Pfizer Announces Overall Survival Results from Phase 3 PALOMA-3 Trial of IBRANCE® (Palbociclib) in HR+, HER2- Metastatic Breast Cancer

On June 25, 2018 Pfizer reported overall survival (OS) results from the Phase 3 PALOMA-3 trial, which evaluated IBRANCE (palbociclib) in combination with fulvestrant compared to placebo plus fulvestrant in women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer whose disease has progressed after prior endocrine therapy (Press release, Pfizer, JUN 25, 2018, View Source [SID1234527458]). The results demonstrated a positive trend in the hazard ratio favoring the IBRANCE combination, although this trend did not reach statistical significance. Overall survival is a secondary endpoint of the PALOMA-3 trial and, as such, the trial design was not optimized to detect a statistically significant difference in OS.

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"While the difference in overall survival narrowly missed the threshold for statistical significance – a high bar for any trial in this patient population – it is similar, in absolute terms, to the improvement in median progression-free survival previously demonstrated in this trial.1 We are encouraged by these results, which build on the compelling clinical benefit delivered by IBRANCE," said Mace Rothenberg, M.D., chief development officer, Oncology, Pfizer Global Product Development. "IBRANCE in combination with endocrine therapy has transformed the treatment landscape for patients with HR+, HER2- metastatic breast cancer."

PALOMA-3 met its primary endpoint of progression-free survival (PFS) at interim analysis and results were published in The New England Journal of Medicine in June 2015; updated PFS data were later presented at the 2016 San Antonio Breast Cancer Symposium. The trial demonstrated a statistically significant and clinically meaningful improvement in PFS for IBRANCE plus fulvestrant compared to placebo plus fulvestrant. PFS is a well-established measure of clinical benefit in metastatic breast cancer trials.2 IBRANCE in combination with fulvestrant has been approved in more than 80 countries around the world based on the PFS demonstrated in PALOMA-3.

"The duration of the survival in hormone receptor-positive metastatic breast cancer patients, and the potential for subsequent therapies to confound overall survival outcomes, make demonstrating statistically significant improvement in overall survival extremely difficult," said Nicholas Turner, M.D., Ph.D., professor of molecular oncology at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, as well as principal investigator of the PALOMA-3 trial. "The results from this overall survival analysis support the strong progression-free survival results from PALOMA-3 and, while not statistically significant, are encouraging for physicians and patients. We look forward to presenting the detailed data at an upcoming medical meeting."

The most common adverse reactions in PALOMA-3 included neutropenia, leukopenia, infections, fatigue and nausea; no new safety signals were identified as part of this final OS analysis.

IBRANCE in combination with endocrine therapy is a standard of care for HR+, HER2- metastatic breast cancer. IBRANCE has been prescribed to more than 120,000 patients globally to date.

The full prescribing information for IBRANCE can be found at www.pfizer.com.

About IBRANCE (palbociclib) 125 mg capsules

IBRANCE is an oral inhibitor of CDKs 4 and 6,3 which are key regulators of the cell cycle that trigger cellular progression.4,5 In the U.S., IBRANCE is indicated for the treatment of HR+, HER2- advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine based therapy in postmenopausal women, or fulvestrant in women with disease progression following endocrine therapy.

IMPORTANT IBRANCE (palbociclib) SAFETY INFORMATION FROM THE U.S. PRESCRIBING INFORMATION

Neutropenia was the most frequently reported adverse reaction in PALOMA-2 (80%) and PALOMA-3 (83%). In PALOMA-2, Grade 3 (56%) or 4 (10%) decreased neutrophil counts were reported in patients receiving IBRANCE plus letrozole. In PALOMA-3, Grade 3 (55%) or Grade 4 (11%) decreased neutrophil counts were reported in patients receiving IBRANCE plus fulvestrant. Febrile neutropenia has been reported in 1.8% of patients exposed to IBRANCE across PALOMA-2 and PALOMA-3. One death due to neutropenic sepsis was observed in PALOMA-3. Inform patients to promptly report any fever.

Monitor complete blood count prior to starting IBRANCE, at the beginning of each cycle, on Day 15 of first 2 cycles and as clinically indicated. Dose interruption, dose reduction, or delay in starting treatment cycles is recommended for patients who develop Grade 3 or 4 neutropenia.

Based on the mechanism of action, IBRANCE can cause fetal harm. Advise females of reproductive potential to use effective contraception during IBRANCE treatment and for at least 3 weeks after the last dose. IBRANCE may impair fertility in males and has the potential to cause genotoxicity. Advise male patients with female partners of reproductive potential to use effective contraception during IBRANCE treatment and for 3 months after the last dose. Advise females to inform their healthcare provider of a known or suspected pregnancy. Advise women not to breastfeed during IBRANCE treatment and for 3 weeks after the last dose because of the potential for serious adverse reactions in nursing infants.

The most common adverse reactions (≥10%) of any grade reported in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were neutropenia (80% vs 6%), infections (60% vs 42%), leukopenia (39% vs 2%), fatigue (37% vs 28%), nausea (35% vs 26%), alopecia (33% vs 16%), stomatitis (30% vs 14%), diarrhea (26% vs 19%), anemia (24% vs 9%), rash (18% vs 12%), asthenia (17% vs 12%), thrombocytopenia (16% vs 1%), vomiting (16% vs 17%), decreased appetite (15% vs 9%), dry skin (12% vs 6%), pyrexia (12% vs 9%), and dysgeusia (10% vs 5%).

The most frequently reported Grade ≥3 adverse reactions (≥5%) in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were neutropenia (66% vs 2%), leukopenia (25% vs 0%), infections (7% vs 3%), and anemia (5% vs 2%).

Lab abnormalities of any grade occurring in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were decreased WBC (97% vs 25%), decreased neutrophils (95% vs 20%), anemia (78% vs 42%), decreased platelets (63% vs 14%), increased aspartate aminotransferase (52% vs 34%), and increased alanine aminotransferase (43% vs 30%).

The most common adverse reactions (≥10%) of any grade reported in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were neutropenia (83% vs 4%), leukopenia (53% vs 5%), infections (47% vs 31%), fatigue (41% vs 29%), nausea (34% vs 28%), anemia (30% vs 13%), stomatitis (28% vs 13%), diarrhea (24% vs 19%), thrombocytopenia (23% vs 0%), vomiting (19% vs 15%), alopecia (18% vs 6%), rash (17% vs 6%), decreased appetite (16% vs 8%), and pyrexia (13% vs 5%).

The most frequently reported Grade ≥3 adverse reactions (≥5%) in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were neutropenia (66% vs 1%) and leukopenia (31% vs 2%).

Lab abnormalities of any grade occurring in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were decreased WBC (99% vs 26%), decreased neutrophils (96% vs 14%), anemia (78% vs 40%), decreased platelets (62% vs 10%), increased aspartate aminotransferase (43% vs 48%), and increased alanine aminotransferase (36% vs 34%).

Avoid concurrent use of strong CYP3A inhibitors. If patients must be administered a strong CYP3A inhibitor, reduce the IBRANCE dose to 75 mg. If the strong inhibitor is discontinued, increase the IBRANCE dose (after 3-5 half-lives of the inhibitor) to the dose used prior to the initiation of the strong CYP3A inhibitor. Grapefruit or grapefruit juice may increase plasma concentrations of IBRANCE and should be avoided. Avoid concomitant use of strong CYP3A inducers. The dose of sensitive CYP3A substrates with a narrow therapeutic index may need to be reduced as IBRANCE may increase their exposure.

For patients with severe hepatic impairment (Child-Pugh class C), the recommended dose of IBRANCE is 75 mg. The pharmacokinetics of IBRANCE have not been studied in patients requiring hemodialysis.