5 WARNINGS AND PRECAUTIONS
5.1 Infusion Reactions
Infusion reactions, defined as symptoms occurring within 24hours of infusion and resolving within 48hours of the last infusion in that course, were reported in 70.5% (165/234) of Ontak-treated patients across 3clinical studies utilizing the approved doses and schedule. Serious infusion reactions were reported in 8.1% (19/234) of Ontak-treated patients. There have been post-marketing reports of infusion reactions resulting in death.

For patients completing at least 4courses of Ontak treatment in Study1 [see Clinical Studies (14.1)], the incidence of infusion reactions was lower in the 3rd and 4th cycles as compared to the 1st and 2nd cycles of Ontak.

Resuscitative equipment should be available during Ontak administration. Immediately stop and permanently discontinue Ontak for serious infusion reactions.

5.2 Capillary Leak Syndrome
Capillary leak syndrome was defined as the occurrence of at least 2 of the following 3symptoms (hypotension, edema, serum albumin <3.0g/dL) at any time during Ontak therapy. These symptoms were not required to occur simultaneously to be characterized as capillary leak syndrome. As defined, capillary leak syndrome was reported in 32.5% (76/234) of Ontak-treated patients. Among these 76patients with capillary leak syndrome, one-third required hospitalization or medical intervention to prevent hospitalization. There have been post-marketing reports of capillary leak syndrome resulting in death.

The onset of symptoms in patients with capillary leak syndrome may be delayed, occurring up to 2weeks following infusion. Symptoms may persist or worsen after the cessation of Ontak.

Regularly assess patients for weight gain, new onset or worsening edema, hypotension (including orthostatic changes) and monitor serum albumin levels prior to the initiation of each course of therapy and more often as clinically indicated. Withhold Ontak for serum albumin levels of less than 3.0g/dL [see Warnings and Precautions (5.5)].

5.3 Visual Loss
Loss of visual acuity, usually with loss of color vision, with or without retinal pigment mottling has been reported following administration of Ontak. Recovery was reported in some of the affected patients; however, most patients reported persistent visual impairment.

5.4 CD25 Tumor Expression and eva luation
Confirm that the patient's malignant cells express CD25 prior to administration of Ontak. A testing service for the assay of CD25 expression in tumor biopsy samples is available. For information on this service call 877-873-4724.

5.5 Laboratory Monitoring/Hypoalbuminemia
Monitor serum albumin levels prior to the initiation of each treatment course. Withhold administration of Ontak if serum albumin levels are less than 3.0g/dL [see Dosage and Administration (2.1) and Warnings and Precautions (5.2)].

6 ADVERSE REACTIONS
The following adverse reactions are discussed in greater detail in other sections of the label:

Infusion Reactions [see Warnings and Precautions (5.1)]
Capillary Leak Syndrome [see Warnings and Precautions (5.2)]
Visual Loss [see Warnings and Precautions (5.3)]
6.1 Clinical Studies Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rat