Weight-based dosing of Yttrium 90 ibritumomab tiuxetan in patients with relapsed or refractory B-cell non-Hodgkin lymphoma.

BACKGROUND: Ibritumomab tiuxetan radioimmunotherapy produces durable remissions in patients with relapsed/refractory indolent non-Hodgkin lymphoma. The dosing of Yttrium 90 (90Y)-ibritumomab tiuxetan is based on patient weight and platelet count: 0.4 mCi/kg in patients with a count >or= 150 x 10(9)/L, to a maximum dose of 32 mCi. Patients weighing > 80 kg with platelet counts of >or= 150 x 10(9)/L receive a lower dose per unit of body weight. We evaluated whether this influences the safety or efficacy of treatment. PATIENTS AND METHODS: Data on efficacy and safety in patients in 3 registration trials who were treated with 90Y ibritumomab tiuxetan at 0.4 mCi/kg (patients weighing 80 kg) were collected. RESULTS: Clinical responses were evaluated in 103 patients weighing 80 kg (median, 95 kg). Sex (41% female vs. 73% male) was the only significantly different characteristic between the patients weighing 80 kg, respectively. The overall response rates were 79% ( 80 kg), and the complete response rates were 28% and 34%, respectively. Median times to progression were 8.9 months ( 80 kg). There were no significant differences in efficacy measures or in the incidences of grade 3/4 nonhematologic adverse events, neutropenia, thrombocytopenia, or anemia. CONCLUSION: The dose of 90Y ibritumomab tiuxetan was < 0.4 mCi/kg in 39% of patients, owing to the 32-mCi dose cap, but the efficacy or safety of 90Y ibritumomab tiuxetan in patients > 80 kg was not affected.

Verbal memory retrieval deficits associated with untreated hypothyroidism.

The effects of inadequate thyroid hormone availability to the brain on adult cognitive function are poorly understood. This study assessed the effects of hypothyroidism on cognitive function using a standard neuropsychological battery in 14 patients suffering from untreated hypothyroidism and complaining of subjective cognitive difficulties in comparison with 10 age-matched healthy comparison subjects. Significant differences between groups were limited to verbal memory retrieval as measured by the California Verbal Learning Test (CVLT). On short delay free recall, long delay free recall, and long delay cued recall, significant differences remained between groups despite the limited statistical power of this study. There were no significant results found between groups on attentional or nonverbal tasks. Results suggest that hypothyroid-related memory deficits are not attributable to an attentional deficit but rather to specific retrieval deficits.

Memory improvement with treatment of hypothyroidism.

The consequences of inadequate thyroid hormone availability to the brain and treatment effects of levothyroxine on cognitive function are still poorly understood. This study prospectively assessed the effects of thyroid replacement therapy on cognitive function in patients suffering from biochemical evidenced, untreated hypothyroidism. Significant effects between the untreated hypothyroid group and control group were limited to verbal memory retrieval. When assessing the effects of 3-month treatment, results revealed that the treated hypothyroid group had significant increased verbal memory retrieval. Results suggest that specific memory retrieval deficits associated with hypothyroidism can resolve after replacement therapy with levothyroxine.