1.1 Relapsed Chronic Lymphocytic Leukemia

Zydelig is indicated, in combination with rituximab, for the treatment of patients with relapsed chronic lymphocytic leukemia (CLL) for whom rituximab alone would be considered appropriate therapy due to other co-morbidities.

1.2 Relapsed Follicular B-cell non-Hodgkin Lymphoma

Zydelig is indicated for the treatment of patients with relapsed follicular B-cell non-Hodgkin lymphoma (FL) who have received at least two prior systemic therapies.

Accelerated approval was granted for this indication based on Overall Response Rate [see Clinical Studies (14.2)]. An improvement in patient survival or disease related symptoms has not been established. Continued approval for this indication may be contingent upon verification of clinical benefit in confirmatory trials.

1.3 Relapsed Small Lymphocytic Lymphoma

Zydelig is indicated for the treatment of patients with relapsed small lymphocytic lymphoma (SLL) who have received at least two prior systemic therapies.

Accelerated approval was granted for this indication based on Overall Response Rate [see Clinical Studies (14.3)]. An improvement in patient survival or disease related symptoms has not been established. Continued approval for this indication may be contingent upon verification of clinical benefit in confirmatory trials.

2.1 Recommended Dosage

The recommended maximum starting dose of Zydelig is 150 mg administered orally twice daily.

Zydelig can be taken with or without food. Tablets should be swallowed whole.

Continue treatment until disease progression or unacceptable toxicity. The optimal and safe dosing regimen for patients who receive treatment longer than several months is unknown.

2.2 Dose Modification

See Table 1 for dose modification instructions for specific toxicities related to Zydelig. For other severe or life-threatening toxicities related to Zydelig, withhold drug until toxicity is resolved. If resuming Zydelig after interruption for other severe or life-threatening toxicities, reduce the dose to 100 mg twice daily. Discontinue Zydelig permanently for recurrence of other severe or life-threatening Zydelig-related toxicity upon rechallenge.

No dose modification is required for lymphocytosis, which has been observed in some patients taking Zydelig. This observed lymphocytosis is a pharmacodynamic effect and should not be considered progressive disease in the absence of other clinical findings.

5.1 Hepatotoxicity

Fatal and/or serious hepatotoxicity occurred in 18% of patients treated with Zydelig monotherapy and 16% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies. Elevations in ALT or AST greater than 5 times the upper limit of normal have occurred [see Adverse Reactions (6.1)]. These findings were generally observed within the first 12 weeks of treatment and were reversible with dose interruption. After resumption of treatment at a lower dose, 26% of patients had recurrence of ALT and AST elevations. Discontinue Zydelig for recurrent hepatotoxicity.

Avoid concurrent use of Zydelig with other drugs that may cause liver toxicity.

Monitor ALT and AST in all patients every 2 weeks for the first 3 months of treatment, every 4 weeks for the next 3 months, then every 1 to 3 months thereafter. Monitor weekly for liver toxicity if the ALT or AST rises above 3 times the upper limit of normal until resolved. Withhold Zydelig if the ALT or AST is greater than 5 times the upper limit of normal, and continue to monitor AST, ALT and total bilirubin weekly until the abnormality is resolved [see Dosage and Administration (2.2)].

5.2 Severe Diarrhea or Colitis

Severe diarrhea or colitis (Grade 3 or higher) occurred in 14% of patients treated with Zydelig monotherapy and 20% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies [see Adverse Reactions (6.1)]. Diarrhea can occur at any time. Avoid concurrent use of Zydelig and other drugs that cause diarrhea. Diarrhea due to Zydelig responds poorly to antimotility agents. Median time to resolution ranged between 1 week and 1 month across trials, following interruption of Zydelig therapy and in some instances, use of corticosteroids [see Dosage and Administration (2.2)].

5.3 Pneumonitis

Fatal and serious pneumonitis occurred in patients treated with Zydelig. Clinical manifestations included interstitial infiltrates and organizing pneumonia. In randomized clinical trials of combination therapies, pneumonitis occurred in 4% of patients treated with Zydelig compared to 1% on the comparator arms. Time to onset of pneumonitis ranged from <1 to 15 months. Monitor patients on Zydelig for pulmonary symptoms. In patients taking Zydelig who present with pulmonary symptoms such as cough, dyspnea, hypoxia, interstitial infiltrates on a radiologic exam, or a decline by more than 5% in oxygen saturation, interrupt Zydelig until the etiology has been determined. If symptomatic pneumonitis or organizing pneumonia is diagnosed, initiate appropriate treatment with corticosteroids and permanently discontinue Zydelig [see Dosage and Administration (2.2)].

5.4 Infections

Fatal and/or serious infections occurred in 21% of patients treated with Zydelig monotherapy and 48% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies [see Adverse Reactions (6.1)]. The most common infections were pneumonia, sepsis, and febrile neutropenia. Treat infections prior to initiation of Zydelig therapy. Monitor patients on Zydelig for signs and symptoms of infection, and interrupt Zydelig for Grade 3 or higher infection [see Dosage and Administration (2.2)].

Serious or fatal Pneumocystis jirovecii pneumonia (PJP) or cytomegalovirus (CMV) occurred in <1% of patients treated with Zydelig. Provide PJP prophylaxis during treatment with Zydelig. Interrupt Zydelig in patients with suspected PJP infection of any grade, and permanently discontinue Zydelig if PJP infection of any grade is confirmed. Regular clinical and laboratory monitoring for CMV infection is recommended in patients with history of CMV infection or positive CMV serology at the start of treatment with Zydelig. Interrupt Zydelig in the setting of positive CMV PCR or antigen test until the viremia has resolved. If Zydelig is subsequently resumed, patients should be monitored by PCR or antigen test for CMV reactivation at least monthly [see Dosage and Administration (2.2)].

5.5 Intestinal Perforation

Fatal and serious intestinal perforation occurred in Zydelig-treated patients. At the time of perforation, some patients had moderate to severe diarrhea. Advise patients to promptly report any new or worsening abdominal pain, chills, fever, nausea, or vomiting. Discontinue Zydelig permanently in patients who experience intestinal perforation.

5.6 Severe Cutaneous Reactions

Fatal cases of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have occurred in patients treated with Zydelig. If SJS or TEN is suspected, interrupt Zydelig until the etiology of the reaction has been determined. If SJS or TEN is confirmed, permanently discontinue Zydelig.

Other severe or life-threatening (Grade ≥3) cutaneous reactions, including dermatitis exfoliative, rash, rash erythematous, rash generalized, rash macular, rash maculo-papular, rash papular, rash pruritic, exfoliative rash, and skin disorder, have been reported in Zydelig-treated patients. Monitor patients for the development of severe cutaneous reactions and discontinue Zydelig.

5.7 Anaphylaxis

Serious allergic reactions, including anaphylaxis, have been reported in patients on Zydelig. In patients who develop serious allergic reactions, discontinue Zydelig permanently and institute appropriate supportive measures.

5.8 Neutropenia

Treatment-emergent Grade 3 or 4 neutropenia occurred in 25% of patients treated with Zydelig monotherapy and 58% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies. Monitor blood counts at least every 2 weeks for the first 6 months of therapy, and at least weekly in patients while neutrophil counts are less than 1.0 Gi/L [see Dosage and Administration (2.2)].

5.9 Embryo-fetal Toxicity

Based on findings in animals and its mechanism of action, Zydelig may cause fetal harm when administered to a pregnant woman. In animal reproduction studies, administration of idelalisib to pregnant rats during organogenesis caused decreased fetal weight and congenital malformations at systemic exposures 12 times those reported in patients at the recommended dose of 150 mg twice daily. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 1 month after the last dose. [see Use in Specific Populations (8.1, 8.3), Clinical Pharmacology (12.1), and Nonclinical Toxicology (13.1)].

6.1 Clinical Trial Experience

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.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Zydelig. Because postmarketing 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.

Skin and Subcutaneous Disorders - Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN)

7.1 Effects of Other Drugs on Zydelig

Table 6 lists the potential effects of the coadministration of strong CYP3A modulators on Zydelig.

7.2 Effects of Zydelig on Other Drugs

The coadministration of Zydelig with a CYP3A substrate may increase the concentrations of this CYP3A substrate. Avoid coadministration of Zydelig with sensitive CYP3A substrates [see Clinical Pharmacology (12.3)].

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

8.4 Pediatric Use

Safety and effectiveness of Zydelig in children less than 18 years of age have not been established.

8.5 Geriatric Use

In clinical trials of Zydelig in 615 patients with FL, SLL, and CLL, 327 (53%) patients were age 65 and older. No major differences in effectiveness were observed. When comparing patients 65 years of age or older to younger patients with indolent non-Hodgkin lymphoma, older patients had a higher incidence of discontinuation due to an adverse reaction (28% vs 20%), higher incidence of serious adverse reactions (64% vs 37%), and higher incidence of death (11% vs 5%). When comparing patients 65 years of age or older to younger patients with CLL, older patients had a higher incidence of discontinuation due to an adverse reaction (36% vs 28%), higher incidence of serious adverse reactions (73% vs 67%), and higher incidence of death (13% vs 9%).

8.6 Hepatic Impairment

Dose adjustment is not recommended for patients with ALT or AST or bilirubin > upper limit of normal (ULN); however, limited safety and efficacy data are available for patients with baseline AST or ALT > 2.5 × ULN or bilirubin > 1.5 × ULN. Monitor patients with baseline hepatic impairment for signs of Zydelig toxicity [see Warnings and Precautions (5)]. Follow dose modifications for adverse reactions [see Dosage and Administration (2.2)].

12.1 Mechanism of Action

Idelalisib is an inhibitor of PI3Kδ kinase, which is expressed in normal and malignant B-cells. Idelalisib induced apoptosis and inhibited proliferation in cell lines derived from malignant B-cells and in primary tumor cells. Idelalisib inhibits several cell signaling pathways, including B-cell receptor (BCR) signaling and the CXCR4 and CXCR5 signaling, which are involved in trafficking and homing of B-cells to the lymph nodes and bone marrow. Treatment of lymphoma cells with idelalisib resulted in inhibition of chemotaxis and adhesion, and reduced cell viability.

12.2 Pharmacodynamics

12.3 Pharmacokinetics

Idelalisib exposure increased in a less than dose-proportional manner over a dose range of 50 mg to 350 mg twice daily (0.3 to 2.3 times the approved recommended dosage).

Following 150 mg twice daily administration of idelalisib, average (% coefficient of variation) maximum concentrations (Cmax) and area under the curve (AUC) at steady-state were 1861 (43%) ng/mL and 10598 (41%) ng∙h/mL for idelalisib.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Idelalisib was not carcinogenic in a 26-week study in transgenic mice when administered daily by oral gavage at doses up to 500 mg/kg/day in males and 1000 mg/kg/day in females. Idelalisib was not carcinogenic in a 2-year study in rats when administered daily by oral gavage at exposures 0.40/0.62-fold (male/female), compared to the exposure in patients with hematologic malignancies administered the recommended dose of 150 mg twice daily.

Idelalisib did not induce mutations in the bacterial mutagenesis (Ames) assay and was not clastogenic in the in vitro chromosome aberration assay using human peripheral blood lymphocytes. Idelalisib was genotoxic in males in the in vivo rat micronucleus study at a high dose of 2000 mg/kg.

Idelalisib may impair fertility in humans. In a fertility study, treated male rats (25, 50, or 100 mg/kg/day of idelalisib) were mated with untreated females. Decreased epididymidal and testicular weights were observed at all dose levels and reduced sperm concentration at the mid- and high doses; however, there were no adverse effects on fertility parameters. The low dose in males resulted in an exposure (AUC) that is approximately 50% of the exposure in patients at the recommended dose of 150 mg twice daily.

In a separate fertility study, treated female rats (25, 50, or 100 mg/kg/day of idelalisib) were mated with untreated males. There were no adverse effects on fertility parameters; however, there was a decrease in the number of live embryos at the high dose. The high dose in females resulted in an exposure (AUC) that is approximately 17-fold the exposure in patients at the recommended dose of 150 mg twice daily.

13.2 Animal Toxicology and/or Pharmacology

Toxicities observed in animals and not reported in patients include cardiac toxicity (cardiomyopathy, inflammation, and increased heart weight) and pancreatic findings (inflammation, hemorrhage, and low-incidence acinar degeneration and hyperplasia). These findings were observed in Sprague-Dawley rats in toxicology studies at exposures (AUCs) higher than those reported in patients at the recommended dose of 150 mg twice daily. Cardiac inflammation was mainly seen in a 28-day study in rats, the other findings were observed in the 13-week and/or 6-month studies.

14.1 Relapsed Chronic Lymphocytic Leukemia

14.2 Relapsed Follicular B-cell non-Hodgkin Lymphoma

14.3 Relapsed Small Lymphocytic Lymphoma

Store between 20–30 °C (68–86 °F) with excursions permitted 15–30 °C (59–86 °F).

• Dispense only in original container.
• Do not use if seal over bottle opening is broken or missing.

• Hepatotoxicity

Advise patients that Zydelig can cause significant elevations in liver enzymes, and that serial testing of serum liver tests (ALT, AST, and bilirubin) are recommended while taking Zydelig [see Warnings and Precautions (5.1)]. Advise patients to report symptoms of liver dysfunction including jaundice, bruising, abdominal pain, or bleeding.

• Severe Diarrhea or Colitis

Advise patients that Zydelig may cause severe diarrhea or colitis and to notify their healthcare provider immediately if the number of bowel movements in a day increases by six or more [see Warnings and Precautions (5.2)].

• Pneumonitis

Advise patients of the possibility of pneumonitis, and to report any new or worsening respiratory symptoms including cough or dyspnea [see Warnings and Precautions (5.3)].

• Infections

Advise patients that Zydelig can cause serious infections that may be fatal. Advise patients to immediately report symptoms of infection (e.g. pyrexia) [see Warnings and Precautions (5.4)].

• Intestinal Perforation

Advise patients of the possibility for intestinal perforation and to notify their healthcare provider immediately if they experience severe abdominal pain [see Warnings and Precautions (5.5)].

• Severe Cutaneous Reactions

Advise patients that Zydelig may cause severe cutaneous reactions and to notify their healthcare provider immediately if they develop a severe skin reaction [see Warnings and Precautions (5.6)].

• Anaphylaxis

Advise patients that anaphylaxis can occur during treatment with Zydelig and to notify their healthcare provider immediately if they experience symptoms of anaphylaxis [see Warnings and Precautions (5.7)].

• Neutropenia

Advise patients of the need for periodic monitoring of blood counts. Advise patients to notify their healthcare provider immediately if they develop a fever or any signs of infection [see Warnings and Precautions (5.8)].

• Embryo-Fetal Toxicity

Advise females to inform their healthcare provider if they are pregnant or become pregnant. Inform female patients of the risk to a fetus and potential loss of the pregnancy [see Use in Specific Populations (8.1)].

Advise females of reproductive potential to use effective contraception during treatment and for 1 month after receiving the last dose of Zydelig [see Warnings and Precautions (5.9) and Use in Specific Populations (8.1, 8.3)].

Advise lactating women not to breastfeed during treatment with Zydelig and for at least 1 month after the last dose [see Use in Specific Populations (8.2)].

• Instructions for Taking Zydelig

Advise patients to take Zydelig exactly as prescribed and not to change their dose or to stop taking Zydelig unless they are told to do so by their healthcare provider. Zydelig may be taken with or without food. Zydelig tablets should be swallowed whole. Advise patients that if a dose of Zydelig is missed by less than 6 hours, to take the missed dose right away and take the next dose as usual. If a dose of Zydelig is missed by more than 6 hours, advise patients to wait and take the next dose at the usual time.