Cardiac safety of dual anti-HER2 blockade with pertuzumab plus trastuzumab (P+T) in the APHINITY trial

510

Background: Trastuzumab (T) increases the incidence of cardiac events (CEs) in patients (pts) with early breast cancer (BC). Dual blockade with P+T improves BC outcomes and is the standard of care for high-risk HER2-positive BC pts following the phase 3 APHINITY trial that evaluated the addition of P or placebo (Pla) to T and chemotherapy (CT). We analyzed the cardiac safety of P+T in APHINITY. Methods: APHINITY eligibility required a left ventricular ejection fraction (LVEF) ≥55% at study entry. LVEF assessment was performed every 3 months (mos) during treatment, every 6 mos up to month 36, and yearly thereafter. Primary CE was defined as heart failure (HF) class III/IV and a significant decrease in LVEF of at least 10 percentage points from baseline and to <50%, or cardiac death. Secondary CE was defined as a confirmed significant decrease in LVEF or CEs confirmed by the cardiac advisory board. Results: The safety analysis population consists of 4,769 pts. With 74 mos median follow-up (FU), CEs were observed in 159 pts (3.3%): 83 (3.5%) in the P+T and 76 (3.2%) in Pla+T arms, respectively. Most CEs occurred during anti-HER2 therapy: 123/159 (77.4%) and were asymptomatic or mildly symptomatic LVEF decrease (133/159; 83.6%) (Table 1). There were 2 cardiac deaths in each arm (0.1%). More CEs occurred in pts receiving an anthracycline-based CT compared to those receiving non-anthracycline CT (139 vs. 20 CEs, respectively). Acute recovery from a CE based on subsequent LVEF values was observed in 127/155 pts (81.9%). Conclusions: Dual blockade with P+T does not increase the risk of CE compared to Pla+T alone. The use of anthracycline-based CT increases the risk of a CE; hence non-anthracycline CT may be considered particularly in pts with other cardiovascular risk factors. Clinical trial information: NCT01358877. [Table: see text]

APHINITY trial (BIG 4-11): A randomized comparison of chemotherapy (C) plus trastuzumab (T) plus placebo (Pla) versus chemotherapy plus trastuzumab (T) plus pertuzumab (P) as adjuvant therapy in patients (pts) with HER2-positive early breast cancer (EBC)

LBA500

Background: In previous trials P significantly prolonged progression free and overall survival and increased pCR rates when added to T+C in pts with HER2-positive breast cancer (BC). The APHINITY trial was designed to test whether the addition of P to adjuvant T+C improves pt outcomes. Methods: Pts with adequately excised HER2-positive, pT1-3 EBC were randomly assigned to receive standard adjuvant C plus one year of either T + P or T + Pla. Eligible pts had either node-positive disease, or node-negative disease (pN0) and a tumor size of > 1.0 cm. Pts with pN0, T1b tumors with high risk features were initially eligible. The primary efficacy endpoint was invasive disease-free survival (IDFS); we assumed a 3-year IDFS of 91.8% with P and 89,.2% with Pla. Results: 4805 pts were randomized to C and T plus either P (n = 2400) or Pla (n = 2405). Baseline demographics and tumor characteristics between the arms were well balanced, with 63% and 36% of pts having node-positive and hormone receptor negative EBC respectively. P and Pla treatments were completed in 84.5% and 87.4% of patients, respectively. IDFS events occurred in 171 (7.1%) P pts and 210 (8.7%) Pla pts (hazard ratio (HR) 0.81 (95% CI 0.68-1.00), P = 0.045). Estimates of IDFS at 3 years were 94.1% and 93.2% in the P and Pla arms, respectively. The node-positive cohort had a 3-year IDFS rate of 92.0% for P compared with 90.2% for Pla (HR 0.77 (95% CI 0.62-0.96), P = 0.019). The pN0 cohort had a 3-year IDFS rate of 97.5% for P and 98.4% for Pla; HR = 1.13 (95% CI 0.68-1.86). The safety profile of P was consistent with previous trials. For the primary cardiac endpoint (heart failure or cardiac death) and secondary cardiac endpoint (asymptomatic or mildly symptomatic LVEF decline) rates were low, 0.7% vs 0.3% and 2.7% vs 2.8%, in the P and Pla arms, respectively. Diarrhea grade ≥3 was more frequent with P (9.9% vs 3.7%). Conclusions: The APHINITY trial met its primary endpoint: P significantly improved IDFS in patients with HER2-positive EBC when added to T+C. No new safety signals were identified. Clinical trial information: NCT01358877.

APHINITY trial (BIG 4-11): A randomized comparison of chemotherapy (C) plus trastuzumab (T) plus placebo (Pla) versus chemotherapy plus trastuzumab (T) plus pertuzumab (P) as adjuvant therapy in patients (pts) with HER2-positive early breast cancer (EBC)

LBA500

The full, final text of this abstract will be available at abstracts.asco.org at 7:30 AM (EDT) on Monday, June 5, 2017, and in the Annual Meeting Proceedings online supplement to the June 20, 2017, issue of the Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

Long-term (8 years) assessment of trastuzumab-related cardiac events in the HERA trial

525

Background: Trastuzumab-related cardiac dysfunction may occur in patients (pts) treated with adjuvant therapy and it is mostly reversible. We report the long-term outcome of pts with cardiac dysfunction treated with adjuvant trastuzumab (T) in the Herceptin Adjuvant (HERA) trial. Methods: HERA is a three-arm, randomized trial that compared 1 year or 2 years of T with observation (Obs) in women with HER2-positive early breast cancer (EBC). Eligible pts had a left ventricular ejection fraction (LVEF) ≥ 55% at study entry (i.e. after completion of (neo)adjuvant chemotherapy with or without radiotherapy). Cardiac function was closely monitored throughout the trial. This analysis at 8-year median follow-up considers pts randomly assigned to 1 year or 2 years of T therapy or observation. Results: 5102 pts were randomized to HERA. The “as treated” safety population is considered: 2 years T (N=1,673), 1 year T (N=1,682) and Obs (N=1,744). Cardiac events leading to T discontinuation in the 1-year and 2-year arms were observed in 5.2% and 9.4% of pts, respectively. Cardiac death, severe congestive heart failure (CHF) and confirmed significant LVEF drop remained low in all three arms (Table). In the 1 year T arm, 71.4% of pts with severe CHF, and 81.2% of pts with confirmed LVEF drop recovered cardiac function (at least 2 sequential LVEF assessments > 50%). The median time to recovery was 9.7 months and 6.3 months, respectively. In the 2 years T arm, 87.5% of pts with confirmed LVEF drop recovered cardiac function and median time to recovery was 8.3 months. Conclusions: At 8-year median follow-up the incidence of cardiac events during adjuvant T remains low and these events are mostly reversible. These results confirm low cardiac events when T is given as part of the adjuvant therapy for pts with HER2-positive EBC. Clinical trial information: NCT00045032. [Table: see text]

Glucokinase activator PSN-GK1 displays enhanced antihyperglycaemic and insulinotropic actions

AIMS/HYPOTHESIS

We evaluated the insulinotropic and antihyperglycaemic actions of glucokinase activators (GKAs), especially through acute and subchronic studies in rodent diabetes models with (2R)-2-(4-cyclopropanesulphonylphenyl)-N-(5-fluorothiazol-2-yl)-3-(tetrahydropyran-4-yl)propionamide (PSN-GK1), a novel and potent GKA.

MATERIALS AND METHODS

The action of PSN-GK1 on or in the following were investigated: (1) on human liver glucokinase, insulin secretion from MIN6 cells and 2-deoxy-D: -[(3)H]glucose (2-DG) uptake into rat hepatocytes; and (2) in Zucker diabetic fatty rats and in non-diabetic C57Bl/6, diabetic db/db and ob/ob mice.

RESULTS

At 5 mmol/l glucose, PSN-GK1 activated glucokinase (4.3-fold, median effective concentration [EC(50)] 130 nmol/l), increased MIN6 insulin secretion (26-fold, EC(50) 267 nmol/l) and 2-DG hepatocytic uptake (threefold, EC(50) 1 micromol/l); at higher glucose concentrations, EC(50)s and fold-effectiveness were both lower. In C57Bl/6 mice, PSN-GK1 reduced blood glucose at 1 and 10 mg/kg (by mouth), but insulin was increased significantly at only the higher dose. In hyperinsulinaemic 10-mmol/l glucose clamps, PSN-GK1 increased 2-DG incorporation into liver glycogen sixfold, directly demonstrating liver effects. PSN-GK1 improved glycaemic profiles in db/db mice and Zucker diabetic fatty rats, diabetic animal models in which GKA efficacy has not previously been described, without causing hypoglycaemia. In ob/ob mice, it dose-dependently reduced excursions in OGTTs. Moreover, after subchronic administration, no tachyphylaxis was evident and glycaemia was improved without alterations to lipid levels, liver weight, glycogen content or body weight.

CONCLUSIONS/INTERPRETATION

PSN-GK1 was potently antihyperglycaemic through its effects on insulin release and hepatic glucose metabolism. It is one of the most potent GKAs described in the literature and is active in diabetic animal models where GKAs have not been reported to show efficacy to date. Ongoing human trials are investigating the potential of this novel therapeutic approach.

Actions of kainate and AMPA selective glutamate receptor ligands on nociceptive processing in the spinal cord

Kainate receptors expressing the GluR5 subunit of glutamate receptor are present at high levels on small diameter primary afferent neurones that are considered to mediate nociceptive inputs. This suggests that GluR5 selective ligands could be novel analgesic agents. The role of kainate receptors on C fibre primary afferents has therefore been probed using three compounds that are selective for homomeric GluR5 receptors. The agonist, ATPA, and the antagonists, LY294486 and LY382884, have been tested in four models of nociception: responses evoked by noxious stimulation of the periphery have been recorded electrophysiologically (1) from hemisected spinal cords from neonatal rats in vitro, (2) from single motor units in adult rats in vivo, (3) from dorsal horn neurones in adult rats in vivo, and (4) in hotplate tests with conscious mice. In some protocols comparisons were made with the AMPA selective antagonist GYKI 53655. The agonist ATPA reduced nociceptive reflexes in vitro, but failed to have effects in vivo. In all tests, the GluR5 antagonists reduced nociceptive responses but only at doses that also affected responses to exogenous AMPA. The AMPA antagonist reduced nociceptive responses at doses causing relatively greater reductions of responses to exogenous AMPA. The results indicate that GluR5 selective ligands do reduce spinal nociceptive responses, but they are not strongly analgesic under these conditions of acute nociception.