Breakthrough Therapies Highlight Week in Cancer News
Recent advances and updates in oncology and cancer drug development.
FDA Expands Palbociclib Approval
The FDA approved palbociclib for use in combination with fulvestrant in pretreated patients with HR-positive, HER2-negative metastatic breast cancer. The approval is based on findings from the phase III PALOMA-3 trial, in which adding palbociclib to standard fulvestrant more than doubled progression-free survival in pretreated patients with HR-positive, HER2-negative breast cancer.
Palbociclib delayed disease progression by almost 5 months. Median PFS was 9.5 months with the palbociclib combination versus 4.6 months in the placebo arm (HR, 0.461; P <.0001). The PFS benefit was observed regardless of menopause status and remained consistent across all prespecified patient subgroups. OS data are not yet mature.
The overall response rate was 24.6% for the palbociclib arm compared with 10.9% for the placebo plus fulvestrant arm. The duration of response was 9.3 months versus 7.6 months, respectively.
FDA Grants Midostaurin Breakthrough Designation for AML
The FDA granted midostaurin a breakthrough therapy designation as a potential treatment for adult patients with newly diagnosed FLT3-mutated acute myeloid leukemia. In the phase III RATIFY trial, which was the basis for the designation, the addition of midostaurin to standard chemotherapy reduced the risk of death by 23% compared with chemotherapy alone.
After censoring for patients who received stem cell transplants, the overall survival benefit with midostaurin remained steady at 25%. Novartis plans to submit data from the study to the FDA within the first half of 2016. In the uncensored data, median OS was 74.7 months with midostaurin versus 25.6 months with chemotherapy alone (HR, 0.77; P = .0074). Median OS data were not obtained in the censored population.
Overall, the 4-year censored OS rate with midostaurin was 63.8% versus 55.7% for placebo (HR, 0.75; P = .04). In those censored for transplant, median EFS with midostaurin was 8.2 versus 3.0 months with placebo (HR, 0.84; P = .025).
Durvalumab Granted Breakthrough Status for Bladder Cancer
The FDA has granted a breakthrough therapy designation to durvalumab as a treatment for patients with PD-L1—positive inoperable or metastatic urothelial bladder cancer following progression on prior treatment with a platinum-based regimen. The breakthrough designation, which is meant to expedite the development of therapies that offer substantial benefits over existing options, was based on early findings from a phase I study that explored the immunotherapy across several solid tumors.
Findings from the urothelial bladder cancer arm of the large trial have not yet been released; however, data from the study were submitted for presentation at a future medical meeting, according to AstraZeneca. The phase III DANUBE study, which launched in July 2015, is currently comparing frontline durvalumab monotherapy against durvalumab plus the CTLA-4 inhibitor tremelimumab or standard of care chemotherapy for patients with metastatic bladder cancer.
The primary endpoint of the study, which hopes to enroll 525 participants, is progression-free survival. The estimated primary completion date is November 2017.
Head and Neck Cancer Roundup
A number of interesting studies were presented at the 2016 Multidisciplinary Head and Neck Cancer Symposium took place recently in Arizona. In the first trial, several biomarkers were associated with progression-free survival and overall survival for patients treated with second-line afatinib for recurrent or metastatic head and neck squamous cell carcinoma.
Afatinib improved PFS compared with methotrexate in patients with tumors that were p16-negative, EGFR amplified, HER3-low, or PTEN-high. OS was improved with afatinib versus methotrexate when EGFR amplified and PTEN expression was high.
In another study presented at the meeting, adding cetuximab to induction chemotherapy and hyperfractionated or accelerated chemoradiation therapy produced long-term disease control in patients with HPV-negative, locoregionally advanced head and neck squamous cell carcinoma.
A third study at the meeting found that tobacco-associated mutations accumulate over time in smokers with HPV-positive oropharyngeal squamous cell cancer, and that the number of HPV viral reads was inversely associated with smoking and survival status. These findings suggest that HPV-positive tumors will eventually behave like HPV-negative tumors, which have a worse prognosis.
Expert Perspective on Immuno-Oncology in Head & Neck Cancer
OncLive interviewed two leading experts in the field of immunotherapy at the 2016 Multidisciplinary Head and Neck Cancer Symposium. In the first interview, Tanguy Y. Seiwert, MD, said that he expects both nivolumab and pembrolizumab to gain approval for patients with head and neck cancer in 2016. To date, a phase III study for nivolumab has completed and 2 phase III studies for pembrolizumab are in progress.
Robert Ferris, MD, PhD, the lead investigator of the phase III nivolumab trial, noted that immunotherapy would be the fourth modality for patients with head and neck cancer. He noted that CheckMate-141, which explored nivolumab, was the first study in head and neck cancer to show a survival improvement in more than 10 years, which is a significant milestone.
Following the demonstration of success for immunotherapy, Ferris expects these agents to move forward in the treatment landscape to the frontline and adjuvant setting.