Treatment with 13-cis-retinoic acid in transfusion-dependent patients with myelodysplastic syndrome and decreased toxicity with addition of alpha-tocopherol

Use of Oral Supplements and Topical Adjuvants for Isotretinoin-Associated Side Effects: A Narrative Review

Acne is a chronic inflammatory disease of the pilosebaceous unit with a multifactorial etiology and is one of the most common conditions treated by dermatologists and primary care physicians. Within an extensive and evolving treatment landscape, oral isotretinoin has demonstrated efficacy for treatment of severe, recalcitrant acne. Several side effects of isotretinoin have been reported, including laboratory abnormalities, mucocutaneous, and musculoskeletal effects, which may reduce compliance and patient satisfaction with treatment. In this narrative review, we aim to review the efficacy and safety profile of oral supplements or topical adjuvant therapies in mitigating isotretinoin-associated mucocutaneous and musculoskeletal side effects. Oral supplements reviewed include omega-3 fatty acids, vitamin E, folic acid and vitamin B12, antihistamines, l-carnitine, biotin, and combined oral supplements. Topical adjuvants include a hyaluronic acid, biosaccharide gum-2, and glycerine gel-cream; a nongreasy, noncomedogenic, fragrance-free moisturizing cream; dexpanthenol; trichloroacetic acid; and a combination cream. Most of the supplements and topical adjuvants demonstrated efficacy with an adequate level of supporting evidence and no reported adverse events, indicating an adequate safety profile. Patients on isotretinoin may benefit from using oral supplements and topical adjuvants to minimize primarily mucocutaneous side effects, increase adherence to treatment, and thereby improve overall outcomes.

Antioxidants as precision weapons in war against cancer chemotherapy induced toxicity - Exploring the armoury of obscurity

Cancer is the leading cause of mortality worldwide, accounting for almost 13% of deaths in the world. Among the conventional cancer treatments, chemotherapy is most frequently carried out to treat malignant cancer rather than localised lesions which is amenable to surgery and radiotherapy. However, anticancer drugs are associated with a plethora of side effects. Each drug, within every class, has its own set of adverse reactions which may cause patient incompliance and deterioration of the quality of life. One of the major causes of adverse reactions, especially for drugs targeting DNA, is the excessive production of reactive oxygen species (ROS) and subsequent build up of oxidative stress. To curb these undesired side effects, several dietary supplements have been tested, amongst which antioxidants have gained increasing popularity as adjuvant in chemotherapy. However, many oncologists discourage the use of antioxidant rich food supplements because these may interfere with the modalities which kill cancer by generating free radicals. In the present review, all studies reporting concomitant use of several antioxidants with chemotherapy are indiscriminately included and discussed impartially.

The effect of supplementation of thirteen different antioxidants and their analogues as a single agent or in combination with chemotherapy has been compiled in this article. The present review encompasses a total of 174 peer-reviewed original articles from 1967 till date comprising 93 clinical trials with a cumulative number of 18,208 patients, 56 animal studies and 35 in vitro studies. Our comprehensive data suggests that antioxidant has superior potential of ameliorating chemotherapeutic induced toxicity. Antioxidant supplementation during chemotherapy also promises higher therapeutic efficiency and increased survival times in patients.

Combination of 13-Cis retinoic acid and lovastatin: marked antitumor potential in vivo in a pheochromocytoma allograft model in female athymic nude mice

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

Chemoprevention of lung cancer: concepts and strategies

Lung cancer develops in a stepwise fashion, with an accumulation of molecular alterations progressing through preinvasive steps to invasive disease. This progression could be arrested or reversed through pharmacologic treatments, which are known as cancer chemoprevention. Preclinical and clinical findings relating to different classes of candidate chemopreventive agents provide support for this strategy as an active and promising approach for controlling this disease.

Isotretinoin treatment induces oxidative toxicity in blood of patients with acne vulgaris: a clinical pilot study

Acne vulgaris is the one of the most common skin diseases. Although isotretinoin (13-cis-retinoic acid) is an effective and well-tolerated medication, it has a wide range of side effects. Because the effects of isotretinoin on oxidant and antioxidant systems have not yet been clarified, we investigated plasma and erythrocyte antioxidant vitamins, lipid peroxidation (LP), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) values in patients with acne vulgaris before and after isotretinoin treatment. The study was performed on the blood plasma and erythrocytes of 31 acne vulgaris patients. Blood samples were taken from the patients before treatment and after isotretinoin (oral and 0·5-0·7 mg·kg(-1)) treatment for 2 months. Plasma amtioxidant vitamins, erythrocyte malondialdehyde, GSH and GSH-Px levels were measured. Plasma vitamin E (p < 0·001), lipid peroxidation (LP) and serum high-density lipoprotein cholesterol (p < 0·001) values were significantly lower in the treatment group than in the pre-treatment group, although erythrocyte LP (p < 0·001), GSH (p < 0·01) and GSH-Px (p < 0·001), aspartate aminotransferase (p < 0·05), alanine aminotransferase (p < 0·05), density lipoprotein cholesterol (p < 0·001) and total cholesterol (p < 0·01) levels were significantly higher in the treatment group than in the pre-treatment group. Vitamins A, C and β-carotene concentrations did not change significantly between the two groups. In conclusion, the results of the current study indicate that isotretinoin treatment induces oxidative stress and liver damage by decreasing plasma vitamin E and increasing erythrocytes GSH-Px, GSH and liver enzyme values.

Optimizing therapeutic efficacy of chemopreventive agents: A critical review of delivery strategies in oral cancer chemoprevention clinical trials

Due to its characterized progression from recognized premalignant oral epithelial changes (i.e., oral epithelial dysplasia) to invasive cancer, oral squamous cell carcinoma represents an optimal disease for chemopreventive intervention prior to malignant transformation. The primary goal of oral cancer chemoprevention is to reverse, suppress, or inhibit the progression of premalignant lesions to cancer. Over the last several decades, numerous oral cancer chemoprevention clinical trials have assessed the therapeutic efficacy of diverse chemopreventive agents. The standard of care for more advanced oral dysplastic lesions entails surgical excision and close clinical follow-up due to the potential (~33%) for local recurrence at a similar or more advanced histological stage. The purpose of this review was to identify prominent oral cancer chemoprevention clinical trials, assess their overall therapeutic efficacy, and delineate effects of local versus systemic drug administration. In addition, these compiled clinical trial data present concepts for consideration in the design and conduction of future clinical trials.

Cyclin D1 and cancer development in laryngeal premalignancy patients

In a previous trial, we found that combined 13-cis-retinoic acid, IFN-alpha, and alpha-tocopherol more effectively reversed advanced premalignant lesions of the larynx than of the oral cavity and that cyclin D1 (CD1) G/A870 single nucleotide polymorphism correlated with cancer risk. We conducted the present trial primarily to confirm the clinical activity of the combination in advanced laryngeal premalignancy and to confirm and extend our findings on CD1, both genotype and protein expression, in association with cancer risk in this setting. Twenty-seven moderate-to-severe laryngeal dysplasia patients underwent induction with combined 13-cis-retinoic acid daily, alpha-IFN twice weekly, and alpha-tocopherol daily for 1 year; 14 nonprogressing patients then were randomized to maintenance fenretinide or placebo for 2 years. During induction, two patients had pathologic complete responses, six had partial responses (30% overall response rate), and five developed laryngeal cancer. There were no significant differences between maintenance fenretinide and placebo in response or cancer rates. Ten patients developed cancer overall. Twenty-four patients were evaluated for the CD1 G/A870 genotype, and 23 for pretreatment and posttreatment CD1 protein expression. Consistent with our earlier report, shorter cancer-free survival was associated with the CD1 AA/AG genotype (P = 0.05). Extending our earlier work, high CD1 expression was associated with worse cancer-free survival overall (P = 0.04) and within each CD1 genotype group. These findings support CD1 genotype and protein expression as important risk markers for laryngeal cancer and suggest future trials targeting upstream regulators of CD1 transcription.

Treatment of myelodysplastic syndrome with isolated del(5q) including bands q31-q33 with a combination of all-trans-retinoic acid and tocopherol-alpha: a phase II study

All-trans-retinoic acid (ATRA) alone or in combination with cytokines and vitamins has been shown to stimulate erythropoiesis in low-risk myelodysplastic syndromes (MDS). We performed a phase II study on 29 patients with MDS and isolated del(5q) including bands q31-q33 to determine the efficacy and safety of ATRA in combination with tocopherol-alpha. All patients had low/intermediate-1 risk MDS according to the international prognostic scoring system. They received 45 mg/m(2) ATRA on days 1 to 90, and 90 mg/m(2) on days 91 to 180. Tocopherol dosage was 600 IU three times daily. Twenty-four patients completed dose level I, and 12 patients dose level II. Eighty-six percent of patients experienced side effects. Thirty discontinued the drug treatment due to such events as skin reactions, cheilitis, conjunctivitis, joint pain, creatinine increase, or CNS symptoms. One patient (3%) achieved a major erythroid response resulting in transfusion independence throughout the study. Four patients (14%) achieved a minor erythroid response with >50% reduction of transfusion needs. None of the participants had a cytogenetic response. There was no significant improvement in quality of life among responding patients as measured by the European Organization for the Research and Treatment of Cancer (EORTC) quality of life questionnaire. Based on these results, the combination of ATRA and tocopherol-alpha is not recommended for the treatment of del(5q) MDS.

Vitamin E does not reduce the side-effects of isotretinoin in the treatment of acne vulgaris

BACKGROUND

Isotretinoin is widely used in the treatment of severe, recalcitrant, nodular acne. Mucocutaneous side-effects are seen in the great majority of patients and some of them have elevations in their serum lipid and liver enzyme profiles. Recently, it has been shown that addition of vitamin E decreased the toxicity of high-dose retinoids.

OBJECTIVE

The purpose of this investigator-blinded, randomized study was to assess whether vitamin E would reduce the side-effects of isotretinoin in the treatment of acne vulgaris.

METHODS

Eighty two patients were randomly assigned to one of two treatment groups with isotretinoin (1 mg/kg/day) alone or combined with vitamin E (800 IU/day). The treatment duration was 16 weeks. Mucocutaneous side-effects such as facial erythema, facial dryness, cheilitis and serum lipid and liver enzyme profiles were assessed.

RESULTS

There was no difference in the incidence and severity of side-effects related to isotretinoin between the two treatment groups.

CONCLUSION

Eight hundred IU/day vitamin E did not improve the side-effects of 1 mg/kg/day of isotretinoin in the treatment of acne vulgaris.

Retinoids and their receptors in cancer development and chemoprevention

Retinoids play an important role in regulating the growth and differentiation of normal, premalignant and malignant cell types, especially epithelial cells, mainly through interaction with two types of nuclear receptors: retinoic acid receptors (RARalpha, beta and gamma) and retinoid X receptors (RXRalpha, beta and gamma). Vitamin A deficiency in experimental animals has been associated with a higher incidence of cancer and with increased susceptibility to chemical carcinogens. This is in agreement with the epidemiological studies indicating that individuals with a lower dietary vitamin A intake are at a higher risk to develop cancer. At the molecular level, aberrant expression and function of nuclear retinoid receptors have been found in various types of cancer including premalignant lesions. Thus, aberrations in retinoid signaling are early events in carcinogenesis. Retinoids at pharmacological doses exhibit a variety of effects associated with cancer prevention. They suppress transformation of cells in vitro, inhibit carcinogenesis in various organs in animal models, reduce premalignant human epithelial lesions and prevent second primary tumors following curative therapy for epithelial malignancies such as head and neck, lung, liver, and breast cancer.

Acne therapy: clinical pearls

Several classes of medications successfully treat acne. Systemic and topical retinoids, systemic and topical antimicrobials, and systemic hormonal therapy are the major categories. Failure of therapy may result from drug interactions, antibiotic resistance, or coexisting conditions; therefore, a detailed history including these points should be used to decide which therapy is appropriate for each patient. Furthermore, one must consider the potential side effects of each treatment and make sure that (1) the benefits outweigh the risks of the treatment, (2) the side effects can be avoided by adding another agent, or (3) the side effects can be safely treated.

Safety issues in isotretinoin therapy

Isotretinoin (Accutane, Roche Laboratories Inc, Nutley, NJ) is an important drug, not only for the treatment of severe acne, but also for other diagnoses and in chemoprevention settings. Because the use of isotretinoin is increasing, it is important for physicians to be aware of the adverse events, toxicities, and management issues related to its use. The most important issue is that of congenital defects, which has resulted in new pregnancy prevention policies and programs implemented by the manufacturer. A relatively new concern is that of depression associated with isotretinoin use, also resulting in new policies placed by the manufacturer and the FDA. The most common adverse effects observed during treatment are mucocutaneous and ocular in nature, but laboratory abnormalities and effects in the nervous, musculoskeletal, gastrointestinal, pulmonary, hematologic, and other systems are also described. Additionally, potential drug interactions, follow-up, and toxicity prevention measures are discussed.

Malignancy: Current Clinical Practice: Current Therapeutic Options in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are characterized initially by ineffective hematopoiesis and subsequently the frequent development of acute myelogenous leukemias (AML). During the last 15 years, important progress has been made in the understanding of the biology and prognosis of myelodysplastic syndromes. Risk-adapted treatment strategies were established due to the high median age (60-75 years) of MDS-patients and the individual history of the disease (number of cytopenias, cytogenetical changes, transfusion requirements). The use of allogeneic bone marrow transplantation for MDS patients currently offers the only potentially curative treatment, but this treatment modality is not available for the most of the "typical" MDS-patients aged >60 years. Based on in-vitro findings analyzing the potential of several agents to differentiate or to stimulate hematopoietic progenitor cells a number of therapeutic options were evaluated in clinical trials: hematopoietic growth factors (e.g. erythropoietin, G-CSF), differentiation inducers (e.g. retinoids), or cytoprotective substances (amifostine). The role of immunsuppressive agents (antithymocyte globulin, cyclosporine A) either alone or in combination is being actively investigated. Using intensive cytotoxic treatment in patients with advanced MDS or AML after MDS complete remission rates comparable with those known from the treatment of de novo AML were reported. The therapy related toxicity (early death rate <10%) was reduced by using G-CSF given prior ("Priming") and/or after the cytotoxic treatment.

Combined interferon-alfa, 13-cis-retinoic acid, and alpha-tocopherol in locally advanced head and neck squamous cell carcinoma: novel bioadjuvant phase II trial

PURPOSE

Retinoids and interferons (IFNs) have single-agent and synergistic combined effects in modulating cell proliferation, differentiation, and apoptosis in vitro and clinical activity in vivo in the head and neck and other sites. Alpha-tocopherol has chemopreventive activity in the head and neck and may decrease 13-cis-retinoic acid (13-cRA) toxicity. We designed the present phase II adjuvant trial to prevent recurrence or second primary tumors (SPTs) using 13-cRA, IFN-alpha, and alpha-tocopherol in locally advanced-stage head and neck cancer.

PATIENTS AND METHODS

After definitive local treatment with surgery, radiotherapy, or both, patients with locally advanced SCCHN were treated with 13-cRA (50 mg/m(2)/d, orally, daily), IFN-alpha (3 x 10(6) IU/m(2), subcutaneous injection, three times a week), and alpha-tocopherol (1,200 IU/d, orally, daily) for 12 months, with a dose modification. Screening for recurrence or SPTs was performed every 3 months.

RESULTS

Tumors of 11 (24%) of the 45 treated patients were stage III, and 34 (76%) were stage IV. Thirty-eight (86%) of 44 patients completed the full 12-month treatment (doses modified as needed). Toxicity generally was consistent with previous IFN and 13-cRA reports and included mild to moderate mucocutaneous and flu-like symptoms; occasional significant fatigue (grade 3 in 7% of patients), mild to moderate hypertriglyceridemia in 30% of patients who continued treatment along with antilipid therapy, and mild hematologic side effects. Six patients did not complete the planned treatment because of intolerable toxicity or social problems. At a median 24-months of follow-up, our clinical end point rates were 9% for local/regional recurrence (four patients), 5% for local/regional recurrence and distant metastases (two patients), and 2% for SPT (one patient), which was acute promyelocytic leukemia (ie, not of the upper aerodigestive tract). Median 1- and 2-year rates of overall survival were 98% and 91%, respectively, and of disease-free survival were 91% and 84%, respectively.

CONCLUSION

The novel biologic agent combination of IFN-alpha, 13-cRA, and alpha-tocopherol was generally well tolerated and promising as adjuvant therapy for locally advanced squamous cell carcinoma of the head and neck. We are currently conducting a phase III randomized study of this combination (v no treatment) to confirm these phase II study results.

Concomitant administration of vitamin E does not change the side effects of isotretinoin as used in acne vulgaris: a randomized trial

BACKGROUND

Isotretinoin treatment is frequently associated with reversible, dose-related side effects. Recent studies claimed that combining vitamin E with high-dose isotretinoin ameliorated isotretinoin-induced side effects.

OBJECTIVE

The purpose of this double-blind, randomized study was to determine the effects of a fixed dose of vitamin E on the side effects of isotretinoin for treatment-resistant acne vulgaris.

METHODS

One hundred forty subjects were randomly assigned to one of two treatment programs with isotretinoin (1 mg/kg) together with either vitamin E (800 IU/day) or a vitamin E placebo for 20 weeks. The incidence, severity, and duration of the side effects (eg, dry eyes, dry lips) were assessed.

RESULTS

A fixed 800 IU/day dose of vitamin E did not improve the incidence, severity, or duration of side effects associated with isotretinoin (1 mg/kg per day).

CONCLUSION

Vitamin E did not significantly ameliorate retinoid side effects when combined with 1 mg/kg of isotretinoin in the treatment of acne.

Oral 9-cis retinoic acid (Alitretinoin) in the treatment of myelodysplastic syndromes: results from a pilot study

A multicenter phase II study was initiated to investigate the efficacy, toxicity and tolerability of an oral regimen of 9-cis retinoic acid (9CRA) as a differentiation-inducing agent stimulating both retinoic acid receptor (RAR) and retinoic X receptor (RXR). Thirty patients with myelodysplastic syndromes (MDS) were enrolled into the study. The MDS subtypes were distributed as follows: 14 refractory anaemia (RA), four refractory anaemia with ringed sideroblasts (RARS), and 12 refractory anaemia with excess blasts (RAEB). The age ranged from 40 to 81 years (median 70). None of these had previously received treatment for MDS other than supportive therapy. 9CRA (Alitretinoin capsules, kindly provided by Allergan-Ligand Retinoid Therapeutics) was given daily at 60 mg/m2 p.o. for 1 week, followed by an intra-patient escalation to 100 mg/m2 during the second week, up to a maximum of 140 mg/m2. The planned treatment duration was 48 weeks. Twenty-five were available for assessment. One patient (4%) with RA achieved complete hematological remission. Four (16%), two with RA, two with RAEB, had minor responses resulting in decreased transfusion requirements or increased neutrophils. Thus, the overall response rate was 20% in evaluable patients with MDS and 17% in the study group on an intention-to-treat basis. The most frequent side-effects included headache (77%), dry skin (57%), arthralgias (30%), and rash (23%). In conclusion, although modest responses were noted in this study, the treatment tolerability was suboptimal. It is conceivable that a lower dosage schedule may be efficacious and better tolerated so enabling prolonged exposure which may be required to induce a differentiation effect.

Prolonged complete remission of myelodysplastic syndrome treated with danazol, retinoic acid and low-dose prednisone

Myelodysplastic syndrome (MDS) is a diverse group of clonal hematologic neoplasms. Different medications have been tried in MDS; however, no effective treatment has been yet established. We report a patient with MDS who achieved a complete remission in response to combination therapy of danazol, retinoic acid, and prednisone. A 53-year-old female presented with pancytopenia, macrocytosis, and hypercellular bone marrow with erythroid hyperplasia and dysplasia and 10% ringed sideroblasts. Cytogenetic studies revealed the presence of two abnormal clones. She was diagnosed as having MDS-refractory anemia and was given blood transfusions to maintain blood cell counts at acceptable levels. At the same time, she was started on a combination of danazol (600 mg/day), retinoic acid (100 mg/day), and prednisone (10 mg every other day). Fourteen months later, the patient was in complete hematologic remission; she had normal peripheral blood count, and the blood smear showed normal morphology. Bone marrow studies revealed normal trilineage hematopoiesis. She was continued on the same combination treatment for 86 months, and she remained in complete clinical remission. Eighty-eight months from diagnosis, she relapsed with acute myeloid leukemia. This is the first reported case of MDS-RA that sustained a complete hematologic remission for a prolonged period in response to this combination treatment. This report indicates that restoration of normal hematopoiesis, prolongation of disease-free survival, and delay in the transformation to acute leukemia may be achieved by this combination of treatment in a subset of patients with MDS, especially refractory anemia with severe thrombocytopenia.

Advances in psoriasis therapy

New uses of older drugs, new combinations of treatments, and new phototherapeutic modalities are enabling clinicians to offer patients safer and more effective treatments. New vehicles for topical delivery of older treatments have created more cosmetically elegant preparations that are better accepted by patients. This article discusses new developments in topical therapy, phototherapy, oral therapy, and injectable therapy for psoriasis.

Estrone potentiates myeloid cell differentiation: a role for 17 beta-hydroxysteroid dehydrogenase in modulating hemopoiesis

Hormones such as 1 alpha, 25-dihydroxy vitamin D3 (D3), all-trans retinoic acid, and 9-cis retinoic acid stimulate differentiation of myeloid progenitor cells via their interaction with specific hormone receptors. However, the sensitivity of cells to these agents is not merely governed by the expression of their receptors and the availability of ligand to bind them. Recent studies from our group suggested that the actions of D3 and retinoids on myelopoiesis also are influenced by endogenous mechanisms involving other steroid hormones. In this study we examined the influence of local estrogen metabolism on the differentiation of HL60 cells and normal primitive myeloid progenitor cells. Quantitative thin-layer chromatography (TLC) analyses showed that HL60 and normal cells are able to generate estrone (E1) from estradiol (E2). Neither cell population generated significant amounts of E2 from E1. Reverse transcriptase polymerase chain reaction and Northern analyses confirmed that normal and leukemic myeloid progenitor cells expressed mRNA for the type I and IV isoforms of 17 beta-hydroxysteroid dehydrogenase. Conversion of E2 to E1 was upregulated within 24 hours when HL60 cells were treated with either all-trans retinoic acid or D3 at doses that induce their differentiation toward neutrophils or monocytes, respectively. Similarly, D3-induced monocyte differentiation of normal myeloid progenitor cells was associated with increased capacity to generate E1 from E2. When HL60 cells or normal myeloid progenitor cells were exposed to exogenous E1 they became more sensitive to the differentiation-inducing effects of D3. Data presented provide further evidence for the local modulation of myelopoiesis by intracrine mechanisms. In particular, our findings suggest that local metabolism of steroids by normal as well as leukemic myeloid cells influences their responsiveness to D3 and retinoids.

Novel biologic approaches to hematologic malignancies

Biologic agents have made a major impact on the treatment of hematologic malignancies and will continue to play a major role as we better understand their function in normal and malignant cell regulation. The examples provided in this chapter are a brief introduction to the potential of these agents. Many have yet to be used in conjunction with current cytotoxic therapy in these diseases, and perhaps combinations will prove even more successful. This possibility provides substantial ground for further investigation and therapy.

The emerging role of retinoids and retinoic acid metabolism blocking agents in the treatment of cancer

BACKGROUND

Although significant advances have been made in the treatment of some malignancies, the prognosis of patients with metastatic tumors remains poor. Differentiating agents redirect cells toward their normal phenotype and therefore may reverse or suppress evolving malignant lesions or prevent cancer invasion. In addition, they offer a potential alternative to the classic cytostatic drugs.

METHODS

The purpose of this review was to examine the current and potential future roles of differentiating agents in the treatment of cancer.

RESULTS

Initial studies with differentiating agents focused on retinoid therapy. Although retinoids have shown some clinical success, their widespread use has been limited by resistance and, in the chemopreventive setting, toxicity. This has led to the synthesis of a number of new retinoids that currently are undergoing clinical investigation. A further approach to overcoming the drawbacks associated with exogenous retinoids has been to increase the levels of endogenous retinoic acid (RA) by inhibiting the cytochrome P450-mediated catabolism of RA using a novel class of agents known as retinoic acid metabolism blocking agents (RAMBAs). Liarozole, the first RAMBA to undergo clinical investigation, preferentially increases intratumor levels of endogenous RA resulting in antitumor activity.

CONCLUSIONS

Although studies using exogenous retinoids in this setting have not yet fulfilled their initial promise, studies with a growing set of synthetic retinoids are ongoing. Furthermore, modulation of endogenous retinoids may offer a significant new potential treatment for cancer.

A pilot trial of 13-cis-retinoic acid and alpha-tocopherol with recombinant human erythropoietin in myelodysplastic syndrome patients with progressive or transfusion-dependent anemias. The Central Pennsylvania Oncology Group

A pilot study was performed to determine the efficacy of 13-cis-retinoic acid (CRA) and alpha-tocopherol (AT) with increasing doses of recombinant human erythropoietin (rHuEPO) in anemic patients with primary myelodysplastic syndrome (MDS), to determine response rate and to determine the dose requirement and long-term effects of rHuEPO therapy on the transition to acute non-lymphocytic anemia and survival of these patients. Twenty-four consecutive MDS patients were entered into the study. Patients were stratified according to their FAB classification at study entry. Therapy consisted of a 6 month trial of CRA (100 mg m(-2) day(-1) and AT (800 mg day(-1)) with rHuEPO (150 units kg(-1) body weight subcutaneously three times a week). The rHuEPO dose was escalated to daily doses at 2 months, and 300 U kg(-1) body weight given three times a week for another 2 months and continuing therapy after 6 months in responsive patients. Response was measured by elimination of transfusions requirement (partial response, PR) and normal hemoglobin level and complete blood counts (complete response, CR). Observed responses for the 23 evaluable patients were 2 CR and 6 PR (34.8%). Odds ratio analysis showed that patients with anemia alone were 14 times more likely to respond than patients with pancytopenia (p = 0.06). In our study, two patients (8%) transformed to acute leukemia in CRA + AT + rHuEPO-treated patients. Median survival of 34 months with a median follow-up of 17 months (range 3-70 months) was observed. The response rates with the addition of rHuEPO to CRA and AT was similar but occurs earlier at 2 months compared to 6-10 months with CRA and AT alone and did not alter survival. There was no increase in the risk for leukemia in the group treated with rHuEPO. Response to either therapy appeared to be limited to patients in the early stages of MDS.

Induction of Differentiation in Acute Promyelocytic Leukemia Cells by 9-cis Retinoic Acid α-Tocopherol Ester (9-cisTretinoin Tocoferil)

Acute promyelocytic leukemia (APL) has a specific genetic rearrangement between the retinoic acid receptor (RAR)-α gene and the pml nuclear protein gene. All-trans retinoic acid (ATRA) induces granulocytic differentiation of APL-derived cells and is used to treat APL patients. However, ATRA interacts with normal cells with RAR throughout the entire body, and when used at high doses or over a long duration, it induces several adverse effects. The development of drugs that selectively act on APL cells may contribute to increasing the therapeutic efficacy of APL treatment as well as elucidating the mechanisms of response to ATRA. In this study, 9-cis retinoic acid α-tocopherol ester (9CTT) inhibited the proliferation of APL-derived NB4 and HT93 cells and induced differentiation markers, such as granulocytic maturation, nitroblue tetrazolium reduction, and CD11b expression, in these cells. The effects of 9CTT on non-APL cells, including HL-60 and U937 cells, were much weaker than those on APL cells, and tretinoin tocoferil (TT), which is an α-tocopherol ester of ATRA, did not induce the differentiation of APL cells as effectively as 9CTT. The differentiation-inducing effects of 9CTT were inhibited by RAR antagonists. 9CTT and TT similarly induced the transactivating activity of RARs, but were not effective on RXRs. 9CTT downregulated the expression of PML/RAR-α protein more effectively than TT, which suggests that it may be involved in the selectivity of 9CTT against APL cells. Interestingly, 9CTT enhanced the differentiation of APL cells induced by ATRA, 9-cis retinoic acid, and synthetic retinobenzoic acids. Combined with 1α,25-dihydroxyvitamin D3 (VD3), 9CTT also more than additively induced the differentiation of APL cells. Thus, 9CTT, alone or in combination with other retinoids or VD3, may be useful for the treatment of APL.

Induction of Differentiation in Acute Promyelocytic Leukemia Cells by 9-cis Retinoic Acid α-Tocopherol Ester (9-cisTretinoin Tocoferil)

Acute promyelocytic leukemia (APL) has a specific genetic rearrangement between the retinoic acid receptor (RAR)-α gene and the pml nuclear protein gene. All-trans retinoic acid (ATRA) induces granulocytic differentiation of APL-derived cells and is used to treat APL patients. However, ATRA interacts with normal cells with RAR throughout the entire body, and when used at high doses or over a long duration, it induces several adverse effects. The development of drugs that selectively act on APL cells may contribute to increasing the therapeutic efficacy of APL treatment as well as elucidating the mechanisms of response to ATRA. In this study, 9-cis retinoic acid α-tocopherol ester (9CTT) inhibited the proliferation of APL-derived NB4 and HT93 cells and induced differentiation markers, such as granulocytic maturation, nitroblue tetrazolium reduction, and CD11b expression, in these cells. The effects of 9CTT on non-APL cells, including HL-60 and U937 cells, were much weaker than those on APL cells, and tretinoin tocoferil (TT), which is an α-tocopherol ester of ATRA, did not induce the differentiation of APL cells as effectively as 9CTT. The differentiation-inducing effects of 9CTT were inhibited by RAR antagonists. 9CTT and TT similarly induced the transactivating activity of RARs, but were not effective on RXRs. 9CTT downregulated the expression of PML/RAR-α protein more effectively than TT, which suggests that it may be involved in the selectivity of 9CTT against APL cells. Interestingly, 9CTT enhanced the differentiation of APL cells induced by ATRA, 9-cis retinoic acid, and synthetic retinobenzoic acids. Combined with 1α,25-dihydroxyvitamin D3 (VD3), 9CTT also more than additively induced the differentiation of APL cells. Thus, 9CTT, alone or in combination with other retinoids or VD3, may be useful for the treatment of APL.

Tretinoin tocoferil as a possible differentiation-inducing agent against myelomonocytic leukemia

Tretinoin tocoferil is an alpha-tocopherol ester of all-trans retinoic acid (ATRA) and safely used to treat skin ulcers. Tretinoin tocoferil stimulates the formation of granulation tissue in the ulcer, and enhances the migration of guinea pig macrophages and stimulates the proliferation of human skin fibroblasts. These effects are different from those of either ATRA or alpha-tocopherol. Tretinoin tocoferil induces the granulocytic differentiation of human promyelocytic leukemia HL-60 cells, and more than additively enhances cellular differentiation induced by sub-optimal concentrations of ATRA. Tretinoin tocoferil and ATRA synergistically inhibit the proliferation of HL-60 cells, suggesting that tretinoin tocoferil acts differently than ATRA on leukemia cells. Tretinoin tocoferil also enhances the differentiation of HL-60 cells induced by dimethyl sulfoxide, phorbol ester and 1alpha,25-dihydroxyvitamin D3(VD3). Tretinoin tocoferil and VD3 synergistically inhibit the proliferation and induce the differentiation of other myelomonocytic leukemia cells. Toxicity tests in animal models have shown that tretinoin tocoferil is at least 150 times less toxic than ATRA and does not induce teratogenesis. Therefore, the combination of tretinoin tocoferil and VD3 may be useful for treating myelomonocytic leukemia.

Phase I trial of alpha-tocopherol effects on 13-cis-retinoic acid toxicity

BACKGROUND

Retinoids are under intensive study for the treatment and prevention of cancer. Substantial dose-related toxicities of retinoids are a major obstacle to this work. In a recent retrospective analysis of combined 13-cis-retinoic acid (13cRA) and alpha-tocopherol (AT) in myelodysplasia, 13cRA toxicity was reduced significantly and 13cRA activity was enhanced. These results suggested the need for prospective testing of this new combination. This trial tested the hypotheses that At can reduce toxicity of high-dose 13cRA and does not interfere with 13cRA absorption/activity as reflected by reduced 13cRA serum levels.

PATIENTS AND METHODS

This was a phase I trial design in which patients received fixed-dose 13cRA (100 mg/m2/d) plus escalating-dose AT (beginning at 800 IU/d, increased 400 IU/d each month until 2000 IU/d). We collected toxicity data every four weeks from self-report forms, clinical examinations and laboratory studies. AT effects on 13cRA toxicity were determined by comparing maximum toxicity at lowest AT dose with that at highest AT dose. We also measured serum levels of both agents every four weeks.

RESULTS

Of the 45 patients registered, 36 had cancer (active or prior history), 9 had premalignant lesions. Thirty-nine patients could be evaluated for initial-course toxicity; 31 for final course toxicity. Median time on treatment (all patients) was four months (range, 1-9 months); a total of 223 month-long courses of treatment were given. Eighteen percent of patients (7/39) developed grade 3 or 4 toxicity in the initial course. The rates of increase and decrease in 13cRA toxicity associated with increasing AT doses were similar: 36% decreased (11/31), 32% increased (10/31) (P = 0.84). At did not reduce 13cRA serum levels. After initial increases of mean AT plasma levels (17.9 micrograms/ ml at baseline to 45.4 micrograms/ml after first four-week course), subsequent AT plasma increases (< 2-fold) did not keep pace with increased AT doses (2-3-fold). No major activity occurred in the 21 patients with active refractory cancer. The complete response rate in patients with premalignant head-and-neck or lung lesions was 77.8% (7/9), which included two patients previously refractory to 13cRA alone.

CONCLUSION

Although escalating doses of AT did not reduce 13cRA toxicity, the rate of initial-course (including 800 IU/d of AT) high-grade toxicity was substantially lower than that typical of high-dose 13cRA-alone and similar to that typical of low-dose 13cRA-alone. Indeed, a trial of 13cRA-alone followed by 13cRA plus AT may have detected a significant toxicity difference. We did not design such a trial out of ethical concern for known side effects of high-dose 13cRA. The increase in AT serum levels was not proportional with increasing doses of AT, which may explain the lack of a dose-response effect of AT on 13cRA toxicity. Previous trials have established that 13cRA has an approximate 10% complete response rate in oral premalignancy. Our small trial's 77.8% complete response rate in premalignant lesions suggests that AT may enhance 13cRA clinical activity. Future trials of 13cRA plus AT are needed to define this combinations toxicity profile, clinical activity and pharmacokinetics.

Clinical studies in head and neck cancer chemoprevention

Secondary neoplasms represent a major threat for patients with head and neck cancer. The prevention of secondary neoplasms has been a major goal of head and neck cancer chemoprevention efforts. In order to help develop effective strategies, reversal of oral premalignancy has been used as a model for chemoprevention. There is now sufficient data to show the chemopreventive effect in premalignant lesions of some natural compounds and their derivatives. Retinoids are the most studied chemopreventive agents for the treatment of oral leukoplakia. Other compounds with chemopreventive activity are carotenoids, Vitamin E derivatives and Selenium. There are two large prospective, randomized, chemoprevention clinical trials, one in Europe and the other in North America, using prevention of secondary malignancy as the primary study end-point. Until these trials are completed, the use of chemoprevention in head and neck cancer should be limited to clinical trials.

Changes in erythroid progenitor cell and accessory cell compartments in patients with myelodysplastic syndromes during treatment with all-trans retinoic acid and haemopoietic growth factors

Differentiation induction therapy is used in myelodysplastic syndromes (MDS) to improve maturation defects and to restore impaired function of malignant cells. To this end, 18 patients with MDS received either a combination therapy consisting in study 1 of all-trans retinoic acid (ATRA) and granulocyte-colony stimulating factor (G-CSF), or in study 2 of a combination with ATRA, G-CSF, erythropoietin (Epo) and tocopherol. The ANC increased in 19/20 patients in both studies, whereas an increase in haemoglobin concentration, platelet counts or reduction of transfusion requirement was seen in only 8/20 patients, correlating strongly with good BFU-E growth (P < 0.001). To assess the role of accessory cells in the modulation of the haemopoietic response to treatment, we analysed the capacity of peripheral blood monocytes to secrete cytokines (IL-1 beta, IL-6, IL-8, TNF alpha). Secretion of all cytokines was significantly reduced before therapy when compared with healthy controls, but increased during therapy, reaching normal levels for IL-8. These data indicate that a combination therapy with ATRA and cytokines improves impaired cytokine secretion from monocytes and induces a multilineage clinical response in a subgroup of MDS patients characterized by an almost intact erythroid compartment. In contrast, induction of TNF alpha might be responsible for treatment failure.

Bionutrition and oral cancer in humans

Tobacco (smoking and smokeless) use and excessive consumption of alcohol are considered the main risk factors for oral cancer (ICD9 140-149). Conspicuous national and international variations in oral cancer incidence and mortality rates, as well as observations in migrant populations, raise the possibility that diet and nutritional status could be an important etiologic factor in oral carcinogenesis. As shown in this report, abuse of alcohol and tobacco has serious nutritional implications for the host, and generates increased production of reactive free radicals as well as eliciting immunosuppression. Maintenance of optimal competence of the immune system is critical for cancer surveillance. Active oxygen species and other reactive free radicals mediate phenotypic and genotypic alterations that lead from mutation to neoplasia. Consequently, the most widely used chemopreventive agents against oral cancer (e.g., vitamins A, E, C, and beta-carotene) are anti-oxidants/free radical scavengers. These anti-oxidants, both natural and synthetic, neutralize metabolic products (including reactive oxygen species), interfere with activation of procarcinogens, prevent binding of carcinogens to DNA, inhibit chromosome aberrations, restrain replication of the transformed cell, suppress actions of cancer promoters, and may even induce regression of precancerous oral lesions such as leukoplakia and erythroplakia. Malnutrition is characterized by marked tissue depletion of anti-oxidant nutrients, including GSH (gamma-glutamyl-cysteinyl-glycine), a key cellular anti-oxidant as well as a modulator of T-cell activation. GSH or its precursor cysteine inhibits activation of the nuclear transcription factor kB(NFkB), and has been shown to be protective against chemically induced oral cancer and leukoplakia. Alcohol-, tobacco-, and/or malnutrition-induced immunosuppression promotes impaired salivary gland function and oral mucosal immunity, a prominent reduction in the number of helper CD4 cells with less marked changes in number of suppressor T-cells, and depressed NK cell activity, among others. These suggest a breakdown in capacity or the malnourished to mount effective tumor surveillance. This review article underscores the compounding but important roles of nutritional/dietary factors in the long-established causal link between abuse of alcohol and tobacco (smoking and smokeless) and oral cancer.

Allogeneic bone marrow transplantation in patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent an acquired group of clonal disorders of the pleuripotent stem cells, resulting in progressive life-threatening cytopenias or transformation into acute leukemias. A major issue of using alloBMT in MDS is the criteria used for patient selection. Therapeutic trials of lesser intensity such as differentiating agents, and cytokines could be the preferable choice for patients with good prognostic features. On the other hand, patients with poor prognostic features may urgently need to establish a normal hematopoiesis through allogeneic bone marrow transplantation (alloBMT). Important prognostic indicators in MDS include FAB classification, presence of abnormal localization of immature precursors, degree of cytopenias and cytogenetic abnormalities. We used a novel preparative regimen--"BAC" consisting of the consecutive administration of 1 mg/kg of busulfan every 6 hours for 16 doses followed by 2 g/M2 of cytosine arabinoside (ara-C) given every 12 hours for four doses, and finally 60 mg/kg of cyclophosphamide daily for 2 days. Thirty two patients transplanted had a median age of 33 years. Nine of the patients had either RA or RARS, 21 had RAEB or RAEB-T and 2 were unclassified MDS. Twenty two of our patients had chromosomal abnormalities while 10 had a normal karyotype analysis. Nine of the 32 patients had documented leukemic transformation and received induction therapy prior to BMT. The median time from diagnosis to BMT was 5.6 months, ranging from 1.3 to 30.2 months. Nineteen out of 32 patients are alive without disease, with a median follow up of 24 months. The actuarial event-free survival for the entire group is 52%. Two patients have relapsed with an actuarial relapse rate of 12%. Only significant favorable prognostic indicator for the event-free survival was in the recipient of a genotypically matched graft (76%) compared to recipients of a non-genotypic graft (23%) (p = 0.02). "BAC" is a unique preparative regimen for alloBMT in MDS with excellent results.

Differentiation therapy of myelodysplastic syndromes with retinoic acid

Clinical trials of differentiation therapy on MDS with retinoic acid are reviewed, and it is discussed whether the differentiation therapy with this drug has scientific relevance for MDS. 13-Cis retinoic acid (13-CRA) may have moderate effect on 20-30% of patients with MDS. In general, the responses are short and toxicity is significant. Since the responses may take at least three weeks and sometimes several months to occur, only patients with a relatively indolent clinical course of MDS would be suitable candidates for this therapy. However, a placebo-controlled prospective randomized study could not confirm the effectiveness of this retinoic acid on MDS. There are only a few clinical trials of all-trans retinoic acid (ATRA) for treatment of MDS. ATRA may have a moderate effect on MDS, but no such a remarkable effect shown on acute promyelocytic leukemia. A placebo-controlled randomized study as having been conducted in 13-CRA is definitely needed to confirm the effectiveness of ATRA on MDS.

Biology and chemoprevention of head and neck cancer

Head and neck cancer remains a common cause of mortality and morbidity in the United States and throughout the world. In spite of advances in the management of patients with advanced disease, overall survival in this group remains poor. Furthermore, although cancer mortality is lower in patients with early-stage disease, treatment results in significant morbidity, and these patients also face the risk of developing a second primary tumor. Chemoprevention is an innovative approach to decrease overall cancer morbidity and mortality using substances that are capable of preventing cancer progression. Head and neck cancer is an excellent model for chemoprevention, as its biology is consistent with the two concepts important for the development of chemoprevention strategies: field cancerization and multistep carcinogenesis. Several classes of compounds have been evaluated in chemoprevention trials. The most frequently studied agents, the retinoids, were found frequently to induce remissions in patients with oral leukoplakia. Furthermore, retinoids prevented progression to malignancy in one randomized maintenance study. Other agents, including beta-carotene and vitamin E, have been found also to have activity in the management of oral leukoplakia. However, the clinical role of chemopreventive agents in reducing cancer mortality remains to be defined. Two studies, one in head and neck cancer and one in lung cancer, have shown the ability of retinoids to prevent the development of second primary tumors. Current large randomized trials are defining the effectiveness of these agents in reducing the mortality of aerodigestive tract tumors in individuals at high risk.

New uses for old vitamins. The treatment of myelodysplastic disorders

The treatment of myelodysplastic disorders with vitamins A and D or derivatives and nutrients has been less than satisfactory. Combinations of vitamin D3 and 13-CRA with or without cytosine arabinoside appear to offer no advantage over any of the single agents alone. Until other vitamin D derivatives are developed that are effective but do not cause hypercalcemia, vitamin D3 cannot be recommended for the treatment of MDS. 13-CRA has been shown to be effective in some patients with MDS; however, it cannot be recommended as standard therapy because of the conflicting data cited above. Further clinical trials with 13-CRA perhaps in combination with vitamin E or colony-stimulating factors are clearly indicated for this disease for which we have no effective therapy.

Myelodysplastic syndromes. Pathogenesis, diagnosis and treatment

Our understanding of the biology of leukemia and myelodysplasia is still only partial. The diagnosis of myelodysplasia is often based on quantitative and qualitative findings in the peripheral blood and bone marrow. These findings are often shared by other disorders. There is a need for sensitive and inexpensive laboratory tests to determine clonality and karyotypic abnormalities in this disorder. Future classifications of these syndromes will need to be based on morphologic and biologic markers that are closely linked to disease progression, response to treatment, and survival. Our limited understanding of the pathogenesis of MDS decreases the specificity and effectiveness of our therapeutic interventions. Agents that are minimally toxic such as CRA, danazol, 1,25-dihydroxyvitamin D3, androgens, and pyridoxine are seldom useful. Antileukemic therapy and allogeneic bone marrow transplantation have a major role to play in patients younger than 45 years of age; in older patients these treatment modalities remain controversial because of their toxicity. Hematopoietic growth factors, used alone or in combination, may improve the quality of life and improve survival of patients with MDS. Growth factors may also decrease treatment-related mortality associated with chemotherapy and bone marrow transplantation and render these treatment modalities available for a higher percentage of patients. The development of more specific differentiating agents may permit hematopoietic differentiation while minimizing side effects.

Myelodysplastic syndromes (refractory anemia). A perspective of the biologic, clinical, and therapeutic issues

The myelodysplastic syndromes (MDS) are a diverse group of hematologic disorders that have an abnormality in differentiation of the hematopoietic stem cell resulting in varying degrees of peripheral blood cytopenias. The author reviews the hematologic and clinical aspects of MDS, summarizes the recent pertinent aspects of the advances in our understanding of the disease, and explores the current approaches in the new treatment programs.