RR 1.83), and creatinine (RR 1.69) maintained their independent negative prognostic value. In contrast, the impact of age was different in the two models. In fact, patients younger than 50 seem to have a better prognosis when the observed survival rates are considered, but they show an increased risk of death when the model takes into account the expected mortality of the underlying population. In conclusion, this study shows that the younger cohort of MM patients has no distinctive initial characteristics with respect to older patients. In multivariate analysis, creatinine levels, calcemia, and performance status show a relevant negative independent prognostic value. Regarding the prognostic impact of age, survival seems to be better among patients younger than 50 than in older patients when the observed survival rates are considered but is significantly worse when the mortality of the corresponding general population, is taken into account.
Adult↗
A complex translocation (5;7) in a patient with acute nonlymphocytic leukemia evolved from a myelodysplastic syndrome.
Complete or partial monosomy for the long arms of chromosomes 5 or 7 or both is frequently observed in therapy-related myelodysplastic syndromes and acute nonlymphocytic leukemia. Sporadic cases have been reported in which partial monosomy is due to unbalanced translocations. The patient described herein carries one such rearrangement. 46,XY,t(1;2) (q32;p23),del(5)(q13),der(7)(5qter-->5q22::7p15-->7 q21:),del(12)(p12), resulting in partial monosomy for the long arms of chromosomes 5 and 7 and in partial monosomy for the short arm of chromosome 7.
Chromosome Deletion↗
Molecular epidemiologic characterization of penicillin-resistant Streptococcus pneumoniae invasive pediatric isolates recovered in six Latin-American countries: an overview. PAHO/Rockefeller University Workshop. Pan American Health Organization.
The Pan American Health Organization (PAHO) has conducted a study of Streptococcus pneumoniae in six Latin-American countries: Argentina, Brazil, Chile, Colombia, Mexico, and Uruguay. Sterile site isolates from children aged < or =5 years showing clinical symptoms of pneumonia (as defined by the clinical criteria of WHO), meningitis, sepsis or bacteremia (without infectious foci), arthritis, and peritonitis were the source of most of the invasive pneumococcal isolates collected between the end of 1993 and 1996 in the six participating countries. Partial characterization of these isolates (antibiotic resistance and serotyping) have already been described (Microbial Drug Resistance 3:(2):131-163, 1997). In the next phase of the study, 326 S. pneumoniae isolates with reduced penicillin susceptibility were transferred to the Laboratory of Microbiology at The Rockefeller University for molecular characterization, and a summary and overview of the findings is described in this article. Some of the most interesting findings were as follows: (1) There was a surprisingly high representation of two internationally spread clones, which made up >80% of the strains with penicillin MIC of 1 microg/ml or higher; most of these isolates were recovered in large cities, supporting the likelihood that the source of these clones is through international travel. (2) The frequency of resistance to trimethoprim/sulfamethoxazole was extremely high (present in 85% of all isolates with decreased penicillin susceptibility). (3) None of these isolates was resistant to ofloxacin, and macrolide resistance was rare (present in 6.4% of the isolates). (4) There was an apparent inverse relationship between level of penicillin resistance and genetic diversity. (5) There were striking differences in the "microbiologic profiles" of the six different Latin-American countries.
Child↗
Penicillin-resistant Streptococcus pneumoniae in Argentina: frequent occurrence of an internationally spread serotype 14 clone.
Six Latin-American countries participated in an epidemiological surveillance study conducted by the Pan American Health Organization in order to determine the relative prevalence of capsular types and antimicrobial resistance patterns of Streptococcus pneumoniae (SPN) causing invasive infections in children <5 years of age. In Argentina, the incidence of penicillin resistance (PR) was 24.4%, and it was significantly associated with serotype 14 (p < 0.001). The chromosomal DNA of 56 of those SPN isolates, 39 PR and 17 susceptible, was digested with SmaI and resolved by PFGE. Eighty-two percent (32/39) of the PR isolates shared characteristics with the widely spread International Spanish/French clone (clone B). All members of clone B except one expressed serotype 14, with the exception of one isolate that expressed serotype 19F and probably resulted from an in vivo capsular transformation event. Only a single isolate shared features with the 23F International Spanish/USA clone (clone A). The 17 penicillin-susceptible (PS) SPN isolates presented an enormous degree of variation in the chromosomal background, expressing 12 serotypes and 13 PFGE patterns. The data suggest that over 80% of the SPN-PR isolates in Argentina were imported, and this confirms the importance of the geographic spread of SPN clones in South America.
Argentina↗
Spread of a methicillin-resistant and multiresistant epidemic clone of Staphylococcus aureus in Argentina.
One hundred forty-eight recent methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from 13 hospitals in Argentina were examined for antibiotic susceptibility and clonal type, using hybridization with DNA probes specific for mecA and Tn554, and pulsed-field gel electrophoresis (PFGE) of chromosomal SmaI digests. The majority of the isolates (62.2%) shared the common PFGE B pattern and carried variants of mecA and Tn554 polymorphs characteristic of an MRSA clone widely spread in Brazilian hospitals. Similarly to the Brazilian isolates, the MRSA clone recovered in the Argentinian hospitals (XI::B::B) and its close relatives (XI::B'::B, XI::AA::B, XI::M::B, XI::omega omega::B, and III::W::B) showed susceptibility to spectinomycin and resistance to numerous antibacterial agents, including beta-lactams, tetracycline, aminoglycosides, macrolides, trimethoprim/sulfamethoxazole, ciprofloxacin, and fosfomycin, and more than 60% of the isolates were also resistant to chloramphenicol and rifampin. The XI::B::B MRSA clone represented the majority of isolates recovered in most of the hospitals, nine of which were located in the city of Buenos Aires, three in the province of Buenos Aires, and one in the province of Tucumán, 1,312 km northwest of the city of Buenos Aires. The observations document further geographic expansion of this South American MRSA clone across national boundaries.
Anti-Bacterial Agents↗
Molecular characterization of penicillin-resistant Streptococcus pneumoniae isolates causing respiratory disease in the United States.
Three hundred twenty-eight (328) penicillin-resistant Streptococcus pneumoniae isolates collected in 39 states of the United States between October, 1996, and March, 1997, from (mostly adult) patients with respiratory disease were characterized by microbiological, serological, and molecular fingerprinting techniques, including determination of chromosomal macrorestriction pattern with pulsed-field gel electrophoresis (PFGE) and hybridization with DNA probes specific for various antibiotic resistance genes. The overwhelming majority of the isolates were in five serogroups (23, 6, 19, 9, 14). All isolates had penicillin MIC values of at least 2 microg/ml, but the collection also included isolates with MIC values as high as 16 microg/ml. Virtually all isolates (96.6%) were resistant to trimethoprim/sulfamethoxazole (SXT) and many isolates were also resistant to chloramphenicol (43%), tetracycline (55%), and erythromycin (65%). Resistance to levofloxacin was extremely rare. The molecular fingerprinting methods showed that a surprisingly large proportion (167 out of 328, or 50.9%) of the isolates belonged to two international epidemic clones of S. pneumoniae: clone A (127, or 38.7%) with properties indistinguishable from that of the 23F multiresistant "Spanish/USA" clone widely spread in Europe, Asia, Latin America, and South Africa, and clone B (40, or 12.2%) belonging to the "French" serogroup 9/14 clone widely spread in Europe and South America. Virtually all members of clone A were also resistant to chloramphenicol (cat+), tetracycline (tetM+), and SXT, and about 75% were also resistant to erythromycin (mefE+ or ermB+). Close to 30% (39 out of 127) of the clone A isolates expressed anomalous serotypes (primarily serotypes 19 and 14, and nontypable) and most likely represented spontaneous capsular transformants. Most of the 40 isolates (35/40) belonging to clone B expressed serotype 9, with five of the isolates expressing serotypes 14 or 19, or were nontypable. All members of this clone were resistant to penicillin and SXT with only occasional isolates showing resistance to macrolides, tetracycline, and chloramphenicol. The combination of microbiological tests and DNA hybridizations also allowed the identification of unusual strains, for instance, isolates that reacted with the tetM or mefE DNA probes without showing phenotypic antibiotic resistance, an isolate showing phenotypic macrolide resistance without hybridizing with either the ermB or mefE DNA probes, or isolates that hybridized with both of these DNA probes. In addition to clones A and B, another large portion of the S. pneumoniae isolates (112 of 328, or 34.1%) was represented by eight clusters, each with a unique PFGE type. These clusters, together with the clone A and clone B isolates, made up 85% of all the penicillin-resistant isolates identified in this survey in the United States. Both international clones and the unique clusters showed wide geographic dispersal: Clone A was present in 30 of the 39 states and clone B in 18. The data suggest that the major mode of spread of penicillin-resistant pneumococci in the United States is by clonal expansion and that the most significant components (clones A and B) have been imported into the United States from abroad.
Adult↗
Management of acute promyelocytic leukemia relapse in the ATRA era.
BACKGROUND AND OBJECTIVE: The use of all-trans retinoic acid (ATRA) has changed the natural course of acute promyelocytic leukemia (APL), increasing the percentage of lasting complete remissions. However, management of the few relapses remains undefined. The purpose of the present study was to evaluate the different behavior of APL patients relapsed after induction chemotherapy which had or had not included ATRA. DESIGN AND METHODS: We retrospectively studied 8 patients (3 male and 5 female) who had relapsed after a clinical and molecular complete remission (CR). Five patients relapsed after conventional chemotherapy including anthracyclines, without ATRA which was not available at the onset (group A), 3 relapsed after induction treatment according to AIDA protocol (Idarubicin + ATRA) (group B). Seven patients had both molecular and clinical relapses, 1 (group B) had only a molecular relapse. The median first CR duration was 33 months (range 8-63). To induce a second CR all patients were treated with ATRA 45 mg/m2/day given orally until CR, combined with mitoxantrone 6 mg/m2/day for 6 days and cytarabine 1 g/m2/day for 6 days. RESULTS: Seven out of 8 patients (87.5%) achieved second CR, 1 (group A) did not respond and died within two months. Second CR duration was 21, 43+, 56+, 62+ months in group A and 5, 10, 12+ (with molecular relapse) months in group B. Therefore, only one patient relapsed in group A, while all the group B patients relapsed. INTERPRETATION AND CONCLUSIONS: ATRA combined with chemotherapy is an effective approach to treating APL relapse. It produces a high incidence of second CR with an acceptable toxicity. The duration of the second CR seems, however, to be longer in patients never treated with ATRA before than in patients who relapsed after the AIDA protocol. Therefore, it might be appropriate to adopt more aggressive protocols in this latter subset of patients.
Adolescent↗
Thrombotic events are not exclusive to the remission induction period in patients with acute lymphoblastic leukemia: a report of two cases of cerebral sinus thrombosis.
It is well established that in acute lymphoblastic leukemia (ALL) patients L-asparaginase (L-Ase) provokes thrombotic events reducing coagulation inhibitors in both adults and children. A tight correlation between thrombotic and hemorrhagic complications and ALL has also been hypothesized because of the high incidence of disseminated intravascular coagulation (DIC) found during the early period of chemotherapeutic treatment apart from L-Ase. All the authors reporting on this subject, however, consider the remission induction phase of treatment the most risky, if not exclusive, for the development of a thrombotic event, in particular if it includes the administration of L-Ase. We report here two cases of ALL patients who experienced a cerebral sinus thrombosis in a later phase of treatment, demonstrating that the thrombotic risk is surely exacerbated by chemotherapy but is not exclusive to the remission induction period.
Adult↗
Distribution of capsular types and penicillin-resistance of strains of Streptococcus pneumoniae causing systemic infections in Argentinian children under 5 years of age. Streptococcus pneumoniae Working Group.
Streptococcus pneumoniae (SPN) is the most common cause of invasive infections in children, with high levels of mortality in developing countries. An increase in frequency of penicillin-resistant strains is reported in most parts of the world. A study was undertaken in Argentina and 5 other countries of the region, to determine the type distribution and penicillin resistance rate of SPN isolated from invasive infections in children less than 5 years old. Between June 1994 and March 1996, a total of 505 SPN isolated from sterile sites were collected from 15 hospitals located in 9 cities of different geographic areas. Clinical and epidemiological data from 443 children were analyzed. Sixty five percent SPN were isolated from children less than 2 years old. Pneumonia was the clinical diagnosis in 58% of the cases, meningitis in 22%, and sepsis in 10.6%. Isolates were recovered from blood (51.2%), pleural fluid (22.7%), CSF (20.7%), and other sterile sites (5.4%). Thirty different pneumococcal capsular types were identified and the 10 most frequent in descending order were: 14, 5, 1, 6A/6B, 7F, 9V, 19F, 19A, 16F y 23F, representing 89.3% of the total. Overall, 13.1% of isolates showed intermediate resistance to penicillin while 11.3% showed high resistance. Lethality was 8.8%, without correlation with penicillin-resistance and/or type. These result should be used in selecting the optimal combination of specific types for a conjugate vaccine, useful in children less than 2 years old and for considering therapeutic strategies for invasive pneumococcal infections.
Argentina↗
Clinical relevance of all-trans retinoic acid pharmacokinetics and its modulation in acute promyelocytic leukemia.
Acute promyelocytic leukemia (APL) is uniquely sensitive to treatment with all-trans retinoic acid (ATRA) which exerts its action via a well-documented cytodifferentiating mechanism. The combination of this retinoid with anthracyclines gives high percentages of complete remission and is now considered the optimal induction treatment for APL patients. Continuous treatment with ATRA, however, induces accelerated drug catabolism, with progressive decline in plasma drug concentrations potentially to below the levels required to maintain differentiation of leukemic cells. This process, which occurs rapidly and consistently has led to the hypothesis that the development of acquired clinical resistance to ATRA in APL has a pharmacologic basis. The rapid autoinduction of the hypercatabolic state precludes maintenance with continuous ATRA oral dosing, and is a limitation of better use of the drug both in APL and in other disorders in which it could be beneficial. Here we briefly review the pharmacologic alterations of ATRA metabolism induced by continuous oral administration, the clinical implications of this phenomenon, and the strategies currently under investigation to prevent or overcome the induced catabolism of this retinoid.
Administration, Oral↗