FDA Update

FDA Approves Imaging Agent that Helps Detect Prostate Cancer

The Food and Drug Administration (FDA) has approved the production and use of Choline C 11 Injection, an imaging agent used with positron emission tomography (PET) scans to help detect prostate cancer that has returned.

Choline C 11 Injection is administered intravenously to produce an image that helps to identify specific body sites for follow-up tissue sampling and testing in men whose prostate-specific antigen (PSA) levels have risen after earlier prostate cancer treatment.

The imaging agent must be made in a specialized facility and used shortly after its production. The Mayo Clinic is now the first FDA-approved facility to produce Choline C 11 Injection.

The safety and effectiveness of the imaging agent were verified by four independent studies. The studies examined a total of 98 patients with elevated PSA levels but no sign of recurrent prostate cancer with conventional imaging.

In each of the four studies, recurrent prostate cancer was confirmed by tissue sampling in at least half of the men who had abnormalities detected on PET scans with Choline C 11 imaging. PET scan errors were also reported. Depending on the study, false-positive PET scans were observed in 15 to 47 percent of the men. These findings underscore the need to confirm findings with tissue samples when abnormalities are detected with Choline C 11 Injection PET scans, the FDA noted in a press release.

Aside from a mild skin reaction at the injection site, no side effects to Choline C 11 Injection were reported.

Drug for Advanced Prostate Cancer Approved

The Food and Drug Administration (FDA) has approved enzalutamide (Xtandi) to treat men with advanced prostate cancer that has spread or recurred after medical or surgical therapy to minimize testosterone, which fuels tumor growth. The drug was approved for use in prostate cancer patients previously treated with docetaxel.

The safety and effectiveness of enzalutamide—previously called MDV3100—was evaluated in a study of 1,199 patients with metastatic castration-resistant prostate cancer who had received prior treatment with docetaxel. The median overall survival for patients who received enzalutamide was 18.4 months, compared with 13.6 months for those who received a placebo.

The most common side effects were fatigue, back pain, diarrhea, joint pain, hot flush, tissue swelling, musculoskeletal pain, respiratory infections, dizziness, spinal cord compression, blood in urine, tingling sensation, anxiety, and high blood pressure.

Seizures occurred in about 1 percent of those receiving enzalutamide. Study participants who had a seizure stopped enzalutamide therapy. The clinical study excluded men who had a history of seizure or several other brain conditions or who were taking medications that may cause seizures. The safety of enzalutamide in patients with these conditions is unknown.

Enzalutamide was reviewed under the FDA’s priority review program, which allows an expedited 6-month review for drugs that may offer major advances in treatment or that provide a treatment when no adequate therapy exists.

FDA Approves New Drug to Treat Chronic Myelogenous Leukemia

The Food and Drug Administration has approved bosutinib (Bosulif) to treat chronic myelogenous leukemia (CML), a blood and bone marrow disease that usually affects older adults. Bosutinib is intended for patients with chronic, accelerated, or blast phase Philadelphia chromosome-positive CML who are resistant to or who cannot tolerate other therapies, including imatinib (Gleevec).

Most people with CML have a chromosomal aberration called the Philadelphia chromosome, which causes the bone marrow to make an abnormal tyrosine kinase enzyme called Bcr-Abl. This enzyme promotes the proliferation of abnormal and unhealthy infection-fighting white blood cells called granulocytes. Bosutinib is a tyrosine kinase inhibitor (TKI) that works by blocking Bcr-Abl signaling.

Bosutinib’s safety and effectiveness were evaluated in a clinical trial involving 546 adults with chronic, accelerated, or blast phase CML. All of the patients had been previously treated with at least one TKI, either imatinib or imatinib followed by dasatinib (Sprycel) and/or nilotinib (Tasigna).

Among patients with chronic phase CML, 34 percent of patients who had been treated previously with imatinib and 27 percent of those who received more than one prior TKI achieved a major cytogenetic response within 24 weeks. 

Among patients with accelerated phase CML who had received at least one prior TKI, 30 percent had their blood counts return to the normal range (a complete hematologic response) by week 48, and 55 percent achieved a complete hematologic response, no evidence of leukemia, or return to chronic phase (an overall hematologic response) by week 48. Among patients with blast phase CML who had received at least one prior TKI, 15 percent had a complete hematologic response and 28 percent an overall hematologic response by week 48.

The most common side effects observed in those receiving bosutinib were diarrhea, nausea, a low level of platelets in the blood, vomiting, abdominal pain, rash, anemia, fever, and fatigue.