Bortezomib (formerly PS-341), a promising new drug for the treatment of multiple myeloma, recently received accelerated approval from the U.S. Food and Drug Administration (FDA) for the therapy of patients with progressive myeloma after previous treatment. Two phase II studies of bortezomib used the same schedule of twice-weekly i.v. dosing for the first 2 weeks of each 3-week cycle. In a randomized study of 54 patients, two doses were compared (1.0 and 1.3 mg/m 2 ) and objective responses occurred at both dose levels (23% versus 35%), including one complete response in each arm. In the other phase II study, 202 heavily pretreated patients (median of six prior therapies) all received the same schedule at 1.3 mg/m 2 . Of 188 evaluable patients, complete responses occurred in five (3%) and partial responses occurred in 47 (25%). The median duration of response was 365 days. The most clinically relevant adverse events were asthenic conditions, nausea, vomiting, diarrhea, thrombocytopenia, and a peripheral neuropathy that often was painful. This report highlights the FDA analysis supporting the accelerated approval. The Oncologist 2003;8:508-513 The Oncologist 2003;8:508-513 www.TheOncologist.comCorrespondence: Robert C. Kane, M.D., F.A.C.P., U.S. FDA, HFD-150, 5600 Fishers Lane, Rockville, Maryland 20857, USA. Telephone: 301-594-2473; Fax: 301-594-0499; e-mail kaner@cder.fda.gov Received September 18, 2003; accepted for publication October 14, 2003. ©AlphaMed Press 1083-7159/2003 The Oncologist ® FDA Commentary LEARNING OBJECTIVESAfter completing this course, the reader will be able to:1. Discuss the rationale and requirements for accelerated cancer drug approval by the U.S. Food and Drug Administration (FDA). 4. Explain the mechanism of action of bortezomib and its role in cancer treatment.Access and take the CME test online and receive one hour of AMA PRA category 1 credit at CME.TheOncologist.com CME CME This material is protected by U.S. Copyright law.Unauthorized reproduction is prohibited. (Millenium Pharmaceuticals, Inc.; Cambridge, MA), for use as a single agent for the treatment of patients with multiple myeloma after two prior therapies and progressing on their most recent therapy. In 1998, Millennium Pharmaceuticals, Inc., submitted an Investigational New Drug Application for bortezomib and in January, 2003, a New Drug Application (NDA) was filed. At the time of the NDA submission, melphalan, cyclophosphamide, and carmustine had been FDA approved for myeloma treatment, and pamidronate and zoledronate were approved for reducing skeletal-related events. This commentary reports on the supporting data, the review process, and the standards of evidence employed in the approval of bortezomib.

The dose finding study of 54 patients showed a higher response rate for patients given 1.3 mg/m 2 compared with 1.0 mg/m 2 twice weekly for two of the 3-week schedule, but the study was too small for statistical dose-response comparisons. The most commonly reported adverse events were asthenic conditions (including fatigue, malaise, and weakness) in 65%, nausea (64%), diarrhea (51%), appetite decreased (including anorexia; 43%), constipation (43%), thrombocytopenia (43%), peripheral neuropathy (37%, including peripheral sensory neuropathy and peripheral neuropathy aggravated), pyrexia (36%), vomiting (36%), and anemia (32%).Conclusions: The FDA granted marketing approval to Millennium Pharmaceuticals on May 13, 2003 for bortezomib for use as a single agent for the treatment of multiple myeloma in patients who have received at least two prior therapies and have demonstrated disease progression on the last therapy. Accelerated approval was based on a surrogate end point of response rate rather than clinical benefit, such as an improvement in survival. The recommended dose of bortezomib is 1.3 mg/m 2 administered twice weekly for 2 weeks (days 1, 4, 8, and 11) followed by a 10-day rest period (days 12-21). Accelerated approval was based on the results of two Phase II studies in a total of 256 patients and additional Phase I safety information. Mandated Phase IV study commitments to characterize clinical efficacy and safety more precisely are discussed.

Patients with hormone-sensitive breast cancer who have responded to tamoxifen may receive additional benefit from a second endocrine agent following progression or relapse after tamoxifen therapy. Fulvestrant (Faslodex ® , ICI 182780, AstraZeneca Pharmaceuticals; Wilmington, Delaware) is a selective antagonist of estrogen designed to have no estrogenic effects. Lack of aqueous solubility led to the development of a parenteral formulation for monthly intramuscular administration. Fulvestrant has been shown to inhibit the proliferative effects of estrogen on sensitive tissues in vitro and in vivo, and is without apparent measurable estrogenic activity. The data upon which marketing approval for fulvestrant was based are summarized below. Eight hundred fifty-one postmenopausal women with advanced breast cancer were enrolled in two phase III studies, 400 in a North American double-blind study and 451 in a European open-label study, comparing the efficacy and safety of fulvestrant with anastrozole. Four hundred twenty-eight patients were randomized to receive fulvestrant 250 mg monthly by intramuscular injection and 423 patients were to receive anastrozole 1 mg daily. Patients were considered hormone sensitive either by receptor status or previous response to endocrine therapy. Over 96% of patients had previously