AstraZeneca has made the decision to cancel the trial.

To assess the efficacy and safety of pirtobrutinib in participants with CLL/SLL who have progressed on first-line treatment with acalabrutinib.

The purpose of this study is to assess the efficacy and safety of pirtobrutinib in participants with CLL/SLL who have progressed on first-line treatment with acalabrutinib. A subset of participants who have disease progression on pirtobrutinib will be retreated with acalabrutinib to assess whether relapsed CLL can be re-sensitized to a covalent irreversible BTK inhibitor such as acalabrutinib, and thereby, remain on treatment within the BTK inhibitor class rather than transition into another CLL/SLL treatment.

• The study duration for each participant will be up to 3 years in total.
• For participants who receive pirtobrutinib alone, the visit frequency will be approximately every month for the first 6 months. After that, the visit frequency will be reduced to one visit approximately every 3 months for the subsequent 12 months. The final part of the Treatment Phase has 2 visits in the space of 6 months. There is one visit to the site after the Treatment Phase.
• Participants who have disease progression on pirtobrutinib and go on to receive acalabrutinib retreatment will visit the site approximately once every month for the first 6 months. After that, the visit frequency will be reduced to 2 visits in the space of 6 months. There is one visit to the site after the Treatment Phase.

Inclusion Criteria:

• Participant must be ≥ 18 at the time of signing the informed consent.
• Participants must have received acalabrutinib monotherapy as first-line treatment for CLL/SLL, have progressed per the iwCLL Criteria (Hallek et al 2018) and be eligible for second-line treatment by the same criteria.
• ECOG performance status of 0, 1, or 2.
• Adequate organ and BM function.
• Adequate coagulation, defined as aPTT or PTT and PT or INR not greater than 1.5 × ULN.
• Participants have a clearly defined, documented and accessible start date of their first line acalabrutinib monotherapy for CLL/SLL.
• Participants are eligible for the acalabrutinib retreatment phase only if they have progressed on pirtobrutinib monotherapy per iwCLL Criteria.

Exclusion Criteria:

• Major surgical procedure within 30 days before and not recovered adequately the first dose of study drug.
• Participants who experienced a major bleeding event or Grade ≥ 3 arrhythmia on prior treatment with a BTK inhibitor.
• History of bleeding diathesis (eg, hemophilia, von Willebrand disease).
• History of stroke or intracranial hemorrhage within 6 months before first dose of study drug.
• Significant cardiovascular disease.
• History of PML.
• Any active significant infection.
• HIV positive
• Active HBV or HCV infection.
• Active CNS involvement by lymphoma, leptomeningeal disease, or spinal cord compression.
• Active auto-immune cytopenia.
• History of prior or current malignancy.
• Requires or receiving therapeutic anticoagulation with warfarin or equivalent vitamin K antagonists.
• Received a live virus vaccination within 28 days of first dose of study drug.
• Requires treatment with a strong CYP3A inhibitor or inducer. The use of strong CYP3A inhibitors within 1 week or strong CYP3A inducers within 3 weeks of the first dose of study drug is prohibited.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool. Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.