These Highlights Do Not Include All The Information Needed To Use Zydelig Safely And Effectively. See Full Prescribing Information For Zydelig.

Limitations of Use

Zydelig is not indicated and is not recommended for first-line treatment of any patient, including patients with CLL, small lymphocytic lymphoma (SLL), follicular lymphoma (FL), and other indolent non-Hodgkin lymphomas.

Zydelig is not indicated and is not recommended in combination with bendamustine and rituximab, or in combination with rituximab for the treatment of patients with FL, SLL, and other indolent non-Hodgkin lymphomas.

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.

Idelalisib is a kinase inhibitor. The chemical name for idelalisib is 5-fluoro-3-phenyl-2-[(1S)-1-(9H-purin-6-ylamino)propyl]quinazolin-4(3H)-one. It has a molecular formula of C22H18FN7O and a molecular weight of 415.42 g/mol. Idelalisib has the following structural formula:

Idelalisib is a white to off-white solid with a pH-dependent aqueous solubility ranging from <0.1 mg/mL at pH 5–7 to over 1 mg/mL at pH 2 under ambient conditions.

Zydelig (idelalisib) tablets are for oral use. Each tablet contains either 100 mg or 150 mg of idelalisib with the following inactive ingredients: microcrystalline cellulose, hydroxypropyl cellulose, croscarmellose sodium, sodium starch glycolate, magnesium stearate and a tablet coating. The tablet coating consists of polyethylene glycol, talc, polyvinyl alcohol, and titanium dioxide and of FD&C Yellow #6/Sunset Yellow FCF Aluminum Lake (for the 100 mg tablet) and red iron oxide (for the 150 mg tablet).

Fatal and/or serious infections occurred in 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)].

Fatal and serious pneumonitis occurred in patients treated with Zydelig [see Adverse Reactions (6.1)]. 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)].

Grade 3 or 4 neutropenia occurred in 58% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies [see Adverse Reactions (6.1)]. 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. Interrupt Zydelig until resolution and resume at reduced dose [see Dosage and Administration (2.2)].

Safety and effectiveness of Zydelig in pediatric patients have not been established.

Of the 490 patients with relapsed CLL who were treated with Zydelig in combination trials, 271 (55%) were 65 years of age and older. 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%).

Fatal and/or serious hepatotoxicity occurred in 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)].

Zydelig was evaluated in a randomized, double-blind, placebo-controlled study GS-US-312-0116 (referred to as 312-0116) (NCT01539512) in 220 patients with relapsed CLL who required treatment and were unable to tolerate standard chemoimmunotherapy due to coexisting medical conditions, reduced renal function as measured by creatinine clearance < 60 mL/min, or NCI CTCAE Grade ≥ 3 neutropenia or Grade ≥ 3 thrombocytopenia resulting from myelotoxic effects of prior therapy with cytotoxic agents. Patients were randomized 1:1 to receive 8 doses of rituximab (first dose at 375 mg/m², subsequent doses at 500 mg/m² every 2 weeks for 4 infusions and every 4 weeks for an additional 4 infusions) in combination with either an placebo taken orally twice daily or with Zydelig 150 mg taken orally twice daily until disease progression or unacceptable toxicity.

The median age was 71 years (range 47, 92) with 78% over 65, 66% were male, and 90% were White. The median time since diagnosis was 8.5 years. The median number of prior therapies was 3. Nearly all (96%) patients had received prior anti-CD20 monoclonal antibodies. The most common (>15%) prior regimens were: bendamustine + rituximab (BR) (98 patients, 45%), fludarabine + cyclophosphamide + rituximab (75 patients, 34%), single-agent rituximab (67 patients, 31%), fludarabine + rituximab (37 patients, 17%), and chlorambucil (36 patients, 16%). The median CIRS (Cumulative Illness Rating Scale) score was 8 (range 0–17), and 85% of patients had a score of >6. Median Karnofsky score was 80. Median estimated Creatinine Clearance (eCLcr) was 63.6 mL/min, with 41% of patients having an eCLcr of <60 mL/min. At screening, 19.5% of patients had a platelet count of <50 × 10⁹/L, and 13.2% had an absolute neutrophil count (ANC) of <1 × 10⁹/L.

The efficacy of Zydelig was based on progression free survival (PFS), as assessed by an independent review committee (IRC). The trial was stopped for efficacy following the first pre-specified interim analysis. Results of a second interim analysis continued to show a statistically significant improvement for Zydelig + R compared to placebo + R for the major efficacy outcome measure of PFS (HR: 0.18, 95% CI [0.10, 0.32], p <0.0001).

At the final analysis, with a median follow-up of 8.3 months for the Zydelig + R group, and 5.6 months for the placebo + R group, the median PFS for the Zydelig + R group was 19.4 months (95% CI: 12.3, Not Reached) versus 6.5 months (95% CI: 4.0, 7.3) for the placebo + R group (HR: 0.15, 95% CI [0.09, 0.24], p < 0.0001).

Updated efficacy results are shown in Table 7 and the Kaplan-Meier curve for PFS is shown in Figure 1.

Figure 1 Kaplan-Meier Plot of IRC-Assessed PFS for Study 312-0116

Zydelig is contraindicated in patients with a history of serious hypersensitivity reactions to idelalisib, including anaphylaxis, or patients with a history of toxic epidermal necrolysis with any drug [see Warnings and Precautions (5.6, 5.7)] .

The following clinically significant adverse reactions are described elsewhere in the labeling.

• Hepatotoxicity [see Warnings and Precautions (5.1)]
• Severe Diarrhea or Colitis [see Warnings and Precautions (5.2)]
• Pneumonitis [see Warnings and Precautions (5.3)]
• Infections [see Warnings and Precautions (5.4)]
• Intestinal Perforation [see Warnings and Precautions (5.5)]
• Severe Cutaneous Reactions [see Warnings and Precautions (5.6)]
• Hypersensitivity Reactions [see Warnings and Precautions (5.7)]
• Neutropenia [see Warnings and Precautions (5.8)]

• Strong CYP3A Inhibitors: Additional monitoring required if alternative therapy is not available. (7.1)
• Strong CYP3A Inducers: Avoid coadministration of strong CYP3A inducers. (7.1)
• CYP3A Substrates: Avoid coadministration of sensitive CYP3A substrates. (7.2)

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 (C_max) and area under the curve (AUC) at steady-state were 1861 (43%) ng/mL and 10598 (41%) ng∙h/mL for idelalisib.

The recommended dosage of Zydelig is 150 mg administered orally twice daily with or without food until disease progression or unacceptable toxicity. The optimal and safe dosing regimen for patients who receive treatment longer than several months is unknown.

Swallow tablets whole.

If a planned dose of Zydelig is missed by less than 6 hours, take the missed dose as soon as possible and take the next dose as usual. If a dose of Zydelig is missed by more than 6 hours, skip the missed dose and take the next dose at the usual time.

No dose adjustment is 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 adverse reactions [see Warnings and Precautions (5)]. Follow dosage modifications for adverse reactions [see Dosage and Administration (2.2)].

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.

Idelalisib is an inhibitor of phosphatidylinositol 3-kinase, PI3Kδ, 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.

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 with Zydelig and for 1 month after the last dose [see Use in Specific Populations (8.1, 8.3)].

• Severe Cutaneous Reactions: Monitor patients for the development of severe cutaneous reactions. Permanently discontinue Zydelig if confirmed. (2.2, 5.6)
• Hypersensitivity Reactions: Permanently discontinue Zydelig and institute appropriate supportive measures. (2.2, 5.7)
• Neutropenia: Monitor blood counts. Interrupt Zydelig until resolution and resume at reduced dose. (2.2, 5.8)
• Embryo-fetal Toxicity: May cause fetal harm. Advise females of reproductive potential of potential risk to a fetus and to use effective contraception. (5.9, 8.1, 8.3)

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.

Recommended dosage: 150 mg orally twice daily. (2.1)

Tablets:

• 100 mg: orange, oval-shaped, film-coated tablet debossed with "GSI" on one side and "100" on the other side.
• 150 mg: pink, oval-shaped, film-coated tablet debossed with "GSI" on one side and "150" on the other side.

The following adverse reactions have been identified during postapproval use of Zydelig. 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.

Skin and Subcutaneous Disorders - Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)

Lactation: Advise not to breastfeed. (8.2)

Severe diarrhea or colitis (Grade 3 or higher) occurred in 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)].

Fatal cases of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have occurred in patients treated with Zydelig. Cases of drug reaction with eosinophilia and systemic symptoms (DRESS) have also occurred [see Adverse Reactions (6.2)]. Zydelig is contraindicated in patients with a history of toxic epidermal necrolysis [see Contraindications (4)]. If SJS, TEN, or DRESS is suspected, interrupt Zydelig until the etiology of the reaction has been determined. If SJS, TEN, or DRESS is confirmed, permanently discontinue Zydelig [see Dosage and Administration (2.2)].

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 patients treated with Zydelig. Monitor patients for the development of other severe or life-threatening cutaneous reactions and permanently discontinue Zydelig [see Dosage and Administration (2.2)].

Serious hypersensitivity reactions, including anaphylaxis, have been reported in patients on Zydelig. Zydelig is contraindicated in patients with a history of serious hypersensitivity reactions to idelalisib, including anaphylaxis [see Contraindications (4)]. In patients who develop serious hypersensitivity reactions, permanently discontinue Zydelig [see Dosage and Administration (2.2)] and institute appropriate supportive measures.

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.

The pooled safety population described in the WARNINGS AND PRECAUTIONS reflect exposure to Zydelig at a dosage of 150 mg twice daily in 110 patients administered in combination with rituximab in Study 312-0116, and in combination with other drugs in 380 patients. Among 490 patients who received Zydelig, 74% were exposed for 6 months or longer and 50% were exposed for one year or longer. In this pooled safety population, the most common (> 30%) adverse reactions were diarrhea, pneumonia, pyrexia, fatigue, rash, cough, and nausea. Common laboratory abnormalities were neutropenia, ALT elevations and AST elevations.

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Zydelig tablets supplied as follows:

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

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)].

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.

Table 1 presents the dosage modification for specific adverse reactions.

For other severe or life-threatening adverse reactions, withhold Zydelig until resolution. If resuming Zydelig after interruption for other severe or life-threatening toxicities, reduce the dosage to 100 mg orally twice daily. Permanently discontinue Zydelig for recurrence of other severe or life-threatening Zydelig-related toxicity upon rechallenge.

No dosage modification is recommended 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.

Zydelig may cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)].

NDC 61958-1701-1

60 tablets

Zydelig^®

(idelalisib) Tablets

100 mg

DISPENSER: Each time Zydelig^® is dispensed

give the patient the attached Medication Guide.

NDC 61958-1702-1

60 tablets

Zydelig^®

(idelalisib) Tablets

150 mg

DISPENSER: Each time Zydelig^® is dispensed

give the patient the attached Medication Guide.

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.

Fatal and/or serious hepatotoxicity occurred in 16% of Zydelig-treated patients. Monitor hepatic function prior to and during treatment. Interrupt and then reduce or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.1)].

Fatal and/or serious and severe diarrhea or colitis occurred in 20% of Zydelig-treated patients. Monitor for the development of severe diarrhea or colitis. Interrupt and then reduce or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.2)].

Fatal and/or serious pneumonitis occurred in 4% of Zydelig-treated patients. Monitor for pulmonary symptoms and bilateral interstitial infiltrates. Interrupt or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.3)].

Fatal and/or serious infections occurred in 48% of Zydelig-treated patients. Monitor for signs and symptoms of infection. Interrupt Zydelig if infection is suspected [see Dosage and Administration (2.2), Warnings and Precautions (5.4)].

Fatal and serious intestinal perforation can occur in Zydelig-treated patients across clinical trials. Discontinue Zydelig for intestinal perforation [see Warnings and Precautions (5.5)].

Limitations of Use

Zydelig is not indicated and is not recommended for first-line treatment of any patient, including patients with CLL, small lymphocytic lymphoma (SLL), follicular lymphoma (FL), and other indolent non-Hodgkin lymphomas.

Zydelig is not indicated and is not recommended in combination with bendamustine and rituximab, or in combination with rituximab for the treatment of patients with FL, SLL, and other indolent non-Hodgkin lymphomas.

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.

Idelalisib is a kinase inhibitor. The chemical name for idelalisib is 5-fluoro-3-phenyl-2-[(1S)-1-(9H-purin-6-ylamino)propyl]quinazolin-4(3H)-one. It has a molecular formula of C22H18FN7O and a molecular weight of 415.42 g/mol. Idelalisib has the following structural formula:

Idelalisib is a white to off-white solid with a pH-dependent aqueous solubility ranging from <0.1 mg/mL at pH 5–7 to over 1 mg/mL at pH 2 under ambient conditions.

Zydelig (idelalisib) tablets are for oral use. Each tablet contains either 100 mg or 150 mg of idelalisib with the following inactive ingredients: microcrystalline cellulose, hydroxypropyl cellulose, croscarmellose sodium, sodium starch glycolate, magnesium stearate and a tablet coating. The tablet coating consists of polyethylene glycol, talc, polyvinyl alcohol, and titanium dioxide and of FD&C Yellow #6/Sunset Yellow FCF Aluminum Lake (for the 100 mg tablet) and red iron oxide (for the 150 mg tablet).

Fatal and/or serious infections occurred in 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)].

Fatal and serious pneumonitis occurred in patients treated with Zydelig [see Adverse Reactions (6.1)]. 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)].

Grade 3 or 4 neutropenia occurred in 58% of patients treated with Zydelig in combination with rituximab or with unapproved combination therapies [see Adverse Reactions (6.1)]. 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. Interrupt Zydelig until resolution and resume at reduced dose [see Dosage and Administration (2.2)].

Safety and effectiveness of Zydelig in pediatric patients have not been established.

Of the 490 patients with relapsed CLL who were treated with Zydelig in combination trials, 271 (55%) were 65 years of age and older. 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%).

Fatal and/or serious hepatotoxicity occurred in 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)].

Zydelig was evaluated in a randomized, double-blind, placebo-controlled study GS-US-312-0116 (referred to as 312-0116) (NCT01539512) in 220 patients with relapsed CLL who required treatment and were unable to tolerate standard chemoimmunotherapy due to coexisting medical conditions, reduced renal function as measured by creatinine clearance < 60 mL/min, or NCI CTCAE Grade ≥ 3 neutropenia or Grade ≥ 3 thrombocytopenia resulting from myelotoxic effects of prior therapy with cytotoxic agents. Patients were randomized 1:1 to receive 8 doses of rituximab (first dose at 375 mg/m², subsequent doses at 500 mg/m² every 2 weeks for 4 infusions and every 4 weeks for an additional 4 infusions) in combination with either an placebo taken orally twice daily or with Zydelig 150 mg taken orally twice daily until disease progression or unacceptable toxicity.

The median age was 71 years (range 47, 92) with 78% over 65, 66% were male, and 90% were White. The median time since diagnosis was 8.5 years. The median number of prior therapies was 3. Nearly all (96%) patients had received prior anti-CD20 monoclonal antibodies. The most common (>15%) prior regimens were: bendamustine + rituximab (BR) (98 patients, 45%), fludarabine + cyclophosphamide + rituximab (75 patients, 34%), single-agent rituximab (67 patients, 31%), fludarabine + rituximab (37 patients, 17%), and chlorambucil (36 patients, 16%). The median CIRS (Cumulative Illness Rating Scale) score was 8 (range 0–17), and 85% of patients had a score of >6. Median Karnofsky score was 80. Median estimated Creatinine Clearance (eCLcr) was 63.6 mL/min, with 41% of patients having an eCLcr of <60 mL/min. At screening, 19.5% of patients had a platelet count of <50 × 10⁹/L, and 13.2% had an absolute neutrophil count (ANC) of <1 × 10⁹/L.

The efficacy of Zydelig was based on progression free survival (PFS), as assessed by an independent review committee (IRC). The trial was stopped for efficacy following the first pre-specified interim analysis. Results of a second interim analysis continued to show a statistically significant improvement for Zydelig + R compared to placebo + R for the major efficacy outcome measure of PFS (HR: 0.18, 95% CI [0.10, 0.32], p <0.0001).

At the final analysis, with a median follow-up of 8.3 months for the Zydelig + R group, and 5.6 months for the placebo + R group, the median PFS for the Zydelig + R group was 19.4 months (95% CI: 12.3, Not Reached) versus 6.5 months (95% CI: 4.0, 7.3) for the placebo + R group (HR: 0.15, 95% CI [0.09, 0.24], p < 0.0001).

Updated efficacy results are shown in Table 7 and the Kaplan-Meier curve for PFS is shown in Figure 1.

Figure 1 Kaplan-Meier Plot of IRC-Assessed PFS for Study 312-0116

Zydelig is contraindicated in patients with a history of serious hypersensitivity reactions to idelalisib, including anaphylaxis, or patients with a history of toxic epidermal necrolysis with any drug [see Warnings and Precautions (5.6, 5.7)] .

The following clinically significant adverse reactions are described elsewhere in the labeling.

• Hepatotoxicity [see Warnings and Precautions (5.1)]
• Severe Diarrhea or Colitis [see Warnings and Precautions (5.2)]
• Pneumonitis [see Warnings and Precautions (5.3)]
• Infections [see Warnings and Precautions (5.4)]
• Intestinal Perforation [see Warnings and Precautions (5.5)]
• Severe Cutaneous Reactions [see Warnings and Precautions (5.6)]
• Hypersensitivity Reactions [see Warnings and Precautions (5.7)]
• Neutropenia [see Warnings and Precautions (5.8)]

• Strong CYP3A Inhibitors: Additional monitoring required if alternative therapy is not available. (7.1)
• Strong CYP3A Inducers: Avoid coadministration of strong CYP3A inducers. (7.1)
• CYP3A Substrates: Avoid coadministration of sensitive CYP3A substrates. (7.2)

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 (C_max) and area under the curve (AUC) at steady-state were 1861 (43%) ng/mL and 10598 (41%) ng∙h/mL for idelalisib.

The recommended dosage of Zydelig is 150 mg administered orally twice daily with or without food until disease progression or unacceptable toxicity. The optimal and safe dosing regimen for patients who receive treatment longer than several months is unknown.

Swallow tablets whole.

If a planned dose of Zydelig is missed by less than 6 hours, take the missed dose as soon as possible and take the next dose as usual. If a dose of Zydelig is missed by more than 6 hours, skip the missed dose and take the next dose at the usual time.

No dose adjustment is 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 adverse reactions [see Warnings and Precautions (5)]. Follow dosage modifications for adverse reactions [see Dosage and Administration (2.2)].

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.

Idelalisib is an inhibitor of phosphatidylinositol 3-kinase, PI3Kδ, 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.

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 with Zydelig and for 1 month after the last dose [see Use in Specific Populations (8.1, 8.3)].

• Severe Cutaneous Reactions: Monitor patients for the development of severe cutaneous reactions. Permanently discontinue Zydelig if confirmed. (2.2, 5.6)
• Hypersensitivity Reactions: Permanently discontinue Zydelig and institute appropriate supportive measures. (2.2, 5.7)
• Neutropenia: Monitor blood counts. Interrupt Zydelig until resolution and resume at reduced dose. (2.2, 5.8)
• Embryo-fetal Toxicity: May cause fetal harm. Advise females of reproductive potential of potential risk to a fetus and to use effective contraception. (5.9, 8.1, 8.3)

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.

Recommended dosage: 150 mg orally twice daily. (2.1)

Tablets:

• 100 mg: orange, oval-shaped, film-coated tablet debossed with "GSI" on one side and "100" on the other side.
• 150 mg: pink, oval-shaped, film-coated tablet debossed with "GSI" on one side and "150" on the other side.

The following adverse reactions have been identified during postapproval use of Zydelig. 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.

Skin and Subcutaneous Disorders - Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)

Lactation: Advise not to breastfeed. (8.2)

Severe diarrhea or colitis (Grade 3 or higher) occurred in 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)].

Fatal cases of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have occurred in patients treated with Zydelig. Cases of drug reaction with eosinophilia and systemic symptoms (DRESS) have also occurred [see Adverse Reactions (6.2)]. Zydelig is contraindicated in patients with a history of toxic epidermal necrolysis [see Contraindications (4)]. If SJS, TEN, or DRESS is suspected, interrupt Zydelig until the etiology of the reaction has been determined. If SJS, TEN, or DRESS is confirmed, permanently discontinue Zydelig [see Dosage and Administration (2.2)].

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 patients treated with Zydelig. Monitor patients for the development of other severe or life-threatening cutaneous reactions and permanently discontinue Zydelig [see Dosage and Administration (2.2)].

Serious hypersensitivity reactions, including anaphylaxis, have been reported in patients on Zydelig. Zydelig is contraindicated in patients with a history of serious hypersensitivity reactions to idelalisib, including anaphylaxis [see Contraindications (4)]. In patients who develop serious hypersensitivity reactions, permanently discontinue Zydelig [see Dosage and Administration (2.2)] and institute appropriate supportive measures.

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.

The pooled safety population described in the WARNINGS AND PRECAUTIONS reflect exposure to Zydelig at a dosage of 150 mg twice daily in 110 patients administered in combination with rituximab in Study 312-0116, and in combination with other drugs in 380 patients. Among 490 patients who received Zydelig, 74% were exposed for 6 months or longer and 50% were exposed for one year or longer. In this pooled safety population, the most common (> 30%) adverse reactions were diarrhea, pneumonia, pyrexia, fatigue, rash, cough, and nausea. Common laboratory abnormalities were neutropenia, ALT elevations and AST elevations.

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Zydelig tablets supplied as follows:

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

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)].

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.

Table 1 presents the dosage modification for specific adverse reactions.

For other severe or life-threatening adverse reactions, withhold Zydelig until resolution. If resuming Zydelig after interruption for other severe or life-threatening toxicities, reduce the dosage to 100 mg orally twice daily. Permanently discontinue Zydelig for recurrence of other severe or life-threatening Zydelig-related toxicity upon rechallenge.

No dosage modification is recommended 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.

Zydelig may cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)].

NDC 61958-1701-1

60 tablets

Zydelig^®

(idelalisib) Tablets

100 mg

DISPENSER: Each time Zydelig^® is dispensed

give the patient the attached Medication Guide.

NDC 61958-1702-1

60 tablets

Zydelig^®

(idelalisib) Tablets

150 mg

DISPENSER: Each time Zydelig^® is dispensed

give the patient the attached Medication Guide.

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.

Fatal and/or serious hepatotoxicity occurred in 16% of Zydelig-treated patients. Monitor hepatic function prior to and during treatment. Interrupt and then reduce or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.1)].

Fatal and/or serious and severe diarrhea or colitis occurred in 20% of Zydelig-treated patients. Monitor for the development of severe diarrhea or colitis. Interrupt and then reduce or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.2)].

Fatal and/or serious pneumonitis occurred in 4% of Zydelig-treated patients. Monitor for pulmonary symptoms and bilateral interstitial infiltrates. Interrupt or discontinue Zydelig as recommended [see Dosage and Administration (2.2), Warnings and Precautions (5.3)].

Fatal and/or serious infections occurred in 48% of Zydelig-treated patients. Monitor for signs and symptoms of infection. Interrupt Zydelig if infection is suspected [see Dosage and Administration (2.2), Warnings and Precautions (5.4)].

Fatal and serious intestinal perforation can occur in Zydelig-treated patients across clinical trials. Discontinue Zydelig for intestinal perforation [see Warnings and Precautions (5.5)].