The effects of adding palbociclib to endocrine therapy to treat advanced breast cancer: a plain language summary of a study using the PALOMA-2 and PALOMA-3 trial results.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of an article that reported results of a study using data from two phase 3 clinical trials called "PALOMA-2" and "PALOMA-3." Both PALOMA-2 and PALOMA-3 trials included women with HR+/HER2- advanced breast cancer. HR+/HER2- breast cancer means the breast cancer cells of these women have receptors for female sex hormones and little or no HER2 receptors. Both PALOMA trials tested the effect of adding a medication called palbociclib (brand name, Ibrance®) to a hormone therapy. Hormone therapy, also known as endocrine therapy, is a treatment that blocks or removes hormones that cause cancer cells to grow and divide. In both trials, women took endocrine therapy with either palbociclib or a placebo. WHAT WAS THE AIM OF THIS STUDY?: The researchers aimed to see if the results from the PALOMA trials were similar for subgroups of women in the 2 trials. The subgroups in the study included women who shared certain features about their cancer or treatment history, for example, women whose cancer had spread to the liver. For each subgroup, the study compared the results from the 2 treatment groups: (1) women who took palbociclib plus endocrine therapy, and (2) women who took placebo plus endocrine therapy. WHAT WERE THE RESULTS & WHAT DO THEY MEAN?: The same effect was found in all subgroups. Compared with those who took placebo, women who took palbociclib lived longer without their cancer getting worse (growing or spreading). Also, among women who had chemotherapy after stopping the trial treatment, those who took palbociclib started chemotherapy later than those who took placebo. Because palbociclib slows cancer growth and leads to tumor shrinkage, this may have played a part in starting chemotherapy later. These results show that palbociclib plus endocrine therapy is better at slowing the progression of advanced HR+/HER2- breast cancer than endocrine therapy alone. This can be said for women with different advanced HR+/HER2- breast cancer features and treatment history. Overall, the results support women taking palbociclib with an endocrine therapy if they have advanced HR+/HER2- breast cancer.

Effect of palbociclib plus endocrine therapy on time to chemotherapy across subgroups of patients with hormone receptor‒positive/human epidermal growth factor receptor 2‒negative advanced breast cancer: Post hoc analyses from PALOMA-2 and PALOMA-3.

BACKGROUND: Previous analyses from the PALOMA-2 and PALOMA-3 studies showed that palbociclib (PAL) plus endocrine therapy (ET) prolongs time to first subsequent chemotherapy (TTC) versus placebo (PBO) plus ET in the overall population of patients with hormone receptor‒positive/human epidermal growth factor receptor 2‒negative (HR+/HER2-) advanced breast cancer (ABC). Here, we evaluated TTC in relevant patient subgroups. METHODS: These post hoc analyses evaluated TTC by subgroup using data from 2 randomized, phase 3 studies of women with HR+/HER2- ABC. In PALOMA-2, postmenopausal patients previously untreated for ABC were randomized 2:1 to receive PAL (125 mg/day, 3/1-week schedule) plus letrozole (LET; 2.5 mg/day; n = 444) or PBO plus LET (n = 222). In PALOMA-3, premenopausal or postmenopausal patients whose disease had progressed after prior ET were randomized 2:1 to receive PAL (125 mg/day, 3/1-week schedule) plus fulvestrant (FUL; 500 mg; n = 347) or PBO plus FUL (n = 174). RESULTS: First subsequent chemotherapy was received by 35.5% and 56.2% in PALOMA-2 and PALOMA-3 after progression on palbociclib plus ET or placebo plus ET. Across all subgroups analyzed, the median progression-free survival (PFS) was longer in the PAL plus ET arm than the PBO plus ET arm. TTC was longer with PAL plus ET versus PBO plus ET across the same patient subgroups in both studies. CONCLUSIONS: Across all subgroups, PAL plus ET versus PBO plus ET had longer median PFS and resulted in prolonged TTC in both the PALOMA-2 and PALOMA-3 studies. Pfizer Inc (NCT01740427, NCT01942135).

Phase I/II clinical trial of temsirolimus and lenalidomide in patients with relapsed and refractory lymphomas.

The PI3K/Akt/mTOR (PAM) axis is constitutively activated in multiple lymphoma subtypes and is a promising therapeutic target. The mTOR inhibitor temsirolimus (TEM) and the immunomodulatory agent lenalidomide (LEN) have overlapping effects within the PAM axis with synergistic potential. This multicenter phase I/II study evaluated combination therapy with TEM/LEN in patients with relapsed and refractory lymphomas. Primary endpoints of the phase II study were rates of complete (CR) and overall response (ORR). There were 18 patients in the phase I dose-finding study, and TEM 25 mg weekly and LEN 20 mg on day 1 through day 21 every 28 days was established as the recommended phase II dose. An additional 93 patients were enrolled in the phase II component with three cohorts: diffuse large B-cell lymphoma (DLBCL, n=39), follicular lymphoma (FL, n=15), and an exploratory cohort of other lymphoma histologies with classical Hodgkin lymphoma (cHL) comprising the majority (n=39 total, n=20 with cHL). Patients were heavily pretreated with a median of four (range, 1-14) prior therapies and one-third with relapse following autologous stem cell transplantation (ASCT); patients with cHL had a median of six prior therapies. The FL cohort was closed prematurely due to slow accrual. ORR were 26% (13% CR) and 64% (18% CR) for the DLBCL and exploratory cohorts, respectively. ORR for cHL patients in the exploratory cohort, most of whom had relapsed after both brentuximab vedotin and ASCT, was 80% (35% CR). Eight cHL patients (40%) proceeded to allogeneic transplantation after TEM/LEN therapy. Grade ≥3 hematologic adverse events (AE) were common. Three grade 5 AE occurred. Combination therapy with TEM/LEN was feasible and demonstrated encouraging activity in heavily-pretreated lymphomas, particularly in relapsed/refractory cHL (clinicaltrials gov. Identifier: NCT01076543).

A randomized phase 2 study of temsirolimus and cetuximab versus temsirolimus alone in recurrent/metastatic, cetuximab-resistant head and neck cancer: The MAESTRO study.

BACKGROUND: Patients with cetuximab-resistant, recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) have poor outcomes. This study hypothesized that dual blockade of mammalian target of rapamycin and epidermal growth factor receptor (EGFR) would overcome cetuximab resistance on the basis of the role of phosphoinositide 3-kinase signaling in preclinical models of EGFR resistance. METHODS: In this multicenter, randomized clinical study, patients with recurrent/metastatic HNSCC with documented progression on cetuximab (in any line in the recurrent/metastatic setting) received 25 mg of temsirolimus weekly plus cetuximab at 400/250 mg/m2 weekly (TC) or single-agent temsirolimus (T). The primary outcome was progression-free survival (PFS) in the TC arm versus the T arm. Response rates, overall survival, and toxicity were secondary outcomes. RESULTS: Eighty patients were randomized to therapy with TC or T alone. There was no difference for the primary outcome of median PFS (TC arm, 3.5 months; T arm, 3.5 months). The response rate was 12.5% in the TC arm (5 responses, including 1 complete response [2.5%]) and 2.5% in the T arm (1 partial response; P = .10). Responses were clinically meaningful in the TC arm (range, 3.6-9.1 months) but not in the T-alone arm (1.9 months). Fatigue, electrolyte abnormalities, and leukopenia were the most common grade 3 or higher adverse events and occurred in less than 20% of patients in both arms. CONCLUSIONS: The study did not meet its primary endpoint of improvement in PFS. However, TC induced responses in cetuximab-refractory patients with good tolerability. The post hoc observation of activity in patients with acquired resistance (after prior benefit from cetuximab monotherapy) may warrant further investigation.

Efficacy and safety of palbociclib plus endocrine therapy in North American women with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer.

Palbociclib is a cyclin-dependent kinase 4/6 inhibitor indicated for treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer in combination with endocrine therapy. We investigated the efficacy and safety of palbociclib in patients enrolled in North America during two-phase 3 trials: PALOMA-2 (n = 267, data cutoff: May 31, 2017) and PALOMA-3 (n = 240, data cutoffs: April 13, 2018, for overall survival, October 23, 2015, for all other outcomes). In PALOMA-2, treatment-naïve postmenopausal patients with advanced breast cancer were randomized 2:1 to palbociclib (125 mg/d; 3 weeks on/1 week off [3/1]) plus letrozole (2.5 mg/d, continuous) or placebo plus letrozole. In PALOMA-3, patients who progressed on prior endocrine therapy were randomized 2:1 to palbociclib (125 mg/d; 3/1) plus fulvestrant (500 mg, per standard of care) or placebo plus fulvestrant; pre/perimenopausal patients received ovarian suppression with goserelin. Palbociclib plus endocrine therapy prolonged median progression-free survival vs placebo plus endocrine therapy in North American patients (PALOMA-2: 25.4 vs 13.7 months, hazard ratio, 0.54 [95% CI, 0.40-0.74], P < .0001; PALOMA-3: 9.9 vs 3.5 months, hazard ratio, 0.52 [95% CI, 0.38-0.72], P < .0001). Objective response and clinical benefit response rates were greater with palbociclib vs placebo in North American patients in both trials. While overall survival data are not yet mature for PALOMA-2, median overall survival was increased in PALOMA-3 (32.0 vs 24.7 months, hazard ratio, 0.75 [95% CI, 0.53-1.04]), though this did not reach statistical significance (P = .0869). Safety profiles in North American patients were similar to those of the overall populations; neutropenia was the most common treatment-emergent adverse event. No new safety signals were observed. In summary, palbociclib plus endocrine therapy is an effective treatment option for North American women with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer.

Randomized Phase Ib/II Study of Gemcitabine Plus Placebo or Vismodegib, a Hedgehog Pathway Inhibitor, in Patients With Metastatic Pancreatic Cancer.

PURPOSE: Sonic hedgehog (SHH), an activating ligand of smoothened (SMO), is overexpressed in > 70% of pancreatic cancers (PCs). We investigated the impact of vismodegib, an SHH antagonist, plus gemcitabine (GV) or gemcitabine plus placebo (GP) in a multicenter phase Ib/randomized phase II trial and preclinical PC models. PATIENTS AND METHODS: Patients with PC not amenable to curative therapy who had received no prior therapy for metastatic disease and had Karnofsky performance score ≥ 80 were enrolled. Patients were randomly assigned in a one-to-one ratio to GV or GP. The primary end point was progression-free-survival (PFS). Exploratory correlative studies included serial SHH serum levels and contrast perfusion computed tomography imaging. To further investigate putative biologic mechanisms of SMO inhibition, two autochthonous pancreatic cancer models (Kras(G12D); p16/p19(fl/fl); Pdx1-Cre and Kras(G12D); p53(R270H/wt); Pdx1-Cre) were studied. RESULTS: No safety issues were identified in the phase Ib portion (n = 7), and the phase II study enrolled 106 evaluable patients (n = 53 in each arm). Median PFS was 4.0 and 2.5 months for GV and GP arms, respectively (95% CI, 2.5 to 5.3 and 1.9 to 3.8, respectively; adjusted hazard ratio, 0.81; 95% CI, 0.54 to 1.21; P = .30). Median overall survival (OS) was 6.9 and 6.1 months for GV and GP arms, respectively (95% CI, 5.8 to 8.0 and 5.0 to 8.0, respectively; adjusted hazard ratio, 1.04; 95% CI, 0.69 to 1.58; P = .84). Response rates were not significantly different. There were no significant associations between correlative markers and overall response rate, PFS, or OS. Preclinical trials revealed no significant differences with vismodegib in drug delivery, tumor growth rate, or OS in either model. CONCLUSION: The addition of vismodegib to gemcitabine in an unselected cohort did not improve overall response rate, PFS, or OS in patients with metastatic PC. Our preclinical and clinical results revealed no statistically significant differences with respect to drug delivery or treatment efficacy using vismodegib.

Dasatinib in previously treated metastatic colorectal cancer: a phase II trial of the University of Chicago Phase II Consortium.

BACKGROUND: Treatment options for metastatic colorectal cancer (CRC) are limited after a fluoropyrimidine, oxaliplatin and irinotecan; novel agents need to be explored in this setting. Dasatinib, an oral inhibitor of Src family kinases, inhibits proliferation in CRC cell lines and has antitumor activity in CRC xenograft models. PATIENTS AND METHODS: We conducted a multi-center phase II trial of dasatinib in unresectable, previously-treated metastatic CRC patients. No more than 2 prior chemotherapy regimens were permitted, which must have contained a fluoropyrimidine, oxaliplatin and irinotecan. The primary endpoint was progression-free survival (PFS) at 4 months. The Simon two-stage design required that at least 5 of the first 19 patients be progression-free at 4 months to expand to a second stage. RESULTS: Nineteen patients enrolled at 9 centers. The study was terminated after the first stage due to lack of efficacy. There were no objective responses; 1 patient (5%) had stable disease for 7.3 months. The PFS rate at 4 months was 5.3% (90% CI: 0.3, 22.6). Median PFS was 1.6 months (90% CI: 1.4, 1.8). Median overall survival was 5.1 months (90% CI: 2.4, 6.3). Grade 3/4 toxicities included fatigue in 16% of patients, and anemia, anorexia, nausea/vomiting and dyspnea in 11%. CONCLUSION: Dasatinib is inactive as a single agent in previously treated metastatic CRC patients.

Vandetanib versus gefitinib in patients with advanced non-small-cell lung cancer: results from a two-part, double-blind, randomized phase ii study.

PURPOSE: Vandetanib is a once-daily oral inhibitor of vascular endothelial growth factor receptor (VEGFR) and epidermal growth factor receptor (EGFR) signaling. In this two-part phase II study, the efficacy and safety of vandetanib was compared with that of gefitinib, an inhibitor of EGFR signaling. PATIENTS AND METHODS: Patients (N = 168) with locally advanced or metastatic (stage IIIB/IV) non-small-cell lung cancer (NSCLC), after failure of first-line with or without second-line platinum-based chemotherapy, received once-daily vandetanib 300 mg (n = 83) or gefitinib 250 mg (n = 85) until disease progression or evidence of toxicity (part A). After a 4-week washout period, eligible patients had the option to switch to the alternative treatment (part B). Progression-free survival (PFS) was the primary efficacy assessment in part A, which was designed to have a higher than 75% power to detect a 33% prolongation of PFS at a one-sided significance level of .2. RESULTS: In part A, vandetanib prolonged PFS compared with gefitinib (hazard ratio = 0.69; 95% CI, 0.50 to 0.96; one-sided P = .013). Patients receiving vandetanib experienced adverse events that were manageable and generally consistent with inhibition of EGFR and VEGFR signaling, including diarrhea, rash, and hypertension. There were no unexpected safety findings with gefitinib. Overall survival, a secondary assessment, was not significantly different between patients initially randomly assigned to either vandetanib or gefitinib. CONCLUSION: The primary efficacy objective was achieved, with vandetanib demonstrating a significant prolongation of PFS versus gefitinib. Vandetanib 300 mg/d is currently being evaluated as a monotherapy in two randomized phase III studies in advanced NSCLC.