Treatment recommendations in Waldenstrom's macroglobulinemia: consensus panel recommendations from the Second International Workshop on Waldenstrom's Macroglobulinemia

This presentation represents consensus recommendations for the treatment of patients with Waldenstrom's macroglobulinemia (WM), which were prepared in conjunction with the second International Workshop held in Athens, Greece during September 2002. The faculty adopted the following statements for the management of patients with Waldenstrom's macroglobulinemia: (1) Alkylating agents, nucleoside analogues, and rituximab are reasonable choices for first line therapy of WM. (2) Both cladribine and fludarabine are reasonable choices for the therapy of WM. (3) Combinations of alkylating agents, nucleoside analogues, or rituximab should at this time be encouraged in the context of a clinical trial. (4) In WM, rituximab can cause a sudden rise in serum IgM and viscosity levels in certain patients, which may lead to complications, therefore close monitoring of these parameters and symptoms of hyperviscosity is recommended for WM patients undergoing rituximab therapy. (5) For relapsed disease, it is reasonable to use an alternate first line agent or re-use of the same agent; however, since autologous stem cell transplantation may have a role in treating patients with relapsed disease it is recommended that for patients in whom autologous transplantation is seriously being considered, exposure to alkylator or nucleoside analogue drugs should be limited. (6) Combination chemotherapy for patients who can tolerate myelotoxic therapy, thalidomide alone or with dexamethasone, can reasonably be considered to have relapsed. (7) Autologous stem cell transplantation may be considered for patients with refractory or relapsing disease. (8) Allogeneic transplantation should only be undertaken in the context of a clinical trial. (9) Plasmapheresis should be considered as interim therapy until definitive therapy can be initiated. (10) Rituximab should be considered for patients with IgM-related neuropathies. (11) Corticosteroids may be useful in the treatment of symptomatic mixed cryoglobulinemia. (12) Splenectomy is rarely indicated but has been used to manage painful splenomegaly and hypersplenism.

Vitiligo associated with cutaneous amyloidosis

Vitiligo is known to be associated with a variety of dermatoses and systemic diseases. We describe a case of vitiligo developing in a patient having cutaneous amyloidosis. To our knowledge this is the first report of its kind in the literature.

Oral condylomata acuminata

A case of oral condylomata acuminata in a boy aged 14 years is reported for its uncommon presentation, which warrants a high index of suspicion for diagnosis.

Enhanced platelet aggregation, high homocysteine level, and microvascular disease in diabetic muscle infarctions: implications for therapy

Muscle infarction is a rare complication in patients with diabetes mellitus, probably because of the rich vascular supply of this tissue. We describe a patient with type 1 diabetes who had infarction of the muscles in her right thigh. We report, for the first time, that the patient, in addition to an advanced microvascular disease in the muscle, had increased plasma total homocysteine levels and increased platelet aggregation. These pathologies might have a synergistic effect on the development of this rare complication and should be treated aggressively to prevent further episodes.

Comparison of once-daily versus pharmacokinetic dosing of aminoglycosides in elderly patients

PURPOSE

Once-daily dosing has been suggested as an alternative method of dosing aminoglycosides that would reduce their toxicity while maintaining efficacy. There have been no studies published to date comparing once-daily dosing and pharmacokinetic dosing of aminoglycosides. We conducted a randomized controlled trial comparing the safety and effectiveness of 4 mg/kg IV once-daily dosing of gentamicin or tobramycin with a pharmacokinetic dosing method using an initial dose of 2 mg/kg IV every 12 hours.

PATIENTS AND METHODS

Ninety-six patients were randomly assigned to either the once-daily dosing group (4 mg/kg) or the pharmacokinetic dosing group (initial dose of 2 mg/kg every 12 hours). In the once-daily dosing group, the dosing interval was extended by 12 to 24 hours to maintain a serum trough concentration < 1.5 mg/L regardless of the peak concentration. Dosing in the other group was adjusted based on the individual pharmacokinetic data to achieve a serum peak concentration of 6 to 10 mg/L and a trough concentration below 1.5 mg/L. The patients studied were predominantly elderly males (mean age 69 years). All patients were assessed for treatment efficacy and nephrotoxicity.

RESULTS

There was no significant difference between the two groups with regard to clinical and bacteriologic efficacy. Incidence of nephrotoxicity was 24% in the once-daily group and 14% in the pharmacokinetic dosing group but the difference was not statistically significant (P = 0.13). Unlike previous studies, we found a correlation between high serum peak concentration and incidence of nephrotoxicity in the once-daily dosing group. Nephrotoxicity developed in six out of 10 patients (60%) with an initial serum peak concentration greater than 12.0 mg/L compared to two out of 24 patients (8.3%) with an initial peak concentration less than 12.0 mg/L (P < 0.001) in the once-daily group. Serum peak concentrations in the pharmacokinetic dosing group were not correlated with nephrotoxicity.

CONCLUSIONS

Once-daily dosing and pharmacokinetic dosing of aminoglycosides appear to have equal efficacy and toxicity. However, in the elderly population, high serum peak concentrations that occur with once-daily aminoglycoside dosing may increase the risk of nephrotoxicity.

Effects of estradiol and progesterone on platelet calcium responses

We investigated the effects of 17 beta-estradiol (beta E2), alpha-estradiol (alpha E2), and progesterone (P) on baseline and vasopressin (AVP)-induced [Ca2+]i in human platelets obtained from healthy male and female volunteers. Platelets were treated with beta E2, alpha E2, P, or ethanol vehicle for 30 min at 37 degrees C. In males, both beta E2 and P at 10(-5) mol/L reduced the AVP-induced rise in [Ca2+]i, to 72 +/- 3% (mean +/- SEM) and 53 +/- 3%, respectively. However, at 10(-6) mol/L only beta E2 had a significant effect (P < .02). In females, 10(-6) and 10(-5) beta E2 reduced the AVP response to 85.3 +/- 4.6% and 80.8 +/- 5.4% of control values, respectively. Progesterone (10(-6) and 10(-5) mol/L) reduced the AVP response to 83.8 +/- 5.1% and 60.3 +/- 2.0% of control values, respectively. The inactive estrogen alpha E2 had no effect on basal or AVP-induced rise in [Ca2+]i in either subject population, suggesting hormonal specificity. Neither beta E2 nor P affected baseline [Ca2+]i in either population. Thus, by attenuating [Ca2+]i responses in platelets, beta E2 and P may modulate platelet aggregation and atherosclerosis.