Locally Advanced or Metastatic Breast Cancer
INAVO120
The safety of ITOVEBI was evaluated in a randomized, double-blind, placebo-controlled study (INAVO120) in 324 patients with PIK3CA-mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer [see Clinical Studies (14.1)].
Patients received either ITOVEBI 9 mg (n=162) or placebo (n=162) with palbociclib and fulvestrant. The median duration of treatment with ITOVEBI was 9 months (range: 0 to 39 months) in the ITOVEBI with palbociclib and fulvestrant arm.
Serious adverse reactions occurred in 24% of patients who received ITOVEBI with palbociclib and fulvestrant. Serious adverse reactions in ≥ 1% of patients included anemia (1.9%), diarrhea (1.2%), and urinary tract infection (1.2%).
Fatal adverse reactions occurred in 3.7% of patients who received ITOVEBI with palbociclib and fulvestrant, including (0.6% each) acute coronary syndrome, cerebral hemorrhage, cerebrovascular accident, COVID-19 infection, and gastrointestinal hemorrhage.
Permanent discontinuation of ITOVEBI due to an adverse reaction occurred in 6% of patients. Adverse reactions which resulted in permanent discontinuation of ITOVEBI included hyperglycemia (1.2%), and (0.6% each) stomatitis, gastric ulcer, intestinal perforation, anal abscess, increased ALT, decreased weight, bone pain, musculoskeletal pain, transitional cell carcinoma, and acute kidney injury.
Dosage interruptions of ITOVEBI due to an adverse reaction occurred in 69% of patients. Adverse reactions which required dosage interruption in ≥ 2% of patients included hyperglycemia (28%), neutropenia (23%), COVID-19 infection (16%), stomatitis (10%), diarrhea (7%), thrombocytopenia (4.9%), anemia (4.3%), upper respiratory tract infection (4.3%), decreased white blood cell count (3.7%), pyrexia (3.1%), nausea (2.5%), and fatigue (2.5%).
Dose reductions of ITOVEBI due to adverse reactions occurred in 14% of patients. Adverse reactions which required dose reduction of ITOVEBI in ≥ 2% of patients were stomatitis (3.7%) and hyperglycemia (2.5%).
The most common (≥ 20%) adverse reactions, including laboratory abnormalities, were decreased neutrophils, decreased hemoglobin, increased fasting glucose, decreased platelets, decreased lymphocytes, stomatitis, diarrhea, decreased calcium, fatigue, decreased potassium, increased creatinine, increased ALT, nausea, decreased sodium, decreased magnesium, rash, decreased appetite, COVID-19 infection, and headache.
Adverse reactions and laboratory abnormalities in INAVO120 are summarized in Table 3 and Table 4, respectively. Patient-reported symptoms are summarized in Table 5.
Table 3: Adverse Reactions (≥ 10% with ≥ 5% [All Grades] or ≥ 2% [Grade 3-4] Higher Incidence in the ITOVEBI Arm) in INAVO120| Adverse Reaction | ITOVEBI + Palbociclib + Fulvestrant N=162 | Placebo + Palbociclib + Fulvestrant N=162 |
|---|
All Grades (%) | Grade 3-4 (%) | All Grades (%) | Grade 3-4 (%) |
|---|
| Gastrointestinal Disorders |
| Stomatitis Includes aphthous ulcer, glossitis, glossodynia, lip ulceration, mouth ulceration, mucosal inflammation, and stomatitis. | 51 | 6 | 27 | 0 |
| Diarrhea | 48 | 3.7 | 16 | 0 |
| Nausea | 28 | 0.6 | 17 | 0 |
| Vomiting | 15 | 0.6 | 4.9 | 1.2 |
| General Disorders and Administration Site Conditions |
| Fatigue | 38 | 1.9 | 25 | 1.2 |
| Skin and Subcutaneous Tissue Disorders |
| Rash | 26 | 0 | 19 | 0 |
| Alopecia | 19 | 0 | 6 | 0 |
| Dry skin Includes dry skin, skin fissures, xerosis, and xeroderma. | 13 | 0 | 4.3 | 0 |
| Metabolism and Nutrition Disorders |
| Decreased appetite | 24 | 0 | 9 | 0 |
| Infections and Infestations |
| COVID-19 infection | 23 | 1.9 | 10 | 0.6 |
| Urinary tract infection | 15 | 1.2 | 9 | 0 |
| Nervous System Disorders |
| Headache | 22 | 0 | 14 | 0 |
| Investigations |
| Decreased weight | 17 | 3.7 | 0.6 | 0 |
Clinically relevant adverse reactions occurring in < 10% of patients who received ITOVEBI in combination with palbociclib and fulvestrant included abdominal pain, dry eye, dysgeusia, and dyspepsia.
Table 4: Select Laboratory Abnormalities (≥ 10% with a ≥ 2% [All Grades or Grade 3-4] Higher Incidence in the ITOVEBI Arm) in INAVO120| Laboratory Abnormality | ITOVEBI + Palbociclib + Fulvestrant The denominator used to calculate the rate varied from 122 to 160 based on the number of patients with a baseline value and at least one post-treatment value. | Placebo + Palbociclib + Fulvestrant The denominator used to calculate the rate varied from 131 to 161 based on the number of patients with a baseline value and at least one post-treatment value. |
|---|
All Grades (%) | Grade 3-4 (%) | All Grades (%) | Grade 3-4 (%) |
|---|
| ALT = alanine aminotransferase |
| Hematology |
| Neutrophils (total, absolute) decreased | 95 | 82 | 97 | 79 |
| Hemoglobin decreased | 88 | 8 | 85 | 2.5 |
| Platelets decreased | 84 | 16 | 71 | 3.7 |
| Lymphocytes (absolute) decreased | 72 | 9 | 68 | 14 |
| Chemistry |
| Glucose (fasting) increased Grading according to CTCAE version 4.03. | 85 | 12 | 43 | 0 |
| Calcium decreased | 42 | 3.1 | 32 | 3.7 |
| Potassium decreased | 38 | 6 | 21 | 0.6 |
| Creatinine increased | 38 | 1.9 | 30 | 1.2 |
| ALT increased | 34 | 3.1 | 29 | 1.2 |
| Sodium decreased | 28 | 2.5 | 19 | 2.5 |
| Magnesium decreased | 27 | 0.6 | 21 | 0 |
| Lipase (fasting) increased | 16 | 1.4 | 7 | 0 |
In INAVO120, patient-reported symptomatic toxicities (i.e., diarrhea, nausea, vomiting, fatigue, mouth sores, decreased appetite, and rash) were assessed via the Patient-Reported Outcomes – Common Terminology Criteria for Adverse Events (PRO-CTCAE) at baseline, every two weeks through Cycle 3 Day 15, and then Day 1 of every other 28-day cycle until treatment discontinuation.
Completion rates in both arms were > 90% at baseline and > 80% at subsequent time points where > 50% of randomized patients were on treatment.
Table 5: Patient Reported Symptoms Assessed by PRO-CTCAE in INAVO120| ITOVEBI+P+F = ITOVEBI with palbociclib and fulvestrant arm; Placebo+P+F = placebo with palbociclib and fulvestrant arm. |
| Symptom (Attribute) The symptom attribute scoring is defined by amount/frequency/severity with a score of 0 = 'not at all'/'never'/'none'; 1 = 'a little bit'/'rarely'/'mild'; 2 = 'somewhat'/'occasionally'/'moderate'; 3 = 'quite a bit'/'frequently'/'severe'; 4 = 'very much'/'almost constantly'/'very severe'. | Any Symptom Before Treatment (%) The percentage of patients whose symptom score before treatment was 1-4. | Any Worsening on Treatment (%) The percentage of patients whose symptom score increased during treatment, with respect to their score before treatment. | Worsening to Score 3 or 4 (%) The percentage of patients whose symptom score increased to 3 or 4 during treatment, with respect to their score before treatment. |
ITOVEBI + P + F (N=148) | Placebo + P + F (N=152) | ITOVEBI + P + F (N=148) | Placebo + P + F (N=152) | ITOVEBI + P + F (N=148) | Placebo + P + F (N=152) |
| Diarrhea (frequency), % | 23 | 15 | 78 | 49 | 32 | 8 |
| Nausea (frequency), % | 21 | 21 | 59 | 50 | 20 | 11 |
| Vomiting (frequency), % | 9 | 6 | 35 | 26 | 6 | 3 |
| Fatigue (severity), % | 72 | 69 | 72 | 58 | 32 | 22 |
| Mouth sores (severity), % | 11 | 14 | 74 | 52 | 30 | 9 |
| Decreased appetite (severity), % | 38 | 27 | 78 | 55 | 26 | 12 |
| Symptom (Attribute) | Baseline Presence | Post-baseline Presence |
ITOVEBI+P+F (N=148) | Placebo +P+F (N=152) | ITOVEBI+P+F (N=152) | Placebo+P+F (N=158) |
| Rash (yes), % | 5 | 5 | 50 | 38 |
Patient-reported overall side-effect impact was assessed using the Modified Bother Item (MBI). Patients provided a response to "I am bothered by side effects of treatment," and at baseline the proportion of patients with MBI responses of "not at all" were 70% in the ITOVEBI with palbociclib and fulvestrant arm and 76% in the placebo with palbociclib and fulvestrant arm. At Cycle 2 Day 15, the proportion of patients with MBI responses of "not at all" were 25% in the ITOVEBI with palbociclib and fulvestrant arm and 53% in the placebo with palbociclib and fulvestrant arm. Through 31 cycles of treatment, patients in the ITOVEBI with palbociclib and fulvestrant arm reported more side effect bother compared to the placebo with palbociclib and fulvestrant arm.
Risk Summary
ITOVEBI is used in combination with palbociclib and fulvestrant. Refer to the Full Prescribing Information of palbociclib and fulvestrant for pregnancy information.
Based on animal data and its mechanism of action, ITOVEBI can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)]. There are no available data on the use of ITOVEBI in pregnant women to inform a drug-associated risk. In an animal reproduction study, oral administration of inavolisib to pregnant rats during the period of organogenesis caused adverse developmental outcomes, including embryo-fetal mortality, structural abnormalities, and alterations to growth at maternal exposures approximately equivalent to the human exposure at the recommended dose of 9 mg/day based on AUC (see Data). Advise pregnant women and females of reproductive potential of the potential risk to a fetus.
The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects is 2% to 4% and of miscarriage is 15% to 20% of clinically recognized pregnancies in the U.S. general population.
Data
Animal Data
In an embryo-fetal development study, pregnant rats received oral doses of inavolisib up to 6 mg/kg/day during the period of organogenesis. Administration of doses ≥ 2 mg/kg/day resulted in decreases in fetal body weight and placental weight, post-implantation loss, lower fetal viability, fetal malformations (including kyphosis of vertebral column, fused thoracic arch, microphthalmia) and variations (including dilated renal pelvis, short supernumerary rib, wavy rib). At a dose of 2 mg/kg/day, maternal exposures were 0.9 times the human exposure at the recommended dose of 9 mg/day based on AUC.
Risk Summary
ITOVEBI is used in combination with palbociclib and fulvestrant. Refer to the Full Prescribing Information of palbociclib and fulvestrant for lactation information.
There are no data on the presence of inavolisib or its metabolites in human milk, its effects on milk production or a breastfed child. Because of the potential for serious adverse reactions in a breastfed child, advise lactating women to not breastfeed during treatment with ITOVEBI and for 1 week after the last dose.
Pregnancy Testing
Verify pregnancy status in females of reproductive potential prior to initiating treatment with ITOVEBI.
Contraception
Females
Advise females of reproductive potential to use effective non-hormonal contraception during treatment with ITOVEBI and for 1 week after the last dose.
Males
Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ITOVEBI and for 1 week after the last dose.
Infertility
Based on animal studies, ITOVEBI may impair fertility in females and males of reproductive potential [see Nonclinical Toxicology (13.1)].
Exposure-Response Relationships
The exposure-response relationship for the efficacy of inavolisib has not been fully characterized. Inavolisib time course of pharmacodynamic response is unknown. Higher systemic exposure of inavolisib was associated with higher incidence of Grade ≥ 2 anemia, Grade ≥ 2 hyperglycemia, and inavolisib dosage modifications due to adverse reactions.
Cardiac Electrophysiology
At the recommended approved dosage, a mean increase in the QTc interval of > 20 ms is unlikely.
Absorption
Inavolisib absolute oral bioavailability is 76%. Inavolisib steady-state median (min, max) time to maximum plasma concentration (Tmax) is 3 hours (0.5, 4 hours).
Effect of Food
No clinically significant differences in inavolisib pharmacokinetics were observed following administration of inavolisib with a high-fat meal (approximately 1,000 calories, 50% fat).
Distribution
Inavolisib apparent (oral) volume of distribution is 155 L (26%). Inavolisib plasma protein binding is 37% and is not concentration-dependent in vitro. Inavolisib blood-to-plasma ratio is 0.8.
Elimination
Inavolisib elimination half-life is 15 hours (24%) with a total clearance of 8.8 L/hr (29%).
Metabolism
Inavolisib is primarily metabolized by hydrolysis. In vitro, inavolisib was minimally metabolized by CYP3A.
Excretion
Following oral administration of a single radiolabeled dose, 49% of the administered dose was recovered in urine (40% unchanged) and 48% in feces (11% unchanged).
Specific Populations
No clinically significant differences in the pharmacokinetics of inavolisib were observed based on age (27 to 85 years), sex, race (Asian or White), body weight (39 to 159 kg), or mild hepatic impairment (total bilirubin > ULN to ≤ 1.5 × ULN or AST > ULN and total bilirubin ≤ ULN). The effect of moderate to severe hepatic impairment on inavolisib pharmacokinetics is unknown.
Patients with Renal Impairment
Inavolisib AUC was 73% higher in patients with moderate renal impairment compared to patients with normal renal function (eGFR ≥ 90 mL/min).
No clinically significant differences in the pharmacokinetics of inavolisib were observed in patients with mild renal impairment compared to patients with normal renal function. The effect of severe renal impairment (eGFR < 30 mL/min) on the pharmacokinetics of inavolisib is unknown.
Drug Interaction Studies
Clinical Studies and Model-Informed Approaches
Proton Pump Inhibitors: No clinically significant difference in steady-state inavolisib pharmacokinetics were observed based upon concomitant use of a proton pump inhibitor (lansoprazole, omeprazole, esomeprazole, pantoprazole, or rabeprazole).
In Vitro Studies
CYP450 Enzymes: Inavolisib induces CYP3A and CYP2B6. Inavolisib is a time-dependent inhibitor of CYP3A. Inavolisib does not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP2D6.
Transporter Systems: Inavolisib is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), but is not a substrate of OATP1B1, OATP1B3, OCT1, OCT2, MATE1, MATE2K, OAT1, OAT2. Inavolisib does not inhibit P-gp, BCRP, OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, MATE1, or MATE2K.
INAVO120
INAVO120 (NCT04191499) was a randomized (1:1), double-blind, placebo-controlled trial evaluating the efficacy of ITOVEBI in combination with palbociclib and fulvestrant in adult patients with endocrine-resistant PIK3CA-mutated, HR-positive, HER2-negative (defined as IHC 0 or 1+, or IHC 2+/ISH-), locally advanced or metastatic breast cancer whose disease progressed during or within 12 months of completing adjuvant endocrine therapy and who have not received prior systemic therapy for locally advanced or metastatic disease. Randomization was stratified by presence of visceral disease (yes or no), endocrine resistance (primary or secondary), and geographic region (North America/Western Europe, Asia, other).
Primary endocrine resistance was defined as relapse while on the first 2 years of adjuvant endocrine therapy (ET) and secondary endocrine resistance was defined as relapse while on adjuvant ET after at least 2 years or relapse within 12 months of completing adjuvant ET.
Patients were required to have a HbA1C < 6% and fasting blood glucose < 126 mg/dL. The study excluded patients with Type 1 diabetes mellitus or Type 2 diabetes mellitus requiring ongoing anti-hyperglycemic treatment at the start of study treatment.
PIK3CA mutation status was prospectively determined in a central laboratory using the FoundationOne® Liquid CDx assay on plasma-derived circulating tumor DNA (ctDNA) or in local laboratories using various validated polymerase chain reaction (PCR) or next-generation sequencing (NGS) assays on tumor tissue or plasma. All patients were required to provide both a freshly collected pre-treatment blood sample and a tumor tissue sample for central evaluation and determination of PIK3CA mutation(s) status.
Patients received either ITOVEBI 9 mg (n=161) or placebo (n=164) orally once daily, in combination with palbociclib 125 mg orally once daily for 21 consecutive days followed by 7 days off treatment to comprise a cycle of 28 days, and fulvestrant 500 mg administered intramuscularly on Cycle 1, Days 1 and 15, and then on Day 1 of every 28-day cycle. Patients received treatment until disease progression or unacceptable toxicity. In addition, all pre/perimenopausal women and men received an LHRH agonist throughout therapy.
The baseline demographic and disease characteristics were: median age 54 years (range: 27 to 79 years); 98% female, of which 39% were pre/perimenopausal; 59% White, 38% Asian, 2.5% unknown, 0.6% Black or African American; 6% Hispanic or Latino; and Eastern Cooperative Oncology Group (ECOG) performance status of 0 (63%) or 1 (36%). Tamoxifen (57%) and aromatase inhibitors (50%) were the most commonly used adjuvant endocrine therapies. Sixty-four percent of patients were considered to have secondary endocrine resistance. Eighty-three percent of patients had received prior chemotherapy (in the neo/adjuvant setting) and 1.2% of patients had been treated with a CDK4/6 inhibitor.
The major efficacy outcome measure was investigator (INV)-assessed progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Additional efficacy outcome measures included overall survival (OS), INV-assessed objective response rate (ORR), and INV-assessed duration of response (DOR).
Efficacy results are summarized in Table 6 and Figure 1. INV-assessed PFS results were supported by consistent results from a blinded independent central review (BICR) assessment. At the time of the PFS analysis, OS data were not mature with 30% deaths in the overall population.
Table 6: Efficacy Results in Patients with Locally Advanced or Metastatic Breast Cancer in INAVO120| Efficacy Endpoint | ITOVEBI + Palbociclib + Fulvestrant N=161 | Placebo + Palbociclib + Fulvestrant N=164 |
|---|
| CI = confidence interval; CR = complete response; DOR = duration of response; PR = partial response |
| Progression-Free Survival, |
| Patients with event, n (%) | 82 (51) | 113 (69) |
| Median, months (95% CI) | 15.0 (11.3, 20.5) | 7.3 (5.6, 9.3) |
| Hazard ratio (95% CI) | 0.43 (0.32, 0.59) |
| p-value | < 0.0001 |
| Objective Response Rate,, Based on confirmed ORR. |
| Patients with CR or PR, n (%) | 94 (58) | 41 (25) |
| 95% CI | (50, 66) | (19, 32) |
| Duration of Response |
| Median DOR, months (95% CI) | 18.4 (10.4, 22.2) | 9.6 (7.4, 16.6) |
Figure 1: Kaplan-Meier Curve for Investigator-Assessed Progression-Free Survival in INAVO120
Hyperglycemia
Advise patients that ITOVEBI may cause hyperglycemia and the need to monitor fasting glucose levels periodically during therapy. Advise patients to contact their healthcare provider immediately for signs and symptoms of hyperglycemia (e.g., excessive thirst, urinating more often, blurred vision, mental confusion, difficulty breathing, or increased appetite with weight loss) [see Warnings and Precautions (5.1)].
Stomatitis
Advise patients that ITOVEBI may cause stomatitis, which may be severe, and to notify their healthcare provider if they develop symptoms of stomatitis (e.g., painful redness, swelling, or sores in the mouth) [see Warnings and Precautions (5.2)].
Diarrhea
Advise patients that ITOVEBI may cause diarrhea, which may be severe, and to start antidiarrheal treatment, increase oral fluids, and notify their healthcare provider if diarrhea occurs while taking ITOVEBI [see Warnings and Precautions (5.3)].
Embryo-Fetal Toxicity
- Inform pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females to inform their healthcare provider of a known or suspected pregnancy [see Warnings and Precautions (5.4) and Use in Specific Populations (8.1)].
- Advise females of reproductive potential to use effective non-hormonal contraception during treatment with ITOVEBI and for 1 week after the last dose [see Use in Specific Populations (8.3)].
- Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ITOVEBI and for 1 week after the last dose [see Use in Specific Populations (8.3)].
- Refer to the Full Prescribing Information of palbociclib and fulvestrant for pregnancy and contraception information.
Lactation
Advise women not to breastfeed during treatment with ITOVEBI and for 1 week after the last dose [see Use in Specific Populations (8.2)]. Refer to the Full Prescribing Information of palbociclib and fulvestrant for lactation information.
Infertility
Advise females and males of reproductive potential that ITOVEBI may impair fertility [see Use in Specific Populations (8.3)]. Refer to the Full Prescribing Information of palbociclib and fulvestrant for infertility information.
Dosing
- Instruct patients to take ITOVEBI at approximately the same time each day [see Dosage and Administration (2.3)].
- Instruct patients that if a dose of ITOVEBI is missed, to take the missed dose as soon as possible within 9 hours. After more than 9 hours, skip the dose and take the next dose at the scheduled time [see Dosage and Administration (2.3)].
- Instruct patients that if vomiting occurs after taking the ITOVEBI dose, do not take an additional dose on that day. Resume the usual dosing schedule the next day [see Dosage and Administration (2.3)].
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