introduction
The pathophysiology of chemotherapy-induced nausea and vomiting (CINV) is multifactorial
involving several neurotransmitters and receptors [1]. Combination antiemetic regimens
targeting multiple molecular pathways associated with emesis have become the standard
of care for prevention of CINV. This is supported by compelling clinical research
and antiemetic guidelines [2, 3] which recommend a prophylactic combination of a 5-HT3
receptor antagonist (RA) [palonosetron (PALO) as ‘preferred’] and dexamethasone (DEX)
when administering moderately emetogenic chemotherapy (MEC) and a 5-HT3 RA, DEX and
a neurokinin-1 (NK1) RA when administering highly emetogenic chemotherapy (HEC).
Anthracycline–cyclophosphamide (AC) chemotherapy is still considered to be moderately
emetogenic according to regulatory authorities and evidence-based emetogenicity classification
schemes [3]. Patients receiving AC tend to have additional patient-related risk factors
(e.g. young age, female gender) which put them at greater risk for CINV; studies have
shown that the addition of a NK1 RA to the 5-HT3 RA and DEX regimen is beneficial
in this setting [4]. Therefore, guidelines recommend that this group of patients also
receive a triple-combination antiemetic therapy on day 1.
While data support the reputed notion that guideline conformity will improve CINV
control for patients, unfortunately, adherence to antiemetic guidelines is suboptimal
[5]. Consequently, even with effective agents available, many patients still suffer
from CINV, particularly nausea during the delayed (25–120 h) phase following chemotherapy
[2].
NEPA is an oral fixed-dose combination of netupitant (NETU), a new highly selective
NK1 RA and PALO, a pharmacologically distinct [6] and clinically superior [2] 5-HT3
RA. The unique pharmacological characteristics of PALO result in long-lasting inhibition
of the 5-HT3 receptor function. PALO has also been shown to inhibit the cross-talk
between the 5-HT3 and NK1 receptors and, recently, the combination of PALO with NETU
has been shown to work synergistically in enhancing inhibition of the substance P
response compared with either antagonist alone [7]. These findings offer a possible
explanation behind its unique efficacy during the delayed phase and also suggest the
potential to enhance prevention of delayed CINV when used in combination with NETU.
In a phase II dose-ranging study [8] in patients receiving HEC, the NEPA combination
of NETU 300 mg + PALO 0.50 mg was the most effective dose studied, with an incremental
clinical benefit over lower NEPA doses for all efficacy end points. This was the basis
for the selection of the fixed-dose combination in the current trial. This phase III
study was designed to demonstrate the superiority of NEPA over PALO in preventing
CINV in patients receiving AC-based MEC and to evaluate NEPA's safety.
patients and methods
study design
This was a phase III, multicenter, randomized, double-blind, double-dummy, parallel
group study conducted at 177 enrolling sites in 15 countries (Argentina, Belarus,
Brazil, Bulgaria, Croatia, Germany, Hungary, India, Italy, Mexico, Poland, Romania,
Russia, Ukraine and the United States) between April 2011 and November 2012. The protocol
was approved by ethical review committees, all patients provided written informed
consent, and all study sites followed GCP, ICH, Declaration of Helsinki principles,
local laws and regulations.
patients
Eligible patients were ≥18 years, naïve to chemotherapy, and scheduled to receive
their first course of an AC MEC regimen for treatment of a solid malignant tumor.
Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance
status of 0, 1 or 2. Patients were not eligible if they were scheduled to receive:
(i) HEC from day 1–5 or additional MEC from day 2–5 following chemotherapy, (ii) radiation
therapy to the abdomen or pelvis within 1 week before day 1 or between day 1 and 5,
or 3) a bone marrow or stem-cell transplant. Patients were not allowed to receive
any drug with known or potential antiemetic efficacy within 24 h before day 1 and
were excluded if they experienced any vomiting, retching or mild nausea within 24
h before day 1. Patients were not to have had any serious cardiovascular disease history
or predisposition to cardiac conduction abnormalities, with the exception of incomplete
right bundle branch block. Because NETU is a moderate inhibitor of CYP3A4, use of
any CYP3A4 inducer within 4 weeks, use of a strong or moderate inhibitor within 1
week or scheduled to receive CYP3A4 inhibitors, inducers or certain substrates as
concomitant medication was prohibited (supplementary Table S1, available at Annals
of Oncology online).
treatment
Patients were randomly assigned to receive either NEPA (NETU 300 mg/PALO 0.50 mg)
plus 12 mg DEX or PALO 0.50 mg plus 20 mg DEX on day 1 of chemotherapy. Due to the
increased exposure to DEX when given in combination with NETU [9], the DEX dose in
the NEPA group was reduced to achieve DEX exposure similar to that in the PALO group.
The 0.50 mg oral PALO dose was selected based on a noninferiority efficacy trial evaluating
three oral PALO doses, 0.25, 0.50 and 0.75 mg, compared with i.v. PALO 0.25 mg [10].
NEPA and PALO were administered 60 min and DEX 30 min before chemotherapy on day 1.
Patients were stratified by region [United States, Latin America/Mexico, Europe, Commonwealth
of Independent States (i.e. former Soviet Republics) and Asia] and age class (<55
and ≥55 years). Blinding was maintained in all groups with the use of matching identical
placebos. The chemotherapy consisted of either cyclophosphamide i.v. (500–1500 mg/m2)
and doxorubicin i.v. (≥40 mg/m2) or cyclophosphamide i.v. (500–1500 mg/m2) and epirubicin
i.v. (≥60 mg/m2).
The use of rescue medication for treatment of nausea/vomiting was considered treatment
failure. Metoclopramide tablets were provided; however, the investigator was authorized
to use an alternative rescue (excluding 5-HT3 or NK1 RAs as well as PALO) at his/her
discretion.
After completion of cycle 1, patients had the option to participate in a multiple-cycle
extension, receiving the same treatment as assigned in cycle 1. There was no prespecified
limit of the number of repeat consecutive cycles. Findings from this multiple-cycle
extension will be the subject of a separate publication.
assessments
From the start of chemotherapy infusion on day 1 through the morning of day 6 (0–120
h), each patient completed a diary, capturing information pertaining to the timing
and duration of each emetic episode, severity of nausea and rescue medications taken.
An emetic episode was defined as one or more continuous vomits or retches. Severity
of nausea was evaluated on a daily basis (for the preceding 24 h) using a 100-mm horizontal
visual analog scale (VAS). The left end of the scale (0 mm) was labeled as ‘no nausea,’
and the right end of the scale (100 mm) was labeled as ‘nausea as bad as it could
be’.
The Functional Living Index-Emesis (FLIE) questionnaire [consisting of nine nausea-specific
(nausea domain) and nine vomiting-specific (vomiting domain) items] was used to assess
the impact of CINV on patients' daily lives. Patients completed this questionnaire
on day 6, assessing the impact of CINV on their daily functioning during the 120 h
after chemotherapy administration. The proportion of patients with scores reflecting
‘no impact on daily life’ (NIDL) (i.e. nausea/vomiting domain score >54, total FLIE
score >108) was evaluated.
The primary efficacy end point was complete response (CR: no emesis, no rescue medication)
during the delayed phase after the start of chemotherapy of cycle 1. Key secondary
efficacy end points included CR during the acute (0–24 h) and overall (0–120 h) phases;
other secondary efficacy end points were complete protection (CR + no significant
nausea), no emesis and no significant nausea (VAS score of <25 mm) during the acute,
delayed and overall phases while other efficacy end points included FLIE scores during
the overall phase. Safety was assessed by adverse events, clinical laboratory evaluations,
physical examinations, vital signs and electrocardiograms (ECGs).
statistical analysis
The primary aim of this study was to demonstrate the superiority of NEPA over PALO
based on the proportion of patients with a CR during the delayed phase of cycle 1.
The primary efficacy analysis was carried out using a two-sided Cochran–Maentel–Haenszel
(CMH) test including treatment, age class and region as strata. NEPA was to be declared
superior to PALO if the two-sided P-value was ≤0.05 and in favor of NEPA. A hierarchical
procedure was applied to control type I error inflation (i.e. CR during the delayed,
acute and overall phases were tested sequentially only if the previous test succeeded).
No emesis, complete protection, no signification nausea and FLIE were also analyzed
utilizing the CMH test.
The sample size was estimated to be 1460 patients (730 per group). The assumption
was a responder rate of 60% during the delayed phase for NEPA and 51% for PALO. For
a two-sided test of difference, using α = 0.050, a sample size of 661 assessable patients
per group was needed to ensure 90% power to detect the 9% difference. This number
was increased to 730 per group to ensure an adequate number of assessable patients.
The number of patients who experienced treatment-emergent adverse events or ECG abnormalities
was listed and summarized by treatment group.
The full analysis set population (efficacy analyses) was defined as all patients who
were randomized and received protocol-required MEC and study treatment. The safety
analysis population consisted of all patients who received study treatment and had
at least one safety assessment after the treatment administration.
results
A total of 1455 patients were randomized into the study. Five patients did not receive
the protocol-required MEC and study drug and one additional patient received study
drug but not MEC; therefore, 1450 and 1449 patients represented the safety and full
analysis set populations, respectively (Figure 1).
Figure 1.
Consort diagram of the disposition of patients.
Baseline characteristics were similar between treatment groups (Table 1).
Table 1.
Patient baseline and disease characteristics
Characteristic
NEPA (N = 724)
PALO (N = 725)
Gender
Female
98.2%
97.9%
Male
1.8%
2.1%
Age (years)
Median
54.0
54.0
<55
51.2%
51.3%
≥55
48.8%
48.7%
Ethnic group
White
79.1%
80.0%
Asian
14.0%
14.2%
Hispanic
6.4%
5.0%
Black
0.1%
0.3%
Other
0.4%
0.6%
Cancer type
Breast
97.7%
97.2%
Other
2.3%
2.8%
ECOG Performance Status
0
69.6%
69.1%
1
29.6%
30.8%
2
0.8%
0.1%
Chemotherapy
Cyclophosphamide
99.9%
100%
Doxorubicin
68.0%
63.7%
Epirubicin
32.0%
36.3%
efficacy
For the primary efficacy comparison, NEPA was superior to PALO during the delayed
phase with a CR rate of 76.9% versus 69.5% (P = 0.001) (Figure 2). CR rates were also
significantly higher for NEPA compared with PALO during the acute and overall phases.
Figure 2.
Complete response (no emesis, no rescue medication).
Similarly, NEPA was consistently more effective than PALO during the delayed and overall
phases for secondary efficacy end points of no emesis, no significant nausea and complete
protection as well as during the acute phase for no emesis (Table 2). For the FLIE
assessment, a greater proportion of NEPA-treated patients reported NIDL for the nausea,
vomiting and combined domains compared with PALO (Figure 3).
Table 2.
Secondary efficacy end points
NEPA (N = 724)
PALO (N = 725)
P-value
No emesis
Acute
90.9%
87.3%
0.025
Delayed
81.8%
75.6%
0.004
Overall
79.8%
72.1%
<0.001
No significant nausea
Acute
87.3%
87.9%
0.747
Delayed
76.9%
71.3%
0.014
Overall
74.6%
69.1%
0.020
Complete protection
Acute
82.3%
81.1%
0.528
Delayed
67.3%
60.3%
0.005
Overall
63.8%
57.9%
0.020
Figure 3.
Proportion of patients with no impact on daily living (NIDL) based on Functional Living
Index-Emesis (FLIE): Overall 0–120 h.
safety
The overall incidence, type, frequency and intensity of treatment-emergent adverse
events were comparable between the two treatment groups. Among the patients reporting
adverse events, the majority (85%) reported adverse events of mild/moderate intensity.
Of the 94 NEPA-treated patients who experienced a severe adverse event, only 5 (0.7%)
had a severe treatment-related adverse event. The most common treatment-related adverse
events were headache and constipation (Table 3).
Table 3.
Overall summary of adverse events
N (%) of patients with
NEPA (N = 725)
PALO (N = 725)
Overall (N = 1450)
At least one adverse event (AE)
551 (76%)
507 (69.9%)
1058 (73%)
Serious AE
13 (1.8%)
12 (1.7%)
25 (1.7%)
Serious treatment-relateda AE
0
0
0
Any treatment-relateda AE
59 (8.1%)
52 (7.2%)
111 (7.7%)
Most common treatment-relateda AE
Headache
24 (3.3%)
22 (3.0%)
46 (3.2%)
Constipation
15 (2.1%)
15 (2.1%)
30 (2.1%)
Any treatment-relateda AE leading to discontinuation
0
2 (0.3%)
2 (0.1%)
aThose considered by the investigator to be possibly, probably or definitely related
to study drug.
There were no treatment-related adverse events leading to discontinuation, and there
were very few (0.7%) severe and no serious treatment-related adverse events or deaths
for NEPA-treated patients. Changes from baseline in 12-lead ECGs were similar between
treatment groups at each time point.
discussion
NEPA, a novel combination of the new NK1 RA, NETU and best-in-class 5-HT3 RA, PALO,
has been designed to overcome potential barriers hindering antiemetic guideline adherence
by conveniently packaging guideline-recommended agents in a single oral fixed-dose.
A single day 1 dose of NEPA along with DEX only on day 1 seems suitable for prevention
of CINV through the 5 days after chemotherapy.
This large, phase III, registration study was designed to demonstrate the superiority
of NEPA over PALO in chemotherapy-naïve patients receiving AC-based MEC. NEPA significantly
improved CR rates compared with PALO during all phases after chemotherapy, with the
incremental benefit being greatest during the delayed and overall phases. Regardless
of the efficacy end-point, NEPA was consistently superior to PALO during the 5-day
period following chemotherapy. In particular, NEPA resulted in significantly greater
no emesis rates during all phases and no significant nausea and complete protection
rates during the delayed and overall phases. The consistent superiority of NEPA over
PALO across all end points during the delayed phase is particularly opportune, in
that patients are protected during a period which has remained a challenge in most
clinical settings.
Control of delayed nausea does not reach the same level of benefit as that of emesis
and remains a clinical unmet need [2, 3]. Although it was a secondary end point, it
is encouraging that NEPA demonstrated a delayed nausea benefit which was also seen
in the phase II trial in patients receiving cisplatin-based HEC [8], providing additional
support of its efficacy. The utilization of the FLIE instrument confirmed that by
improving control of CINV, NEPA significantly reduced the impact of CINV on patients'
functioning. This was seen consistently in all domains of the FLIE assessment.
As DEX may be associated with a range of side-effects, there is particular interest
in minimizing its dose/frequency, especially in patients who experience DEX-related
side-effects. Consistent with the recommendation by MASCC/ESMO in the AC setting,
DEX was given on day 1 only. Therefore, the complete antiemetic regimen in this study
was administered just before chemotherapy. In a study in a similar population of chemotherapy-naïve
breast cancer patients, a single dose of PALO plus DEX on day 1 showed similar CR
rates as PALO (day 1) plus DEX (day 1–3) [11] (the recommended antiemetic regimen
in AC at the time of the study). The authors speculated that the unique pharmacology
of PALO may have explained the extended protection in the delayed phase, without the
need for multiple day DEX. The response rates seen in the current trial were generally
higher than those seen in prior NK1 RA trials [4] where DEX was administered on day
1 only concomitantly with an older generation 5-HT3 RA. The present result validates
the guideline recommendations of a single day of DEX in patients receiving AC and
provides encouraging evidence that DEX beyond day 1 is not necessary when using NEPA
in patients at higher risk for CINV.
While AC are still classified by some guideline groups as chemotherapy that present
a moderate emetic risk, although separately from other MEC [3], other committees developing
antiemetic guidelines have included AC in the high-risk category [12]. This is a simplification
related to the fact that the same NK1RA/5-HT3RA/DEX treatment is recommended for both
HEC and AC, while, in other MEC, the use of NK1RAs is an option which varies according
to the perceived risk. There is already limited data on how NEPA performs in a non-AC
MEC population [13].
As already demonstrated in the large phase II trial, NEPA was very well tolerated
with a comparable adverse event profile to PALO. There was a very low incidence of
treatment-related adverse events, none of which led to discontinuation and no serious
treatment-related adverse events or deaths for NEPA-treated patients. There were no
cardiac safety concerns for either NEPA or PALO based on cardiac AEs/ECGs.
In conclusion, NEPA resulted in superior prevention of CINV than PALO in patients
receiving MEC. As a combination agent targeting dual antiemetic pathways, a single
dose of NEPA plus DEX offers convenient guideline-based prophylaxis. This provides
an opportunity to overcome barriers interfering with guideline adherence and in doing
so offers promise for improving control of CINV for patients.
funding
This work was supported by Helsinn Healthcare, SA who provided the study drugs and
the funding for this study.
disclosure
The authors have the following conflicts of interest to disclose: MA: consultant for
Amgen, BMS, Celgene, GSK, Helsinn Healthcare, JnJ, Novartis, Merck, Merck Serono,
Pfizer, Pierre Fabre, Roche, Sandoz, Teva and Vifor; received honoraria for symposia
lectures for Amgen, Bayer Schering, Cephalon, Chugai, GSK, Helsinn Healthcare, Hospira,
Ipsen, JnJ OrthoBiotech, Merck, Merck Serono, Novartis, Pfizer, Pierre Fabre, Roche,
Sandoz, Sanofi, Teva and Vifor. HR: currently conducting investigator initiated trial
partially funded by Eisai and provided to UCSF. GR, GR and MEB: employees of Helsinn
Healthcare. MK: advisory board honoraria received from Helsinn Healthcare. LS: consultant
for Eisai and Helsinn Healthcare; on speakers bureau for Eisai. All remaining authors
have declared no conflicts of interest.
Supplementary Material
Supplementary Data