AVAPRITINIB Drug Interactions: What You Need to Know

INTERACTIONS Strong and Moderate CYP3A Inhibitors : Avoid coadministration of AYVAKIT with strong and moderate CYP3A inhibitors. If coadministration of AYVAKIT with a moderate inhibitor cannot be avoided, reduce dose of AYVAKIT in patients with GIST or AdvSM. ( 2.6 , 7.1 ) Strong and Moderate CYP3A Inducers : Avoid coadministration of AYVAKIT with strong and moderate CYP3A inducers. ( 7.1 ) Hormonal contraceptives containing ethinyl estradiol : See full prescribing information for dose-specific recommendations for concomitant use ( 7.2 )

7.1 Effects of Other Drugs on AYVAKIT Strong and Moderate CYP3A Inhibitors Coadministration of AYVAKIT with a strong or moderate CYP3A inhibitor increases avapritinib plasma concentrations <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span>, which may increase the incidence and severity of adverse reactions of AYVAKIT. Avoid coadministration of AYVAKIT with strong or moderate CYP3A inhibitors. If coadministration of AYVAKIT with a moderate CYP3A inhibitor cannot be avoided, reduce the dose of AYVAKIT <span class="opacity-50 text-xs">[see Dosage and Administration (2.6) ]</span>. Strong and Moderate CYP3A Inducers Coadministration of AYVAKIT with a strong or moderate CYP3A inducer decreases avapritinib plasma concentrations <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> , which may decrease efficacy of AYVAKIT. Avoid coadministration of AYVAKIT with strong or moderate CYP3A inducers.

7.2 Effects of AYVAKIT on Other Drugs Coadministration of AYVAKIT with ethinyl estradiol-containing contraceptives may increase the exposure of ethinyl estradiol, which may lead to increased risk of ethinyl estradiol-associated adverse reactions <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> . If the patient is unable to use or tolerate an effective nonhormonal contraceptive or an effective hormonal contraceptive without estrogen, use a formulation of ethinyl estradiol containing 20 mcg or less unless a higher dose is necessary.

None. None. ( 4 )

AND PRECAUTIONS Intracranial Hemorrhage : Permanently discontinue for any occurrence of any grade. ( 2.5 , 5.1 )

Cognitive

Effects : A broad spectrum of cognitive adverse reactions can occur in patients receiving AYVAKIT. In patients with GIST, AdvSM, or ISM depending on the severity, continue AYVAKIT at same dose, withhold and then resume at same or reduced dose upon improvement, or permanently discontinue. ( 2.5 , 5.2 ) Photosensitivity: May cause photosensitivity reactions. Advise patients to limit direct ultraviolet exposure. ( 5.3 ) Embryo-Fetal Toxicity : Can cause fetal harm. Advise females and males of reproductive potential of the potential risk to a fetus and to use effective contraception. ( 5.4 , 8.1 , 8.3 )

5.1 Intracranial Hemorrhage Serious intracranial hemorrhage may occur with AYVAKIT treatment; fatal events occurred in less than 1% of patients. Overall, intracranial hemorrhage (e.g., subdural hematoma, intracranial hemorrhage, and cerebral hemorrhage) occurred in 2.9% of the 749 patients with GIST or AdvSM who received AYVAKIT in clinical trials. No events of intracranial hemorrhage occurred in the 246 patients with ISM who received any dose of AYVAKIT in the PIONEER study . Monitor patients closely for risk factors of intracranial hemorrhage which may include history of vascular aneurysm, intracranial hemorrhage or cerebrovascular accident within the prior year, concomitant use of anticoagulant drugs, or thrombocytopenia. Symptoms of intracranial hemorrhage may include headache, nausea, vomiting, vision changes, or altered mental status. Advise patients to seek immediate medical attention for signs or symptoms of intracranial hemorrhage. Permanently discontinue AYVAKIT if intracranial hemorrhage of any grade occurs <span class="opacity-50 text-xs">[see Dosage and Administration (2.5) ]</span> .

Gastrointestinal Stromal Tumors

Intracranial hemorrhage occurred in 3 of 267 patients (1.1%). Two (0.7%) of the events were Grade ≥ 3 and resulted in discontinuation of study drug. Events of intracranial hemorrhage occurred in a range from 1.7 months to 19.3 months after initiating AYVAKIT.

Advanced Systemic

Mastocytosis In patients with AdvSM who received AYVAKIT at 200 mg daily, intracranial hemorrhage occurred in 2 of 75 patients (2.7%) who had platelet counts ≥ 50 × 10 9 /L prior to initiation of therapy and in 3 of 80 patients (3.8%) regardless of platelet counts. In patients with AdvSM, a platelet count must be performed prior to initiating therapy; AYVAKIT is not recommended in patients with AdvSM with platelet counts < 50 × 10 9 /L. Following treatment initiation, platelet counts must be performed every 2 weeks for the first 8 weeks regardless of baseline platelet count.

After

8 weeks of treatment, monitor platelet counts every 2 weeks (or more frequently as clinically indicated) if values are less than 75 × 10 9 /L, every 4 weeks if values are between 75 and 100 × 10 9 /L, and as clinically indicated if values are greater than 100 × 10 9 /L. Manage platelet counts of < 50 × 10 9 /L by treatment interruption or dose-reduction of AYVAKIT. Platelet support may be necessary [see Dosage and Administration (2.5) ] . Dose-interruptions and dose-reductions for thrombocytopenia occurred in 20% and 22% of AYVAKIT-treated patients, respectively. Thrombocytopenia was generally reversible by reducing or interrupting AYVAKIT.

5.2 Cognitive Effects Cognitive adverse reactions can occur in patients receiving AYVAKIT. These cognitive adverse reactions occurred in 33% of the 995 patients with GIST, AdvSM or ISM who received AYVAKIT in clinical trials. These adverse reactions were managed with dose interruption and/or reduction when needed. Overall, 10% led to dose interruptions, 7% led to dose reductions and 2.2% led to permanent discontinuation of AYVAKIT treatment in patients with GIST, AdvSM or ISM. Depending on the severity and indication, withhold AYVAKIT and then resume at the same dose or at a reduced dose upon improvement, or permanently discontinue AYVAKIT <span class="opacity-50 text-xs">[see Dosage and Administration (2.5) ]</span> .

Indolent Systemic Mastocytosis

Cognitive adverse reactions occurred in 7.8% of patients with ISM who received AYVAKIT + best supportive care versus 7% of patients who received placebo + best supportive care in the PIONEER study; <1% were Grade 3. The median time to onset of the first cognitive adverse reaction was 2.3 months (range: 0 to 5.4 months). Median time to improvement to Grade 1 or complete resolution was 2.1 months (range: 0.4 to 2.1 months).

Gastrointestinal Stromal Tumors

Cognitive adverse reactions occurred in 41% of 601 patients with GIST who received AYVAKIT; 5% were Grade ≥ 3. Memory impairment occurred in 21% of patients; <1% of these events were Grade 3. Cognitive disorder occurred in 12% of patients; 1.2% of these events were Grade 3. Confusional state occurred in 6% of patients; <1% of these events were Grade 3. Amnesia occurred in 3% of patients; <1% of these events were Grade 3. Somnolence and speech disorder occurred in 2% of patients; none of these events were Grade 3. Other events occurred in less than 2% of patients. The median time to onset of the first cognitive adverse reaction was 8.4 weeks (range: 1 day to 4 years). Among patients who experienced a cognitive effect of Grade 2 or worse (impacting activities of daily living), the median time to improvement to Grade 1 or complete resolution was 7.9 weeks. Overall, 2.7% of all patients who received AYVAKIT required permanent discontinuation for a cognitive adverse reaction, 13.5% required a dosage interruption, and 8.5% required dose reduction.

Advanced Systemic Mastocytosis

Cognitive adverse reactions occurred in 28% of 148 patients with AdvSM who received AYVAKIT; 3% were Grade ≥ 3. Memory impairment occurred in 16% of patients; all events were Grade 1 or 2. Cognitive disorder occurred in 10% of patients; <1% of these events were Grade 3. Confusional state occurred in 6% of patients; <1% of these events were Grade 3. Other events occurred in less than 2% of patients. The median time to onset of the first cognitive adverse reaction was 13.3 weeks (range: 1 day to 1.8 years). Among patients who experienced a cognitive effect of Grade 2 or worse (impacting activities of daily living), the median time to improvement to Grade 1 or complete resolution was 8.1 weeks. Overall, 2% of all patients who received AYVAKIT required permanent discontinuation for a cognitive adverse reaction, 8.1% required a dosage interruption, and 8.8% required dose reduction. 5. 3 Photosensitivity AYVAKIT may cause photosensitivity reactions. In all patients treated with AYVAKIT in clinical trials (n=1049), photosensitivity reactions occurred in 2.5% of patients. Advise patients to limit direct ultraviolet exposure during treatment with AYVAKIT and for one week after discontinuation of treatment.

5.4 Embryo-Fetal Toxicity Based on findings from animal studies and its mechanism of action, AYVAKIT can cause fetal harm when administered to pregnant women. Oral administration of avapritinib during the period of organogenesis was teratogenic and embryotoxic in rats at exposures approximately 31.4, 6.3 and 2.7 times the human exposure based on area under the curve (AUC) at the 25 mg, 200 mg, and 300 mg dose, respectively. Advise pregnant women of the potential risk to a fetus. Advise females and males of reproductive potential to use effective contraception during treatment with AYVAKIT and for 6 weeks after the final dose <span class="opacity-50 text-xs">[see Use in Specific Populations (8.1 , 8.3) ]</span> .