DOPTELET Film-coated tablet Ref.[10005] Active ingredients: Avatrombopag

5.1 Thrombotic/Thromboembolic Complications

DOPTELET is a thrombopoietin (TPO) receptor agonist and TPO receptor agonists have been associated with thrombotic and thromboembolic complications in patients with chronic liver disease or chronic immune thrombocytopenia. In patients with chronic liver disease, thromboembolic events (portal vein thrombosis) occurred in 0.2% (1/430) of patients receiving DOPTELET. In patients with chronic immune thrombocytopenia, thromboembolic events (arterial or venous) occurred in 7% (9/128) of patients receiving DOPTELET.

Consider the potential increased thrombotic risk when administering DOPTELET to patients with known risk factors for thromboembolism, including genetic prothrombotic conditions (e.g., Factor V Leiden, Prothrombin 20210A, Antithrombin deficiency or Protein C or S deficiency).

DOPTELET should not be administered to patients with chronic liver disease or chronic immune thrombocytopenia in an attempt to normalize platelet counts. Follow the dosing guidelines to achieve target platelet counts. Monitor patients receiving DOPTELET for signs and symptoms of thromboembolic events and institute treatment promptly.

The following clinically significant adverse reactions are discussed in detail in other sections of the labeling:

• Thrombotic/Thromboembolic Complications [see Warnings and Precautions (5.1)].

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Patients with Chronic Liver Disease

The safety of DOPTELET was evaluated in two international, identically designed, randomized, double-blind, placebo-controlled trials, ADAPT-1 and ADAPT-2, in which 430 patients with chronic liver disease and thrombocytopenia received either DOPTELET (n=274) or placebo (n=156) daily for 5 days prior to a scheduled procedure, and had 1 post-dose safety assessment. Patients were divided into two groups based on their mean platelet count at baseline:

• Low Baseline Platelet Count Cohort (less than 40 × 10⁹/L) who received DOPTELET 60 mg once daily for 5 days
• High Baseline Platelet Count Cohort (40 to less than 50 × 10⁹/L) who received DOPTELET 40 mg once daily for 5 days

The majority of patients were males (65%) and median subject age was 58 years (ranging from 19-86 years of age). The racial and ethnic distribution was White (60%), Asian (33%), Black (3%), and Other (3%).

The most common adverse reactions (those occurring in ≥3% of patients) in the DOPTELET-treated groups (60 mg or 40 mg) across the pooled data from the two trials are summarized in Table 5.

Table 5. Adverse Reactions with a Frequency ≥3% in Patients with C hronic L iver D isease Treated with DOPTELET – Pooled Data ADAPT-1 and ADAPT-2:

For the Low Baseline Platelet Count Cohort, the incidence of serious adverse reactions was 7% (11/159) in the 60 mg DOPTELET treatment group. For the High Baseline Platelet Count Cohort, the incidence of serious adverse reactions was 8% (9/115) in the 40 mg DOPTELET treatment group. The most common serious adverse reaction reported with DOPTELET was hyponatremia. Two DOPTELET-treated patients (0.7%) developed hyponatremia.

Adverse reactions resulting in discontinuation of DOPTELET were anemia, pyrexia, and myalgia; each was reported in a single (0.4%) patient in the DOPTELET (60 mg) treatment group.

Patients with Chronic Immune Thrombocytopenia

The safety of DOPTELET was evaluated in four clinical trials in patients with chronic immune thrombocytopenia: two Phase 3 trials (one randomized, double-blind, placebo-controlled trial, and one randomized, double-blind, active-controlled trial) and two Phase 2 trials (one randomized, double-blind, placebo-controlled, dose-ranging, trial, and one open-label extension trial) in 161 patients with chronic immune thrombocytopenia in both the double-blind and open-label extension phases.

The pooled safety data from these four clinical trials includes 128 patients who received 2.5 to 40 mg of DOPTELET once daily for a median duration of exposure of 29.1 weeks and had 1 post-dose safety assessment. The majority of patients were female (63%) and median subject age was 50.5 years (ranging from 18-88 years of age). The racial and ethnic distribution was White (84%), Black (6%), Asian (6%) and Other (6%).

The most common adverse reactions (those occurring in ≥10% of patients) in the DOPTELET-treated patients across the pooled safety data from the four trials are summarized in Table 6.

Table 6: Adverse Reactions with a Frequency ≥10% in Patients with Chronic Immune Thrombocytopenia Treated with DOPTELET – Pooled Data from Clinical Trials:

The incidence of serious adverse reactions was 9% (12/128) in the DOPTELET treatment group. Serious adverse reactions reported in more than 1 individual DOPTELET-treated patient included headache, occurring in 1.6% (2/128).

Adverse reactions resulting in discontinuation of DOPTELET that were reported in more than 1 patient included headache, occurring in 1.6% (2/128).

The following adverse reactions have been identified during post approval use of DOPTELET. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Immune System Disorders: Hypersensitivity reactions including pruritus, rash, choking sensation, erythema, pharyngeal edema, pruritus generalized, rash macular, swelling face, and swollen tongue.

7.1 Effect of Other Drugs on DOPTELET in Patients with Chronic Immune Thrombocytopenia

Moderate or Strong Dual Inhibitors of CYP2C9 and CYP3A4

Concomitant use with a moderate or strong dual inhibitor of CYP2C9 and CYP3A4 increases avatrombopag AUC [see Clinical Pharmacology (12.3)], which may increase the risk of DOPTELET toxicities. Reduce the starting dosage of DOPTELET when used concomitantly with a moderate or strong dual inhibitor of CYP2C9 and CYP3A4 (see Table 4) [see Dosage and Administration (2.3)].

In patients starting moderate or strong dual inhibitors of CYP2C9 and CYP3A4 while receiving DOPTELET, monitor platelet counts and adjust DOPTELET dose as necessary (see Table 3) [see Dosage and Administration (2.2)].

Moderate or Strong Dual Inducers of CYP2C9 and CYP3A4

Concomitant use with a moderate or strong dual inducer of CYP2C9 and CYP3A4 decreases avatrombopag AUC [see Clinical Pharmacology (12.3)] which may reduce DOPTELET efficacy. Increase the recommended starting dosage of DOPTELET when used concomitantly with a moderate or strong dual inducer of CYP2C9 and CYP3A4 (see Table 4) [see Dosage and Administration (2.3)].

In patients starting moderate or strong dual inducers of CYP2C9 and CYP3A4 while receiving DOPTELET, monitor platelet counts and adjust dose as necessary (see Table 3) [see Dosage and Administration (2.2)].

Patients with Chronic Liver Disease

No dosage adjustments are required for patients with chronic liver disease.

Risk Summary

Based on findings from animal reproduction studies, DOPTELET may cause fetal harm when administered to a pregnant woman (see Data). The available data on DOPTELET in pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes. In animal reproduction studies, oral administration of avatrombopag resulted in adverse developmental outcomes when administered during organogenesis in rabbits and during organogenesis and the lactation period in rats. However, these findings were observed at exposures based on an AUC substantially higher than the AUC observed in patients at the maximum recommended dose of 60 mg once daily. Advise pregnant women of the potential risk to a fetus.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and of miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

In embryo-fetal development studies, avatrombopag was administered during organogenesis at doses of 100, 300, and 1000 mg/kg/day in rats and doses of 100, 300, and 600 mg/kg/day in rabbits. Minimal decreases in fetal weights were observed in rats at the maternally toxic dose of 1000 mg/kg/day with exposures 190 times the human exposure based on AUC. Spontaneous abortions were observed at all doses tested in rabbits and were associated with decreased body weights and food consumption at 300 and 600 mg/kg/day; exposures at the lowest dose of 100 mg/kg/day were 10 times the AUC in patients at the maximum recommended dose of 60 mg once daily. There were no embryo-fetal effects in rats administered avatrombopag at doses up to 100 mg/kg/day (53 times the human exposure based on AUC) or rabbits administered avatrombopag at doses up to 600 mg/kg (35 times the human exposure based on AUC).

In pre- and postnatal development studies in rats, avatrombopag was administered during both the organogenesis and lactation periods at doses ranging from 5 to 600 mg/kg/day. Doses of 100, 300, and 600 mg/kg/day caused maternal toxicity leading to total litter losses, decreased body weight in pups, and increased pup mortality, with the majority of the pup mortality occurring between postnatal days 14 to 21. At a dose of 50 mg/kg/day that did not produce clear maternal toxicity, avatrombopag caused increased pup mortality from postnatal days 4 to 21, and mortality continued through postnatal day 25. The 50 mg/kg/day dose also decreased body weight gain in the pups, resulting in a delay in sexual maturation. There were no effects on behavioral or reproductive functions in the offspring. The 50 mg/kg/day dose resulted in maternal exposures 43 times and pup exposures approximately 3 times the AUC observed in patients at the maximum recommended dose of 60 mg once daily.

Risk Summary

There is no information regarding the presence of avatrombopag in human milk, the effects on the breastfed child, or the effects on milk production. Avatrombopag was present in the milk of lactating rats. When a drug is present in animal milk, it is likely the drug will be present in human milk. Due to the potential for serious adverse reactions in a breastfed child from DOPTELET, breastfeeding is not recommended during treatment with DOPTELET and for at least 2 weeks after the last dose (see Clinical Considerations).

Clinical Considerations

Minimizing Exposure

A lactating woman receiving DOPTELET for brief periods, such as prior to an invasive procedure, should interrupt breastfeeding and pump and discard breastmilk during treatment and for two weeks after the last dose of DOPTELET in order to minimize exposure to a breastfed child. Advise lactating women receiving chronic DOPTELET therapy not to breastfeed during treatment with DOPTELET and for at least 2 weeks after the last dose.

Safety and effectiveness in pediatric patients have not been established.

In a 10-week juvenile toxicology study in rats, avatrombopag was administered at doses ranging from 20 to 300 mg/kg/day. There were no test article-related mortality or clinical signs at doses up to 300 mg/kg/day. In the stomach, dose-dependent degeneration, regenerative hyperplasia, and atrophy of the glandular epithelium occurred at 100 and 300 mg/kg/day; exposures at 100 mg/kg/day in male rats were 14 times the AUC in patients at the recommended dose of 60 mg once daily. An increased incidence of background focal mineralization was also observed in the kidneys of females at 300 mg/kg/day (female rat exposure was 50 times the human exposure based on AUC at the 60 mg daily dose).

Clinical studies of DOPTELET did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.