RP-3500 and Olaparib in DNA Damage Repair Pathway Deficient Relapsed/Refractory Chronic Lymphocytic Leukemia

A Phase Ib/II Trial of Combination RP-3500 and Olaparib in DNA Damage Repair Pathway Deficient Relapsed/Refractory Chronic Lymphocytic Leukemia

This is an open-label, multicenter, phase Ib/II study of the combination of RP-3500 and olaparib in Relapsed/Refractory Chronic Lymphocytic Leukemia (R/R CLL) patients with DDR deficiencies.

The Phase Ib part of the trial will seek to assess the Maximum Tolerated Dose (MTD) of camonsertib (RP-3500) in combination with olaparib. Given the potential overlapping toxicities of RP-3500 and olaparib, a keyboard phase I design, a novel Bayesian method that typically underestimates the MTD,61 will be employed. The target toxicity is 30% with an equivalence interval between 25-33% of patients. With an anticipated 3 dose levels (DL) and an option for a DL-1, up to 18 patients may be required to determine the MTD. A maximum of 12 patients will be treated at a DL.

The first 5 patients treated at the previous DL1 (camonsertib 40mg daily and olaparib 100mg two times a day (BID) dosing 3 days per week) determined that this dosing strategy may not be appropriate for R/R CLL patients and reduced dosing may be necessary to increase safety of the combination therapy. Therefore, the newly proposed DLs will seek to enroll an additional 18 patients.

After completion of the phase Ib portion and assignment of the recommended phase 2 dose (RP2D), continuous enrollment of patients may commence into the phase II dose expansion portion. All patients enrolled at the RP2D during the phase Ib dose-escalation portion of the trial can be carried over into the phase II analysis. The maximum number of patients that can be carried over from the dose escalation to the dose-expansion portion is 12.

The phase II dose expansion will consist of two separate cohorts of subjects: an enrichment cohort and a cohort for all other eligible subjects. All subjects enrolled into the enrichment cohort must have a del(11q) and/or ATM mutation. Eight subjects will be enrolled into the enrichment cohort and 16 will be enrolled into the second cohort for a total phase II cohort of 24 patients.

Inclusion Criteria:

• Diagnosis of Chronic lymphocytic leukemia (CLL) according to the National Cancer Institute International Workshop on Chronic Lymphocytic Leukemia (NCI/IWCLL), criteria.

  --This includes previous documentation of:

  • Biopsy-proven small lymphocytic lymphoma/CLL

  • OR

  • Diagnosis of CLL according to the NCI/IWCLL criteria as evidenced by all of the following:

    • Peripheral blood monoclonal B cell population of greater than 5x109/L

    • Immunophenotype consistent with CLL defined as:

      • The predominant population of lymphocytes share both B cell antigens [CD19, CD20 (typically dim expression), or CD23] as well as CD5 in the absence of other pan-T-cell markers (CD3, CD2, etc).
      • Clonality as evidenced by κ or λ light chain restriction (typically dim immunoglobulin expression)

  • Negative Fluorescence in situ hybridization (FISH) analysis for t(11;14)(IgH/CCND1) on peripheral blood or tissue biopsy (e.g. marrow aspirate), or negative immunohistochemical stains for cyclin D1 on involved tissue biopsy (e.g. marrow aspirate or lymph node biopsy).

• Repeat testing of somatic mutations and FISH analysis must be performed by a Clinical Laboratory Improvement Amendments (CLIA) certified laboratory after progression is noted from most recent line of therapy and within 6 months of screening. Primary CLL cells must harbor one of these abnormalities:

  • Somatic gene mutation testing shows mutation(s) in Tumor protein P53 (TP53), Ataxia-telangiectasia mutated (ATM), Splicing factor 3b subunit 1 (SF3B1), eukaryotic nuclear export protein exportin-1 (XPO1) and/or Protection of Telomeres Protein 1 (POT1)
  • Cytogenetic FISH analysis shows deletion 17p13 and/or deletion 11q22.3

• Relapsed or refractory after at least 2 prior lines of therapy, and in the opinion of the treating Investigator are either not eligible for other approved therapies or no approved therapies are expected to have sustained therapeutic benefit.

• Patient in need of treatment or change in treatment per iwCLL criteria.

  --Patients on Bruton tyrosine kinase (BTK), Phosphoinositide 3-kinase inhibitor (PI3K) or B-cell lymphoma 2 (BCL2) inhibitors may enroll without meeting iwCLL criteria for treatment as long as there is clinical evidence of progression (i.e. increasing lymphocytosis, worsening anemia/thrombocytopenia attributable to CLL disease progression, increasing lymphadenopathy, or worsening patient symptoms) and require change in treatment at the discretion of the treating provider. Patients must still meet all other inclusion/exclusion criteria for enrollment including appropriate washout periods (5.2.2) and relapsed disease after 2 prior lines of therapy with no other approved therapies that are expected to have sustained therapeutic benefit (5.1.3).

• Age ≥18 years

• Eastern Cooperative Oncology Group (ECOG) performance status between 0-2

• Expected life expectancy of at least 12 months per the investigator.

• The following laboratory or clinical values obtained ≤ 42 days prior to enrollment:

  • Absolute neutrophil count ≥1000/µL (G-CSF support is allowed) unless documented bone marrow involvement of CLL

  • Platelets of ≥50K/µL unless documented bone marrow involvement of CLL

  • Creatinine Clearance (CrCl) ≥45 mL/minute as measured by a 24 hour urine collection or calculated by the Cockcroft-Gault Formula

  • Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN) unless due to Gilbert's disease. For those patients with previous history of Gilbert's disease, a direct bilirubin should be performed and must be <1.5mg/dL.

  • SGOT (AST)/SGPT (ALT) ≤3.0 x the institutional ULN

  • Time from the start of the Q wave to the end of the T wave (QT) corrected for heart rate by Fridericia's cube root formula (QTcF) ≤470 msec

    • For patients with prolonged AT interval due to bundle branch block, a "corrected value" ≤470 msec and confirmation by cardiologist that patient is asymptomatic and that no other cardiac conduction or cardiac abnormality is present would pose any safety issues for the patient.
    • Recommended correction of QT for patients with bundle branch block are as follows: Patient's Q wave R wave and S wave complex (QRS) is 160 msec, and the measured QT is 510 msec. As the normal QRS is ~120 msec, subtract 120 msec from the measured QRS of the patient (160-120 = 40 msec) and then subtract this result from the measured QT (510-40=470 msec).

  • Pulse oximetry reading of ≥90% on room air

• Able to adhere to study visit schedule and other protocol requirements

• Patients must be able to swallow capsules

• Patients must be able to receive xanthine oxidase inhibitor and/or rasburicase for tumor lysis syndrome prophylaxis.

• Patients with a history of hepatitis B (surface antigen or core antibody-positive and polymerase chain reaction (PCR) positive) must take lamivudine or equivalent drug during study therapy and for one year after completion of all therapy. Patients on IVIG who are core antibody-positive but PCR negative are not mandated to take prophylaxis.

• Patients who are HIV (human immunodeficiency virus) positive are eligible under the following circumstances:

  • Undetectable HIV viral load (laboratory value obtained within the last 6 months prior to enrollment)
  • CD4 count ≥200 (laboratory value obtained within the last 6 months prior to enrollment)
  • Actively taking antiretroviral therapy (ART)
  • Current ART therapy cannot have significant interactions with RP-3500 or Olaparib (Refer to Appendix 5). If current medications do interact, patients should receive alternative ART.

• Recovery to baseline or ≤ Grade 1 CTCAE v5.0 from toxicities related to any prior cancer therapy, unless considered clinically not significant by the treating investigator.

• Female patients capable of reproduction or males who have partners capable of reproduction must agree to the use of an effective contraceptive method during the course of the study and for 6 months following the completion of their last treatment.

• Females of childbearing potential must have a negative serum β-Hcg pregnancy test result within 3 days of the first study dose. Female patients who are surgically sterilized or who are >45 years old and have not experienced menses for >2 years may have β-Hcg pregnancy test waived.

Exclusion Criteria:

• Patients who are currently receiving any other investigational drug. Patients who are or have received therapies for the prevention, treatment or management of Corona Virus 19 (COVID-19) under the Food and Drug Administration (FDA) emergency use authorization are allowed to enroll.

• Patients who have received:

  • Radiation or chemotherapy ≤2 weeks prior to registration.

  • Immunotherapy or targeted therapy ≤2 weeks prior to registration.

    ---Patients currently on BCR pathway antagonists (i.e. BTK and PI3K inhibitors, etc) require a 2 day wash out period prior to starting combination therapy with RP-3500 and olaparib as these subjects progress quickly after treatment discontinuation.

  • Strong CYP3A inhibitors or inducers, p-glycoprotein inhibitors, or BCRP inhibitors within five half-lives or 14 days of registration, whichever is shorter (See Appendix 5).

• Prior ATR inhibitor use, but prior PARP inhibitor use for any reason is allowed on study.

• Major surgery 4 weeks prior to C1D1 or who have not fully recovered from major surgery.

• Evidence of active Richter's Transformation

• Disease states requiring steroids (e.g. adrenal insufficiency, autoimmune conditions) are allowed as long as the steroid dose is ≤10mg of prednisone or equivalent dose of another steroid. Steroids premedications to prevent iodine contrast allergy for CT scans are allowed.

• Patients who have undergone autologous stem cell transplant ≤4 weeks or allogeneic stem cell transplant ≤12 weeks prior to cycle 1 day 1 or have active graft-versus-host disease are excluded.

• Patients who have active, clinically significant hepatic impairment (≥ moderate hepatic impairment according to the NCI/Child-Pugh classification)

• Prior history of another malignancy except for the following:

  • Patients with current history of basal or squamous skin carcinoma, cervical carcinoma in situ, localized breast cancer requiring hormonal therapy, or localized prostate cancer (Gleason score <6) are allowed.
  • Previously treated malignancies (with chemotherapy, radiation, and/or surgery) currently deemed to have been in complete remission for at least 24 months.

• Patients with active known central nervous system (CNS) involvement of CLL. Patients with a history of CNS CLL now in remission are eligible for the trial.

• Patients with uncontrolled concurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, extensive bilateral interstitial lung disease, unstable angina pectoris, or psychiatric illness/social situations that would limit compliance with study requirements.

  --Patients with a history of pneumonitis or pulmonary disease that could predispose them to development of Interstitial lung disease (ILD) and/or underlying respiratory conditions should be excluded.

• Known prior severe hypersensitivity to RP-3500, olaparib, or any component in its formulations (NCI CTCAE v5.0 Grade ≥ 3).

• Female patients who are pregnant or actively breast feeding

• Patients with conditions significantly affecting gastrointestinal function including, but not limited to:

  • Significant resection of the stomach or small bowel
  • Symptomatic inflammatory bowel disease
  • Partial or complete bowel obstruction