Study of Iodine 131 Anti B1 Antibody for 1st or 2nd Relapsed Indolent B-Cell Lymphomas or B-Cell Lymphomas That Have Transformed to a More Aggressive Histology

Par. with response include those with Complete Response (CR: complete resolution of all disease-related radiological abnormalities and the disappearance of all signs and symptoms related to the disease), Clinical Complete Response (CCR: complete resolution of all disease-related symptoms; residual foci, thought to be residual scar tissue, are present), or Partial Response (PR: >=50% reduction in the sum of the products of the longest perpendicular diameters of all measurable lesions; no new lesions).

Responses had to be confirmed by 2 separate evaluations occurring >=4 weeks apart. Par. with confirmed response include those with Complete Response (CR: complete resolution of all disease-related radiological abnormalities and the disappearance of all signs and symptoms related to the disease), Clinical Complete Response (CCR: complete resolution of all disease-related symptoms; residual foci, thought to be residual scar tissue, are present), or Partial Response (PR: >=50% reduction in the sum of the products of the longest perpendicular diameters of all measurable lesions; no new lesions).

Responses had to be confirmed by 2 separate evaluations occurring >=4 weeks apart. CR is defined as the complete resolution of all disease-related radiological abnormalities and the disappearance of all signs and symptoms related to the disease.

Responses had to be confirmed by 2 separate evaluations occurring >4 weeks apart. CCR is defined as the complete resolution of all disease-related symptoms; residual foci, thought to be residual scar tissue, are present. Generally, an unchanging lesion =<2 centimeters (cm) in diameter by radiographic evaluation or =<1 cm in diameter by physical examination can be considered scar tissue. The extent of disease (EOD) must be unchanged or decreased upon follow-up evaluations. If the EOD was unchanged or if further decreases occurred for >=6 months, the participant was reclassified as having a CR.

Responses had to be confirmed by 2 separate evaluations occurring >=4 weeks apart. Confirmed PR is defined as a >=50% reduction in the sum of the products of the longest perpendicular diameters of all measurable lesions, with no new lesions.

Responses had to be confirmed by 2 separate evaluations occurring >=4 weeks apart. Duration of response is defined as the time from the first documented response until disease progression. Disease progression is defined as a >=25% increase from the nadir value of the sum of the products of the longest perpendicular diameters of all measurable lesions or the appearance of any new lesion. Individual lesions must be >2 cm in diameter by radiographic evaluation or >1 cm in diameter by physical examination.

Time to progression or progression-free survival is defined as the time from the dosimetric dose to the first documented occurrence of disease progression or death. Disease progression is defined as a >=25% increase from the nadir value of the sum of the products of the longest perpendicular diameters of all measurable lesions or the appearance of any new lesion. New lesions must be greater than 2 x 2 centimeters (cm) in diameter by radiographic evaluation or greater than 1 cm in diameter by physical examination.

Time to treatment failure is defined as the length of time from the date of enrollment to the first incidence of treatment withdrawal, study removal, progression, and/or alternative therapy for the participant's lymphoma, or death.

Overall survival is defined as the time from the treatment start date to the date of death from any cause.

An AE is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment. The Investigator assessed whether the AE was possibly or probably related to study drug. In addition, all laboratory-derived hematologic toxicities were assumed to be possibly or probably related to study drug.

An SAE is any event occurring at any dose that results in any of the following: death, a life-threatening adverse drug experience (ADE; at immediate risk of death from the experience as it occurred), inpatient hospitalization/prolongation of existing hospitalization, a persistent/significant disability/incapacity, or a congenital anomaly/birth defect. Medical events that may not result in death, be life-threatening, or require hospitalization may be considered to be a serious ADEs when based upon appropriate medical judgment. Relatedness was based on the Investigator's medical judgement.

An infection is the colonization of a host organism by a parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease. Specimen samples of the body fluid are cultured for testing whether the infectious organism is present and grown in the culture media to assess the growth pattern of the organisms present in the specimen. The culture results could be positive or negative. The positive culture results indicate that the tested participant has the infection under investigation, in which case therapeutic treatment with anti-infective is required.

Anti-infectives are capable of acting against infection, by inhibiting the spread of an infectious agent or by killing the infectious agent outright. Anti-infective is a general term that encompasses antibacterials, antibiotics, antifungals, antiprotozoans, and antivirals.

Adverse events were graded using the Common Toxicity Criteria from the Cancer Therapy Evaluation Program, Division of Cancer Therapy, National Cancer Institute. Grades: 0 = No adverse event or within normal limits; 1 = Mild adverse event; 2 = Moderate adverse event; 3 = Severe and undesirable adverse event; 4 = Life-threatening or disabling adverse event; 5 = Death related to adverse event.

Nadir is defined as the lowest laboratory value recorded following the administration of the study medication. Time to recovery to baseline in hematologic laboratory evaluations is the time required for recovery from nadir values to baseline values.

Nadir is defined as the lowest laboratory value recorded following the administration of study medication. ANC is a measure of the number of neutrophil granulocytes present in the blood. Neutrophils are a type of WBC that fights against infection. Platelets and WBCs are types of blood cells.

Nadir is defined as the lowest laboratory value recorded following the administration of study medication. Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells.

Tositumomab is a murine (mouse) antibody. Participants in this study were evaluated to determine if they developed a human anti-murine antibody (HAMA) immune response after administration of tositumomab and iodine I 131 tositumomab.

Time to HAMA positivity is defined as the time from the first dosimetric dose to the first reported HAMA-positive result for the participant.

Hypothyroidism, a condition in which the thyroid gland does not produce enough thyroid hormone (resulting in the elevation of thyroid stimulating hormone [TSH] in the blood), may result from treatment with radioactive iodine I 131. A thyroid blockade medication was given prior to administration of the study drug and up to 2 weeks after the therapeutic dose to prevent the uptake of I 131 in the thyroid gland. Thyroid function was determined periodically, including during follow-up, in order to assess if there was any effect of the I 131 on thyroid function, such as hypothyroidism.

Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone (resulting in the elevation of thyroid stimulating hormone [TSH] in the blood).