Trial Treating Relapsed Acute Lymphoblastic Leukemia With Venetoclax and Navitoclax

This is a non-randomized phase I/II clinical trial. In Block I, all patients receiving common therapy evaluating the activity of combination chemotherapy with venetoclax and navitoclax in children with relapsed or refractory acute lymphoblastic leukemia or lymphoma (rALL).

In Block 2, a phase 1 rolling six design and phase 2 extension will be used to assess the combination dose of venetoclax combinations with either blinatumomab for CD19-positive patients or navitoclax and high-dose cytarabine for CD19-negative patients. One to six participants can be concurrently enrolled onto a dose level, depending on the number of participants enrolled at the current dose level, the number of participants who have experienced a dose/combination limiting toxicity (DLT) at the current dose level, and the number of participants entered but with tolerability data pending. Dose de-escalation will occur if 2 patients at a dose level experience a targeted toxicity. If 6 patients complete a therapy block and experience 0-1 DLT, that dose will be considered the recommended phase 2 dose (RP2D). New enrollment on an arm (2a/2b) will be paused if further enrollment would result in more than 6 patients being treated on that arm before the RP2D is identified.

The primary outcome assessment will be a bone marrow with MRD testing on Day 29 of Block 1 therapy. Following that assessment, patients should continue with protocol therapy including either Block 2A (which includes high-dose cytarabine with venetoclax and navitoclax) for patients with CD19 negative leukemia, those with isolated extramedullary relapse, or whose treating physician determines that blinatumomab therapy is not in the patient's best interest; or Block 2B for patients with leukemia which is CD19 positive. Following recovery from Block 2 therapy, all patients except those with late first relapse of B-ALL (≥ 36 months from diagnosis) who are MRD-negative at <0.01% after Block 1 therapy are off therapy. Further therapy for these patients is at the treating physician's discretion. Patients with late first relapse B-ALL relapse and who are MRD negative will proceed with intensification, interim continuation, and continuation therapy. Patients with Down's Syndrome with CD19 negative leukemia will be off therapy after Block 1 as they are ineligible for Block 2A. Patients in exploratory cohorts I and N who are late first relapse B-ALL and who are MRD-negative after Block 1 therapy may continue on protocol therapy after Block 2 or receive alternative therapy at their treating physician's discretion. Patients in exploratory cohort M and O are off therapy after Block 2.

Intervention:

Block 1 Therapy:

• Venetoclax 120mg/m^2 (max 200mg) PO, day 1; 240mg/m^2/dose (max 400mg) PO, 21 doses, days 2-22
• Navitoclax 25mg PO (for patients 20 - <45kg) OR 50mg PO (for patients >=45kg), days 3-22
• Dexamethasone 5mg/m^2/dose BID PO/IV, days 1-7 and 15-22
• Vincristine 1.5mg/m^2/dose (max 2mg) IV, days 1, 8, 15, and 22
• Calaspargase pegol 2500units/m^2/dose IV, day 2
• Dasatinib 80mg/m^2/day (max 140mg) PO, days 1-28 for ABL-class fusions and non-ETP T-ALL
• IT MHA: Intrathecal (IT) MHA (methotrexate 12 mg/hydrocortisone 24mg/cytarabine 36mg), days -7 to 1. Continue intrathecal chemotherapy weekly until negative x 2.
• Leucovorin 5mg/m2 (max 5mg) PO or IV (24 and 30 hours after each LP).

Calaspargase may be replaced by alternative forms of asparaginase due to local practice or prior allergy. If pegaspargase is used, two doses (on days 2 and 15) of 2500units/ m^2 replace the single day 2 dose of calaspargase. For patients in exploratory cohort N, asparaginase will be omitted. For patients in exploratory cohort O, the Day 15 dose of pegaspargase may be omitted and the Day 2 dose may be capped at 2000units/m2 with a maximum dose of 3750 units.

Testicular Radiation: Patients with persistent testicular involvement by leukemia at the end of Block 1 may continue on study and may receive testicular radiation during Block 2 therapy.

Block 2a - For patients with ≥ 5% of leukemic blasts which do not have detectable CD19 on their surface, those with isolated extramedullary relapse, or whose physician determines this therapy arm is in their patient's best interest. Patients with Down Syndrome are not eligible for Block 2a therapy. Patients in exploratory cohort O are not eligible for the phase I/dose de-escalation phase of the study but may enroll on block 2 therapy after the dose has been established.:

• Venetoclax 240mg/m^2 (max 400mg) PO, days 1-7
• Navitoclax 25mg (20-<45kg) OR 50mg (>=45kg) PO, days 1-7
• Dexamethasone 3mg/m^2/dose PO/IV BID, days 1-5
• Calaspargase pegol 1000units/m^2 IV, day 3
• Dasatinib 80mg/m2/day (max 140mg) PO, days 1-28 for ABL-class fusion and non-ETP T-ALL/ALLy
• IT MHA: Methotrexate 12 mg IT, Hydrocortisone 24mg IT, Cytarabine 36mg IT, one dose with end of cycle bone marrow assessment
• Cytarabine dosing during phase I portion for Block 2a:

• Dose level 1: 3000mg/m^2/dose every 12hours(h) IV infusion over 3 hours, days 1-2
• Dose level 0: 1500mg/m^2/dose every 12h IV infusion over 3 hours, days 1-2
• Dose level -1: 1000mg/m^2/dose every 12h IV infusion over 3 hours, day 1

Calaspargase may be replaced by alternative forms of asparaginase. For patients in exploratory cohort N, asparaginase will be omitted.

Block 2b Therapy: For patients with >95% of leukemic blasts with detectable CD19 on their surface. Patients with isolated extramedullary relapse are ineligible for Block 2b therapy. Patients in exploratory cohort O are not eligible for the phase I/ dose de-escalation phase of the study but may enroll on block 2 therapy after the dose has been established.

• Blinatumomab; for patients with end of Block 1 MRD >5%, 5mcg/m^2/day (max 9mcg/day; patients weighing ≥45kg receive 9mcg/day fixed dose) IV, days 1-7
• Blinatumomab; for patients with end of Block 1 MRD >5%, 15mcg/m^2/day (max 28mcg/day; patients weighing ≥45kg receive 28mcg/day fixed dose) IV, days 8-28
• Blinatumomab; for patients with end of Block 1 MRD ≤5%, 15mcg/m^2/day (max 28mcg/day; patients weighing ≥45kg receive 28mcg/day fixed dose) IV, days 1-28,
• Dexamethasone 10mg/m^2 (max 20mg) 30-60 minutes prior to day 1 blinatumomab, PO/IV, days 1, 8 (For patients who start blinatumomab at 5mcg/m2/day, an additional dose of dexamethasone will be given on day 8 30-60 minutes prior to dose increase. For patients whose blinatumomab is interrupted for more than 4 hours for any reason, an additional dose of dexamethasone will be given prior to restarting blinatumomab.)
• Dasatinib 80mg/m^2/day (max 140mg) PO, days 1-28 for ABL-class fusions
• IT MHA: Methotrexate 12 mg IT, Hydrocortisone 24mg IT, Cytarabine 36mg IT, day 29 with end of cycle bone marrow
• Venetoclax dosing during phase I portion for Block 2b:

• Dose level 1: 240mg/m^2 (max 400 mg) PO, days 8-28
• Dose level 0: 240mg/m^2 (max 400 mg) PO, days 8-21
• Dose level -1: 240mg/m^2 (max 400 mg) PO, days 8-14

Intensification Therapy - For late first relapse B-ALL and MRD<0.01% after Block 1 only. Patients in exploratory cohort O are excluded.:

• High Dose (HD) Methotrexate 5000mg/m^2/dose IV: 500mg/m^2 over 60 minutes then 4500mg/m^2 over 23 hours; or targeted 65 microM, day 1 and 15
• Mercaptopurine 50mg/m^2/dose PO daily, days 1-28
• IT MHA: Methotrexate 12 mg IT, Hydrocortisone 24mg IT, Cytarabine 36mg IT, D15
• Leucovorin 15mg/m2/dose PO/IV every 6 hours (start 42 hours after HD-MTX begins) D2 and 16 (at least 3 doses).

Interim Continuation Therapy 1 and 2 (8 weeks each) - For late first relapse B-ALL and MRD<0.01% after Block 1 only:

• Dexamethasone 3mg/m^2/dose BID PO/IV, days 1-5
• Vincristine1.5mg/m^2(max 2mg) IV, day 1
• Mercaptopurine 75mg/m^2/dose PO daily or 60mg/m2/day for patients with known heterozygous inactivating mutations of TPMT or NUDT15, days 1-49
• Methotrexate 20mg/m^2/dose PO/IV, days 8, 15, 29, 36
• High Dose (HD)-Methotrexate 5000mg/m^2/dose IV: 500mg/m2 over 60 minutes then 4500mg/m^2 over 23 hours; or targeted 65 microM, day 22
• Leucovorin 15mg/m^2/dose PO/IV every 6 hours: Start 42 hours after HD-MTX, days 24 and 25 (at least 3 doses)
• Cyclophosphamide 300mg/m^2/dose IV over 15-30 minutes, days 43 and 50
• Etoposide 150mg/m^2/dose IV over 1-2 hours, days 43 and 50
• Cytarabine 50mg/m^2/dose IV over 1-30 minutes, days 44-47 and 51-54
• Dasatinib 80mg/m^2/day PO (Max 140mg), days 1-56 for ABL-class fusions
• IT MHA: Methotrexate 12 mg IT, Hydrocortisone 24mg IT, Cytarabine 36mg IT, days 22 and 43

Following recovery from Interim Continuation therapy 1, patients will repeat Block 2 therapy according to their initial Block assignment (2A for CD19-negative, 2B for CD19-positive) and receive a second cycle of interim continuation. Patients will not receive venetoclax or navitoclax during this repeated Block 2 cycle. Following recovery from Interim Continuation 2, patients will proceed to Continuation therapy.

Continuation Therapy - For late first relapse B-ALL and MRD <0.01% after Block 1 only. Continuation cycles last 8 weeks (56 days) each. Continuation therapy continues until 2 years from the start of protocol therapy.:

• Dexamethasone 6mg/m^2/dose BID PO/IV, days 1-5, 29-33
• Vincristine 1.5mg/m^2 (max 2mg) IV, day 1 and 29
• Mercaptopurine 75mg/m^2/dose PO daily or 60mg/m^2/day for patients with known heterozygous inactivating mutations of TPMT or NUDT15 days 1-56
• Methotrexate 20mg/m^2/dose PO/IV days 8, 15, 22, 36, 43 and 50
• Dasatinib 80mg/m^2/day PO (Max 140mg) days 1-56 for ABL-class fusions
• IT MHA: Methotrexate 12 mg IT, Hydrocortisone 24mg IT, Cytarabine 36mg IT day 1 and 29 (patients with CNS2 or traumatic lumbar puncture with blasts present at the time of relapse will receive day 1 and 29 IT MHA for the first year of continuation therapy. Following this, patients will receive IT MHA on day 1 of each cycle until the completion of therapy. Patients with CNS3 disease at relapse will receive day 1 and 29 IT MHA during cycles 1 and 2 of continuation and then proceed to chemoradiation.)

Chemoradiation for those with CNS3 disease at relapse (late first relapse [≥36 months from diagnosis] B-ALL and MRD<0.01% after Block 1 only):

Patients with CNS3 disease at relapse will receive 18Gy cranial irradiation after Cycle 2 of Continuation Therapy. Patients will not receive additional intrathecal chemotherapy following irradiation. Chemoradiation lasts 21 days.

• Dexamethasone 6mg/m2/dose BID PO/IV days 1-5 and 15-19
• Vincristine 1.5mg/m^2 (max 2mg) IV days 1, 8 and 15
• Calaspargase 2500units/m^2/dose IV, Day 2 (Calaspargase may be replaced by alternative forms of asparaginase and will be omitted for patients in exploratory cohort N)
• Dasatinib 80mg/m^2/day PO (Max 140mg) days 1-21 for ABL-class fusions

Inclusion criteria

• Diagnosis:

• Relapsed or refractory acute lymphoblastic leukemia or lymphoma with ≥1% bone marrow disease as measured by flow cytometry, PCR, or next generation sequencing. However, if an adequate bone marrow sample cannot be obtained, patients may be enrolled if there is unequivocal evidence of leukemia with ≥ 5% blasts in the peripheral blood.
• Patients with 1-4.99% bone marrow involvement must have disease confirmed in one of the following ways: an alternative minimal residual disease assay (e.g. flow cytometry and PCR or NGS), cytogenetic abnormality consistent with patient's leukemia, FISH abnormality, or a second bone marrow with MRD ≥1% separated by 1-4 weeks.
• Patients with ≥5% bone marrow disease by a single measurement as measured by flow cytometry, PCR, or next generation sequencing do not require a second confirmatory test.
• Refractory disease is defined as residual leukemia ≥1% after at least 2 prior lines of frontline therapy with curative intent.
• Patients in exploratory cohort I must have measurable extramedullary disease but may have <1% bone marrow disease.
• Patients in exploratory cohort M must have ≥1% bone marrow disease as measured by flow cytometry of mixed phenotype acute leukemia (MPAL)/ acute leukemia of ambiguous lineage (ALAL).
• Age ≥4 to < 30 years. Patients ≥ 22 years old are only eligible for exploratory cohort O. Sites may have different (lower) maximum ages based on institutional guidelines but may not exceed 30 years.
• Patient weighs ≥ 20 kg.
• Patient is able to swallow pills.
• Lansky/Karnofsky score is ≥ 60%. The Lansky performance score should be used for participants < 16 years and the Karnofsky performance score for participants ≥ 16 years.
• Participant has adequate organ function as defined by the following:

• Direct bilirubin ≤ 1.5x the institutional upper limit of normal (ULN) unless attributable to leukemic involvement. At institutions which do not obtain a direct bilirubin in patients with a normal total bilirubin, a normal total bilirubin may be used as evidence that the direct bilirubin is not > 1.5x the ULN. Patients with a direct bilirubin ≥ 2 mg/dl may not enroll regardless of attribution.
• Aspartate transaminase (AST) and alanine transaminase (ALT) < 3.0 x the ULN unless increase is attributable to leukemic involvement.
• Normal creatinine for age or a calculated creatinine clearance ≥ 60 mL/min/1.73 m^2.
• Left ventricular ejection fraction (LVEF) ≥ 40% or shortening fraction ≥ 25%.

• Patients with a history of reduced LVEF which subsequently improved with medical management are eligible if they meet the criteria above.
• Patients must have fully recovered from the acute effects of all prior therapy (defined as resolution of all such toxicities to ≤ Grade 2).
• For patients with prior hematopoietic stem cell transplant (HSCT), at least 90 days must have elapsed since transplant, the patient cannot have evidence of active graft-versus-host disease (GVHD), and they must be off calcineurin inhibitors for ≥4 weeks, and off other immunosuppression for ≥2 weeks.
• Patients with Down Syndrome/ germline Trisomy 21 are eligible for Block 1 and Block 2b therapies but are ineligible for Block 2a therapy. Patients with Down Syndrome and CD19-negative disease are off therapy after the response evaluation to Block 1.
• Prior therapy

• ≥14 days must have elapsed since the completion of cytotoxic therapy, with the exception of standard maintenance therapy (glucocorticoids, vincristine, methotrexate, 6-mercaptopurine), tyrosine kinase inhibitors, and steroids.
• Cytoreduction with prednisone, methylprednisolone, or hydroxyurea for ≤ 120 hours (5 days) in patients with hyperleukocytosis or extramedullary disease compromising organ function can be initiated and continued until up to 24 hours prior to the start of protocol therapy.
• At least 21 days must have elapsed since completion of therapy with a biologic agent excluding blinatumomab. For agents that have known adverse events occurring beyond 21 days after administration, this period prior to enrollment must be extended beyond the time during which adverse events are known to occur. At least 7 days must have elapsed since blinatumomab infusion and patients must have recovered from all toxicities as described above.
• Intrathecal cytotoxic therapy: No waiting period is required for patients having received intrathecal cytarabine, methotrexate, and/or hydrocortisone. Intrathecal chemotherapy given at the time of diagnostic LP to evaluate for relapse prior to study enrollment is allowed.
• Patient has not had prior exposure to navitoclax
• Male or female participant of reproductive potential must agree to use appropriate methods of contraception for the duration of study treatment and for at least 30 days after last dose of protocol treatment.
• Additional criteria for exploratory cohorts

• Cohort I: Diagnosis of isolated extramedullary relapse as defined by bone marrow blasts of <1% AND 1) central nervous system white blood cell count (WBC) of ≥ 5WBC/mL with blasts or 2) biopsy confirmed extramedullary leukemia.
• Cohort M: Diagnosis of relapsed or refractory mixed phenotype acute leukemia (MPAL)/ acute leukemia of ambiguous lineage (ALAL).
• Cohort N: Patients with relapsed or refractory ALL who, in the view of the provider, are unable to tolerate further asparaginase therapy due to prior toxicities.
• Cohort O: Patients with relapsed or refractory ALL who are ages 22-29.9 years. This cohort may not enroll patients at all sites based on institutional guidelines or capacity.

Exclusion criteria

• Known HIV infection or active hepatitis B (defined as hepatitis B surface antigen-positive) or C (defined as hepatitis C antibody-positive).
• Pregnant or lactating (female participant of childbearing potential must have negative serum or urine pregnancy test required within 7 days prior to start of treatment).
• Concomitant medications and food:

• Treatment with moderate or strong cytochrome P450 3A (CYP3A) inhibitors within 3 days of starting protocol therapy.
• Treatment with moderate or strong CYP3A inducers within 7 days of starting protocol therapy.
• Administration or consumption within 3 days prior to the first dose of study drug or grapefruit or grapefruit products, Seville oranges (including marmalade containing Seville oranges), or star fruit.
• Inability or unwillingness of research participant or legal guardian/representative to give written informed consent.