title: Progression-Free Survival Among Patients With Well-Differentiated or Dedifferentiated Liposarcoma Treated With CDK4 Inhibitor Palbociclib: A Phase 2 Clinical Trial.
abstract: OBJECTIVE
  More than 90% of well-differentiated or dedifferentiated liposarcomas (WD/DDLS) have CDK4 amplification. The selective CDK4 and CDK6 inhibitor palbociclib inhibits growth and induces senescence in liposarcoma cell lines and xenografts. Our prior phase 2 study demonstrated that treatment with palbociclib (200 mg daily for 14 days every 21 days) resulted in clinical benefit in WD/DDLS but moderate hematologic toxic effects. It is important to understand whether palbociclib at a new dose and schedule-125 mg daily for 21 days every 28 days-results in clinical benefit and manageable toxic effects.
  
  
  OBJECTIVE
  To determine the progression-free survival (PFS) at 12 weeks of patients with WD/DDLS treated with palbociclib (PD0332991).
  
  
  METHODS
  In this phase 2, nonrandomized, open-label clinical trial conducted at the Memorial Sloan Kettering Cancer Center, 60 patients 18 years and older with advanced WD/DDLS and measurable disease by RECIST 1.1 were enrolled from December 2011 to January 2014 and followed to March 2015. Patients received oral palbociclib at 125 mg daily for 21 days in 28-day cycles.
  
  
  METHODS
  Primary end point was PFS. Secondary end points included response rate and toxic effects.
  
  
  RESULTS
  Overall, 30 patients were enrolled in the initial cohort and 30 more in an expansion cohort. Median (range) age was 61.5 (35-87) years; 31 patients (52%) were male; median (range) Eastern Cooperative Oncology Group score was 0 (0-1). Progression-free survival at 12 weeks was 57.2% (2-sided 95% CI, 42.4%-68.8%), and the median PFS was 17.9 weeks (2-sided 95% CI, 11.9-24.0 weeks). There was 1 complete response. Toxic effects were primarily hematologic and included neutropenia (grade 3, n = 20 [33%]; grade 4, n = 2 [3%]) but no neutropenic fever.
  
  
  CONCLUSIONS
  In patients with advanced WD/DDLS, treatment with palbociclib was associated with a favorable PFS and occasional tumor response. This dose and schedule appears active and may have less toxic effects than 200 mg for 14 days.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT01209598.
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Dickson
authors.affiliation: Columbia University Medical Center, New York, New York.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Schwartz
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Mary Louise
authors.initials: ML
authors.lastname: Keohan
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Sandra P
authors.initials: SP
authors.lastname: D'Angelo
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Mrinal M
authors.initials: MM
authors.lastname: Gounder
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Ping
authors.initials: P
authors.lastname: Chi
authors.affiliation: Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Antonescu
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Landa
authors.affiliation: Department of Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Li-Xuan
authors.initials: LX
authors.lastname: Qin
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Aimee M
authors.initials: AM
authors.lastname: Crago
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: Samuel
authors.initials: S
authors.lastname: Singer
authors.affiliation: Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Andrew
authors.initials: A
authors.lastname: Koff
authors.affiliation: Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York8Weill Cornell Medical College, New York, New York.
authors.forename: William D
authors.initials: WD
authors.lastname: Tap
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051358:Cyclin-Dependent Kinase 4 / Q000037:antagonists & inhibitors; D051361:Cyclin-Dependent Kinase 6 / Q000037:antagonists & inhibitors; D018572:Disease-Free Survival; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008080:Liposarcoma / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000008:administration & dosage* / Q000009:adverse effects; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D011725:Pyridines / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; C500026:palbociclib