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Zydelig

Last reviewed on RxList: 10/22/2018
Drug Description

ZYDELIG®
(idelalisib) tablets, for oral use

WARNING

FATAL AND SERIOUS TOXICITIES: HEPATIC, SEVERE DIARRHEA, COLITIS, PNEUMONITIS, INFECTIONS, and INTESTINAL PERFORATION

Fatal and/or serious hepatotoxicity occurred in 16% to 18% 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, WARNINGS AND PRECAUTIONS].

Fatal and/or serious and severe diarrhea or colitis occurred in 14% to 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, WARNINGS AND PRECAUTIONS].

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, WARNINGS AND PRECAUTIONS].

Fatal and/or serious infections occurred in 21% to 48% of Zydelig-treated patients. Monitor for signs and symptoms of infection. Interrupt Zydelig if infection is suspected [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].

Fatal and serious intestinal perforation can occur in Zydelig-treated patients across clinical trials. Discontinue Zydelig for intestinal perforation [see WARNINGS AND PRECAUTIONS].

DESCRIPTION

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

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:

ZYDELIG® (idelalisib) Structural Formula Illustration

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 administration. 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).

Indications

INDICATIONS

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.

Limitation Of Use

Zydelig is not indicated and is not recommended for first line treatment of patients with CLL.

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]. 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.

Limitation Of Use

Zydelig is not indicated and is not recommended for first line treatment of patients with FL.

Zydelig is not indicated and is not recommended in combination with bendamustine and/or rituximab for the treatment of FL.

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]. 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.

Limitation Of Use

Zydelig is not indicated and is not recommended for first line treatment of patients with SLL.

Dosage

DOSAGE AND ADMINISTRATION

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.

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.

Table 1 Dose Modifications for Toxicities Due to Zydelig

Pneumonitis Any symptomatic pneumonitis
  Discontinue Zydelig in patients with any severity of symptomatic pneumonitis
ALT/AST >3-5 × ULN >5-20 × ULN >20 × ULN
  Maintain Zydelig dose. Monitor at least weekly until ≤1 x ULN. Withhold Zydelig.

Monitor at least weekly until ALT/AST are ≤1 x ULN, then may resume Zydelig at 100 mg BID.

Discontinue Zydelig permanently.
Bilirubin >1.5-3 × ULN >3-10 × ULN >10 × ULN
  Maintain Zydelig dose. Monitor at least weekly until ≤1 x ULN. Withhold Zydelig. Monitor at least weekly until bilirubin is ≤1 x ULN, then may resume Zydelig at 100 mg BID. Discontinue Zydelig permanently.
Diarrhea* Moderate diarrhea Severe diarrhea or hospitalization Life-threatening diarrhea
  Maintain Zydelig dose. Monitor at least weekly until resolved. Withhold Zydelig. Monitor at least weekly until resolved, then may resume Zydelig at 100 mg BID. Discontinue Zydelig permanently.
Neutropenia ANC 1.0 to <1.5 Gi/L ANC 0.5 to <1.0 Gi/L ANC <0.5 Gi/L
  Maintain Zydelig dose. Maintain Zydelig dose. Monitor ANC at least weekly. Interrupt Zydelig. Monitor ANC at least weekly until ANC ≥0.5 Gi/L, then may resume Zydelig at 100 mg BID.
Thrombocytopenia Platelets 50 to <75 Gi/L Platelets 25 to <50 Gi/L Platelets <25 Gi/L
  Maintain Zydelig dose. Maintain Zydelig dose. Monitor platelet counts at least weekly. Interrupt Zydelig. Monitor platelet count at least weekly. May resume Zydelig at 100 mg BID when platelets ≥25 Gi/L.
Infections Grade 3 or higher sepsis or pneumonia
  Interrupt Zydelig until infection has resolved.
  Evidence of CMV infection or viremia
  Interrupt Zydelig in patients with evidence of active CMV infection of any grade or viremia (positive PCR or antigen test) until the viremia has resolved. If Zydelig is resumed, monitor patients by PCR or antigen test for CMV reactivation at least monthly.
  Evidence of PJP infection
  Interrupt Zydelig in patients with suspected PJP infection of any grade. Permanently discontinue Zydelig if PJP infection is confirmed.
Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; BID, twice daily; ULN, upper limit of normal; CMV, cytomegalovirus; PCR: polymerase chain reaction; PJP: Pneumocystis jirovecii pneumonia
*Moderate diarrhea: increase of 4–6 stools per day over baseline; severe diarrhea: increase of ≥7 stools per day over baseline.

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.

HOW SUPPLIED

Dosage Forms And Strengths

150 mg tablets: pink, oval-shaped, film-coated tablet debossed with “GSI” on one side and “150” on the other side.

100 mg tablets: orange, oval-shaped, film-coated tablet debossed with “GSI” on one side and “100” on the other side.

Storage And Handling

Zydelig tablets supplied as follows:

Tablet Strength Package Configuration NDC No. Description of Tablet; Debossed on Tablet
150 mg High density polyethylene (HDPE) bottle with a polyester fiber coil, capped with a child-resistant closure. Each bottle contains 60 film-coated tablets. 61958-1702-1 Oval shaped; pink; “150” on one side and "GSI" on the other side
100 mg 61958-1701-1 Oval-shaped; orange; “100” on one side and “GSI” on the other side

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.

Manufactured by: Gilead Sciences, Inc. Foster City, CA 94404. Revised: Jan 2018.

Side Effects

SIDE EFFECTS

The following serious adverse reactions have been associated with Zydelig in clinical trials and are discussed in greater detail in other sections of the prescribing information.

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.

Summary Of Clinical Trials In Chronic Lymphocytic Leukemia

The safety data reflect exposure to Zydelig from two randomized, double-blind clinical trials (Studies 312-0116 and 312-0115) in 634 patients with relapsed CLL [see Clinical Studies] and one randomized, open-label trial in 259 patients with relapsed CLL (Study 312-0119).

Zydelig with Rituximab (Study 312-0116; NCT01539512)

Patients with relapsed CLL received up to 8 doses of rituximab (R) with or without Zydelig 150 mg twice daily. The median duration of exposure to Zydelig was 8 months.

Serious adverse reactions were reported in 65 (59%) patients treated with Zydelig + R The most frequent serious adverse reactions reported for patients treated with Zydelig + R were pneumonia (23%), diarrhea (10%), pyrexia (9%), sepsis (8%), and febrile neutropenia (5%). Adverse reactions that led to discontinuation of Zydelig occurred in 19 (17%) patients. The most common adverse reactions that led to treatment discontinuations were hepatotoxicity and diarrhea/colitis.

Forty-two (38%) patients had dose interruptions and sixteen (15%) patients had dose reductions due to adverse reactions or laboratory abnormalities. The most common reasons for dose interruptions or reductions were pneumonia, diarrhea or colitis, rash, and elevated transaminases.

Table 2 and Table 3 summarize common adverse reactions and laboratory abnormalities reported for Zydelig + R and placebo + R arms.

Table 2. Adverse Reactions Reported in ≥5% of Patients with CLL and Occurred at ≥2% Higher Incidence in Patients Receiving Zydelig in Study 312-0116

  Zydelig + R
N=110 (%)
Placebo + R
N=108 (%)
Adverse Reaction Any Grade Grade ≥3 Any Grade Grade ≥3
General disorders and administration site conditions
  pyrexia 44 (40) 3 (3) 20 (19) 1 (1)
  chills 27 (25) 2 (2) 17 (16) 0
  pain 8 (7) 0 1 (1) 0
Gastrointestinal disorders
  diarrhea (a) 35 (32) 12 (11) 20 (19) 0
  nausea 30 (27) 1 (1) 25 (23) 0
  abdominal pain(b) 20 (18) 1 (1) 17 (16) 2 (2)
  vomiting 17 (15) 0 9 (8) 0
  gastroesophageal reflux disease 11 (10) 1 (1) 0 0
  stomatitis 7 (6) 2 (2) 1 (1) 0
Respiratory, thoracic, and mediastinal disorders
  pneumonia (c) 33 (30) 23 (21) 20 (19) 14 (13)
Skin and subcutaneous tissue disorders
  rash (d) 27 (25) 4 (4) 7 (6) 1 (1)
Metabolism and Nutrition Disorders
  decreased appetite 18 (16) 2 (2) 12 (11) 2 (2)
  dehydration 7 (6) 3 (3) 0 0
Infections and infestations
  sepsis (e) 10 (9) 10 (9) 4 (4) 4 (4)
  sinusitis 9 (8) 0 6 (6) 0
  urinary tract infection 9 (8) 1 (1) 4 (4) 2 (2)
  bronchitis 8 (7) 1 (1) 5 (5) 1 (1)
  oral herpes 6 (5) 1 (1) 3 (3) 0
Psychiatric disorders
  insomnia 10 (9) 0 7 (6) 0
Musculoskeletal and connective tissue disorders
  arthralgia 9 (8) 1 (1) 4 (4) 0
Nervous system disorders
  lethargy 6 (5) 0 2 (2) 0
(a) Diarrhea includes the following preferred terms: diarrhea, colitis.
(b) Abdominal pain includes the following preferred terms: abdominal pain, abdominal pain upper, abdominal pain lower.
(c) Pneumonia includes the terms: pneumonia, pneumonitis, lung infection, lung infiltration, pneumocystis jiroveci pneumonia, pneumonia legionella, lung infection pseudomonal, pneumonia fungal, respiratory tract infection, lower respiratory tract infection, and lower respiratory tract infection bacterial.
(d) Rash includes the following preferred terms: dermatitis exfoliative, drug eruption, rash, rash erythematous, rash generalized, rash macular, rash maculo-papular, rash papular, rash pruritic, rash morbilliform, and exfoliative rash.
(e) Sepsis includes the terms: sepsis, septic shock, neutropenic sepsis, and sepsis syndrome

Table 3. Hematologic and Hepatic Laboratory Abnormalities Reported in ≥10% of Patients with CLL and Occurred at ≥5% Higher Incidence in Patients Receiving Zydelig in Study 312-0116

  Zydelig + R
N=110 (%)
Placebo + R
N=108 (%)
Laboratory Parameter Any Grade Grade 3–4 Any Grade Grade 3–4
Hematology abnormalities
  neutropenia 71 (65) 46 (42) 61 (56) 33 (31)
  leukopenia 34 (31) 9 (8) 25 (23) 9 (8)
  lymphocytopenia 23 (21) 11 (10) 13 (12) 4 (4)
Serum chemistry abnormalities
  ALT increased 43 (39) 10 (9) 13 (12) 1 (1)
  AST increased 31 (28) 6 (5) 16 (15) 0

After closure of Study 312-0116, 71 patients continued treatment with Zydelig on an extension study (Study 312-0117; NCT01539291). The median duration of exposure was 18 months. Serious adverse reactions occurred in 48 (68%) patients. The most frequent serious adverse reactions reported were pneumonia (30%), diarrhea (15%), and pyrexia (11%).

The most frequent adverse reactions were pneumonia (51%), pyrexia (46%), and cough (45%). The most frequent Grade 3 or greater adverse reactions were pneumonia (30%), diarrhea (15%), and sepsis (10%).

Zydelig with Ofatumumab (Study 312-0119; NCT01659021)

In Study 312-0119, 259 patients with relapsed CLL received up to 12 doses of ofatumumab with or without Zydelig 150 mg twice daily. The median duration of exposure to Zydelig was 13.9 months.

Serious adverse reactions were reported in 133 (77%) patients treated with Zydelig + ofatumumab. The most frequent serious adverse reactions reported were pneumonia (14%), pyrexia (13%), and diarrhea (12%).

Adverse reactions that led to discontinuation of Zydelig occurred in 71 (41%) patients. One hundred and ten (64%) patients had dose interruptions and 42 (24%) patients had dose reductions due to adverse reactions or laboratory abnormalities. The most common reasons for dose discontinuations, reductions, or interruptions were diarrhea and colitis. The most common adverse reactions were diarrhea (55%), pyrexia (38%), nausea (34%), and fatigue (34%).

Zydelig with Bendamustine and Rituximab (Study 312-0115; NCT01569295)

In Study 312-0115, patients with relapsed CLL received up to 6 cycles of bendamustine and rituximab (BR) with or without Zydelig 150 mg twice daily. The median duration of exposure to Zydelig was 18.2 months.

Serious adverse reactions were reported in 147 (71%) patients treated with Zydelig + BR. The most frequent serious adverse reactions reported for patients treated with Zydelig + BR were febrile neutropenia (21%), pneumonia (17%), pyrexia (12%), and diarrhea (6%).

Adverse reactions that led to discontinuation of Zydelig occurred in 68 (33%) patients. The most common adverse reactions that led to treatment discontinuations were pneumonia, diarrhea, and pyrexia.

One hundred twenty-two (59%) patients treated with Zydelig + BR had dose interruptions and 34 (16%) patients had dose reductions due to adverse reactions. The most common reasons for dose interruptions or reductions were increased ALT and diarrhea. The most common adverse reactions were neutropenia (64%), pyrexia (43%), and diarrhea (41%).

Summary Of Clinical Trials In Indolent Non-Hodgkin Lymphoma

The safety data reflect exposure to Zydelig from three open-label clinical trials (Studies 101-09 (NCT01282424), 101-02 (NCT00710528), and 101-10 (NCT01306643) in 146 patients with indolent non-Hodgkin lymphoma (iNHL) treated with Zydelig 150 mg twice daily [see Clinical Studies]. The median duration of exposure was 6.1 months (range 0.3 to 26.4 months).

Serious adverse reactions were reported in 73 (50%) patients. The most frequent serious adverse reactions that occurred were pneumonia (15%), diarrhea (11%), and pyrexia (9%).

Adverse reactions resulted in interruption or discontinuation for 78 (53%) patients. The most common reasons for interruption or discontinuations were diarrhea (11%), pneumonia (11%), and elevated transaminases (10%).

Table 4 provides the adverse reactions occurring in at least 10% of patients receiving Zydelig monotherapy, and Table 5 provides the hematologic and hepatic laboratory abnormalities.

Table 4. Adverse Reactions Reported in ≥ 10% of Patients with Indolent NHL Treated with Zydelig 150 mg BID

  Zydelig Monotherapy
N=146 (%)
Adverse Reaction Any Grade Grade ≥3
Gastrointestinal disorders
  diarrhea (a) 68 (47) 20 (14)
  nausea 42 (29) 2 (1)
  abdominal pain (b) 38 (26) 3 (2)
  vomiting 22 (15) 2 (1)
General disorders and administration site conditions
  fatigue 44 (30) 2 (1)
  pyrexia 41 (28) 3 (2)
  asthenia 17 (12) 3 (2)
  peripheral edema 15 (10) 3 (2)
Respiratory, thoracic, and mediastinal disorders
  cough 42 (29) 1 (1)
  pneumonia (c) 37 (25) 23 (16)
  dyspnea 25 (17) 6 (4)
Skin and subcutaneous disorders
  rash (d) 31 (21) 4 (3)
  night sweats 18 (12) 0
Metabolism and nutrition disorders
  decreased appetite 24 (16) 1 (1)
Infections and infestations
  upper respiratory tract infection 18 (12) 0
Psychiatric disorders
  insomnia 17 (12) 0
Nervous system disorders
  headache 16 (11) 1 (1)
(a) Diarrhea includes the following preferred terms: diarrhea, colitis, enterocolitis, and gastrointestinal inflammation.
(b) Abdominal pain includes the following preferred terms: abdominal pain, abdominal pain upper, abdominal pain lower, and abdominal discomfort.
(c) Pneumonia includes the terms: pneumonia, pneumonitis, interstitial lung disease, lung infiltration, pneumonia aspiration, respiratory tract infection, atypical pneumonia, lung infection, pneumocystis jiroveci pneumonia, bronchopneumonia, pneumonia necrotizing, lower respiratory tract infection, pneumonia pneumococcal, pneumonia staphylococcal, pneumonia streptococcal, pneumonia cytomegaloviral, and respiratory syncytial virus infection.
(d) Rash includes the following preferred terms: dermatitis exfoliative, rash, rash erythematous, rash macular, rash maculo-papular, rash pruritic, and exfoliative rash.

Table 5. Hematologic and Hepatic Laboratory Abnormalities in Patients with Indolent non-Hodgkin Lymphoma Treated with Zydelig 150 mg BID

  Zydelig Monotherapy
N=146 (%)
Laboratory Abnormality Any Grade Grade 3 Grade 4
Serum chemistry abnormalities
  ALT increased 73 (50) 20 (14) 7 (5)
  AST increased 60 (41) 12 (8) 6 (4)
Hematology abnormalities
  neutrophils decreased 78 (53) 20 (14) 16 (11)
  hemoglobin decreased 41 (28) 3 (2) 0
  platelets decreased 38 (26) 4 (3) 5 (3)
Grades were obtained per CTCAE version 4.03.

Summary Of Discontinued Clinical Trials In First-Line CLL And Early Line iNHL

Safety data described below reflect exposure to Zydelig in three randomized, double-blind clinical trials (Studies 312-0123, 313-0124, and 313-0125) in patients with CLL and iNHL.

In Study 312-0123 (NCT01980888), 311 patients with previously untreated CLL received up to 6 cycles of BR with or without Zydelig 150 mg twice daily.

In Study 313-0124 (NCT01732913), 295 patients with previously treated iNHL received 8 doses of R with or without Zydelig 150 mg twice daily. Patients had a median of one prior therapy.

In Study 313-0125 (NCT01732926), 475 patients with previously treated iNHL received up to 6 cycles of BR with or without Zydelig 150 mg twice daily. Patients had a median of two prior therapies.

These three studies were terminated early due to a higher incidence of fatal and/or serious adverse reactions observed in patients treated with Zydelig in combination with R or BR. The most frequent serious adverse reactions were in the system organ classes of infections and infestations, blood and lymphatic system disorders, and gastrointestinal disorders.

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)

Drug Interactions

DRUG INTERACTIONS

Effects Of Other Drugs On Zydelig

Table 6. Drug Interactions with Zydelig that affect Idelalisib Concentrations

Strong CYP3A Inhibitors
Clinical Impact
  • Coadministration with strong CYP3A inhibitors may increase idelalisib concentrations [see CLINICAL PHARMACOLOGY].
  • Increased idelalisib concentrations may increase the risk of exposure related adverse reactions.
Prevention or Management
  • Use other drugs that are not strong CYP3A inhibitors.
  • If unable to use alternative drugs, monitor patients more frequently for Zydelig adverse reactions [see WARNINGS AND PRECAUTIONS].
Strong CYP3A Inducers
Clinical Impact
  • Coadministration with strong CYP3A inducers may decrease idelalisib concentrations [see CLINICAL PHARMACOLOGY].
  • Decreased idelalisib concentrations may reduce efficacy.
Prevention or Management Avoid coadministration of Zydelig with strong CYP3A4 inducers.

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].

Warnings & Precautions

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Hepatotoxicity

Fatal and/or serious hepatotoxicity occurred in 18% of patients treated with Zydelig monotherapy and 11% of patients treated with Zydelig in combination trials. Elevations in ALT or AST greater than 5 times the upper limit of normal have occurred [see ADVERSE REACTIONS]. 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].

Severe Diarrhea Or Colitis

Severe diarrhea or colitis (Grade 3 or higher) occurred in 14% of patients treated with Zydelig monotherapy and 19% of patients treated with Zydelig in combination trials [see ADVERSE REACTIONS]. 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].

Pneumonitis

Fatal and serious pneumonitis occurred in patients treated with Zydelig. 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. 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 should be evaluated for pneumonitis. If pneumonitis is suspected, interrupt Zydelig until the etiology of the pulmonary symptoms has been determined. Patients with pneumonitis thought to be caused by Zydelig have been treated with discontinuation of Zydelig and administration of corticosteroids.

Infections

Fatal and/or serious infections occurred in 21% of patients treated with Zydelig monotherapy and 36% of patients treated with Zydelig in combination trials. The most common infections were pneumonia, sepsis, and febrile neutropenia. Monitor patients for signs and symptoms of infection and interrupt Zydelig for Grade 3 or higher infection [see DOSAGE AND ADMINISTRATION].

Serious or fatal Pneumocystis jirovecii pneumonia (PJP) or cytomegalovirus (CMV) occurred in <1% of patients treated with Zydelig. Consider prophylaxis for PJP. Interrupt Zydelig in patients with suspected PJP infection of any grade, and permanently discontinue Zydelig if PJP infection of any grade is confirmed. Interrupt Zydelig in the setting of positive CMV PCR or antigen test until the infection 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].

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.

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.

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.

Neutropenia

Treatment-emergent Grade 3 or 4 neutropenia occurred in 25% of patients treated with Zydelig monotherapy and 46% of patients treated with Zydelig in combination trials. 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].

Embryo-fetal Toxicity

Based on findings in animals, Zydelig may cause fetal harm when administered to a pregnant woman. Idelalisib is teratogenic in rats, at systemic exposures 12 times those reported in patients at the recommended dose of 150 mg twice daily. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [see Use In Specific Populations].

Advise females of reproductive potential to avoid becoming pregnant while taking Zydelig. If contraceptive methods are being considered, use effective contraception during treatment, and for at least 1 month after the last dose of Zydelig [see Use In Specific Populations].

Patient Counseling Information

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

Physicians and health care professionals are advised to discuss the following with patients prior to treatment with Zydelig:

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]. 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].

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].

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].

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].

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].

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].

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].

Pregnancy And Nursing

Advise women of the potential hazard to the fetus and to avoid pregnancy during treatment with Zydelig. If contraceptive methods are being considered, advise to use adequate contraception during therapy and for at least one month after completing therapy. Also advise patients not to breastfeed while taking Zydelig [see WARNINGS AND PRECAUTIONS and Use In Specific Populations].

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.

Nonclinical Toxicology

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.

Use In Specific Populations

Pregnancy

Pregnancy Category D [see WARNINGS AND PRECAUTIONS]

Risk Summary

Based on findings in animals, Zydelig may cause fetal harm when administered to a pregnant woman. Idelalisib was teratogenic in animals. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus.

Animal Data

In an embryo-fetal development study, pregnant rats were administered oral doses of idelalisib during the period of organogenesis at 25, 75, and 150 mg/kg/day. Embryo- fetal toxicities were observed at the mid-and high-doses that also resulted in maternal toxicity, based on reductions in maternal body weight gain. Adverse findings at idelalisib doses ≥ 75 mg/kg/day included decreased fetal weights, external malformations (short tail), and skeletal variations (delayed ossification and/or unossification of the skull, vertebrae, and sternebrae). Additional findings were observed at 150 mg/kg/day dose of idelalisib and included urogenital blood loss, complete resorption, increased post-implantation loss, and malformations (vertebral agenesis with anury, hydrocephaly, and microphthalmia/anophthalmia). The dose of 75 and 150 mg/kg/day of idelalisib in rats resulted in exposures (AUC) of approximately 12 and 30 times, respectively, the human exposure at the recommended dose of 150 mg twice daily.

Nursing Mothers

It is not known whether idelalisib is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Zydelig, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

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

Geriatric Use

In clinical trials of Zydelig in patients with FL, SLL, and CLL, 131/208 (63%) patients were age 65 and older. No major differences in effectiveness were observed. In patients 65 years of age or older with indolent non-Hodgkin lymphoma in comparison to younger patients, 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%). In patients 65 years of age or older with CLL in comparison to younger patients, older patients had a higher incidence of discontinuation due to an adverse reaction (11% vs 5%), higher incidence of serious adverse reactions (51% vs 43%), and higher incidence of death (3% vs 0%).

Females Of Reproductive Potential

Contraception

Zydelig may cause fetal harm when administered during pregnancy. Advise females of reproductive potential to avoid becoming pregnant while taking Zydelig. If contraceptive methods are being considered, use effective contraception while taking Zydelig and for at least one month after taking the last dose of Zydelig. Advise patients to contact their healthcare provider if they become pregnant, or if pregnancy is suspected, while taking Zydelig [see Use In Specific Populations].

Renal Impairment

No dose adjustment of Zydelig is necessary for patients with creatinine clearance (CrCl) ≥ 15 mL/min [see CLINICAL PHARMACOLOGY].

Hepatic Impairment

The AUC of idelalisib increased up to 1.7-fold in subjects with ALT or AST or bilirubin greater than the upper limit of normal (ULN) compared to healthy subjects with normal ALT or AST or bilirubin values [see CLINICAL PHARMACOLOGY]. Safety and efficacy data are not available in patients with baseline ALT or AST values greater than 2.5 x ULN or bilirubin values greater than 1.5 x ULN, as these patients were excluded from Studies 1 and 2. Patients with baseline hepatic impairment should be monitored for signs of Zydelig toxicity [see WARNINGS AND PRECAUTIONS]. Follow dose modifications for adverse reactions [see DOSAGE AND ADMINISTRATION].

Overdosage & Contraindications

OVERDOSE

No Information provided

CONTRAINDICATIONS

History of serious allergic reactions including anaphylaxis and toxic epidermal necrolysis.

Clinical Pharmacology

CLINICAL PHARMACOLOGY

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.

Pharmacodynamics

Cardiac Electrophysiology

At a dose 2.7 times the maximum recommended dose, Zydelig did not prolong the QT/QTc interval (i.e., ≤10 ms).

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.

Absorption

The median time to peak concentration (Tmax) was observed at 1.5 hours.

Food Effect

The administration of a single dose of Zydelig with a high-fat meal (900 calories: 525 calories fat, 250 calories carboydrates, and 125 calories protein) increased idelalisib AUC 1.4-fold relative to fasting conditions. Zydelig can be administered without regard to food.

Distribution

Protein binding of idelalisib is ≥ 84% with no concentration dependence.

The mean blood-to-plasma ratio was 0.7.

The apparent central volume of distribution at steady state is 23 L (%CV ~85%).

Idelalisib is a substrate of P-glycoprotein (P-gp) and BCRP in vitro.

Elimination

The population apparent systemic clearance at steady-state is 14.9 L/hr (%CV ~ 38%). The population terminal elimination half-life of idelalisib is 8.2 hours.

Metabolism

Idelalisib is metabolized via aldehyde oxidase and CYP3A with additional minor metabolism by UGT1A4.

Excretion

Following a single 150 mg dose of radiolabeled idelalisib, 78% of the radioactivity was excreted in feces and 14% was excreted in the urine. Idelalisib is not a substrate of OATP1B1, OATP1B3, OAT1, OAT3, or OCT2.

Specific Populations

Age (18 to 91 years), sex, race (White, and non-Whites), renal impairment (creatinine clearance ≥ 15 mL/min) and weight (38 to 148 kg) had no effect on idelalisib exposure.

Pediatric Patients

The pharmacokinetics of idelalisib in pediatric patients is unknown.

Patients With Hepatic Impairment

The mean AUC increased up to 1.7-fold in patients with hepatic impairment (defined as ALT or AST or bilirubin values ≥ ULN) compared to patients with normal hepatic function. There is limited information on idelalisib exposure in patients with baseline AST or ALT > 2.5 × ULN or bilirubin > 1.5 × ULN [see Specific Populations].

Drug Interaction Studies

Effect Of Other Drugs On Idelalisib

The coadministration of rifampin (strong CYP3A inducer and P-gp inducer) to healthy subjects decreased the mean idelalisib AUC by 75% and the mean Cmax by 58% [see DRUG INTERACTIONS].

The coadministration of ketoconazole (strong CYP3A inhibitor and P-gp inhibitor) to healthy subjects increased the mean idelalisib AUC by 1.8-fold. No changes in the mean Cmax were observed [see DRUG INTERACTIONS].

In vitro studies suggest that idelalisib inhibits CYP2C8, CYP2C19, and UGT1A1 and induces CYP2B6.

Effect Of Idelalisib On Other Drugs

The mean Cmax of midazolam increased by 2.4-fold and the mean AUC of midazolam increased by 5.4-fold when midazolam (sensitive CYP3A substrate) was coadministered with Zydelig [see DRUG INTERACTIONS].

No changes in exposure to rosuvastatin (OATP1B1 and OATP1B3 substrate) or digoxin (P-glycoprotein substrate) were observed when coadministered with Zydelig.

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.

Clinical Studies

Relapsed Chronic Lymphocytic Leukemia

Study 312-0116

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 oral placebo twice daily or with Zydelig 150 mg taken twice daily until disease progression or unacceptable toxicity.

In Study 312-0116, the median age was 71 years (range 47, 92) with 78% over 65, 66% were male, and 90% were Caucasian. 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 (eCrCl) was 63.6 mL/min, with 41% of patients having an eCrCl 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 evaluated by 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 over placebo + R for the primary endpoint 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.

Table 7 Efficacy Results from Study 312-0116

  Zydelig + R
N=110
Placebo + R
N=110
PFS Median (months) (95% CI) 19.4 (12.3, NR) 6.5 (4.0, 7.3)
Hazard ratio (95% CI) 0.15 (0.09, 0.24)
P-value < 0.0001
ORR* (All PRs) 92 (83.6%) 17 (15.5%)
95% CI 75.4, 90.0 9.3, 23.6
Odds Ratio (95% CI) 27.8 (13.4, 57.5)
P-value <0.0001
DOR Median (months) (95% CI) NR (12, NR) 6.2 (2.8, 6.5)
PFS: progression-free survival; NR: not reached; ORR: overall response rate; PR: partial response; DOR: duration of response
The p value for PFS was based on stratified log-rank test.
* ORR defined as the proportion of patients who achieved a complete response (CR) or PR. All PRs achieved; none of the patients achieved a CR.

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

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

Relapsed Follicular B-Cell Non-Hodgkin Lymphoma

Study 101-09

The safety and efficacy of Zydelig in patients with FL was evaluated in a single-arm, multicenter study 101-09 (NCT01282424) which included 72 patients with follicular B-cell non-Hodgkin lymphoma who had relapsed within 6 months following rituximab and an alkylating agent and had received at least 2 prior treatments. The median age was 62 years (range 33 to 84), 54% were male, and 90% were Caucasian. At enrollment, 92% of patients had a baseline ECOG performance status of 0 or 1. The median time since diagnosis was 4.7 years and the median number of prior treatments was 4 (range 2 to 12). The most common prior combination regimens were R-CHOP (49%), BR (50%), and R-CVP (28%). At baseline, 33% of patients had extranodal involvement and 26% had bone marrow involvement.

Patients received 150 mg of Zydelig orally twice daily until evidence of disease progression or unacceptable toxicity. Tumor response was assessed according to the revised International Working Group response criteria for malignant lymphoma. The primary endpoint was Independent Review Committee-assessed overall response rate (ORR). Efficacy results are summarized in Table 8.

Table 8 Overall Response Rate (ORR) and Duration of Response (DOR) in Patients with Relapsed Follicular Lymphoma

  N=72
ORR 39 (54%)
  95% CI (42, 66%)
  CR 6 (8%)
  PR 33 (46%)
Median* DOR, months (range) median not evaluable (0.0+, 14.8+)
CI = confidence interval; CR = complete response; PR = partial response
* Kaplan-Meier estimate

The median time to response was 1.9 months (range 1.6–8.3).

Relapsed Small Lymphocytic Lymphoma

Study 101-09

The safety and efficacy of Zydelig in patients with SLL was evaluated in a single-arm, multicenter study 101-09 (NCT01282424) which included 26 patients with small lymphocytic lymphoma who had relapsed within 6 months following rituximab and an alkylating agent and had received at least 2 prior treatments. The median age was 65 years (range 50 to 87), 73% were male, and 81% were Caucasian. At enrollment, 96% of patients had a baseline ECOG performance status of 0 or 1. The median time since diagnosis was 6.7 years and the median number of prior treatments was 4 (range 2 to 9). The most common prior combination regimens were BR (81%), FCR (62%) and R-CHOP (35%). At baseline, 27% of patients had extranodal involvement.

Patients received 150 mg of Zydelig orally twice daily until evidence of disease progression or unacceptable toxicity. Tumor response was assessed according to the revised International Working Group response criteria for malignant lymphoma. The primary endpoint was Independent Review Committee-assessed overall response rate (ORR). Efficacy results are summarized in Table 9.

Table 9 Overall Response Rate (ORR) and Duration of Response (DOR) in Patients with Relapsed Small Lymphocytic Lymphoma

  N=26
ORR 15 (58%)
  95% CI (37, 77%)
  CR 0
  PR 15 (58%)
Median* DOR, months (range) 11.9 (0.0+, 14.7+)
CI = confidence interval; CR = complete response; PR = partial response
* Kaplan-Meier estimate

The median time to response was 1.9 months (range 1.6–8.3).

Medication Guide

PATIENT INFORMATION

No information provided. Please refer to the WARNINGS AND PRECAUTIONS sections.

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