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Chronic Lymphocytic LeukemiaPhase 2BOSSNCT06839872

A Study to Investigate the Sequencing Strategy of Pirtobrutinib After Disease Progression on First-line Acalabrutinib Treatment for Adult Participants With Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

A Phase 2 study testing Pirtobrutinib and Acalabrutinib in people with Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma, run by AstraZeneca.

Withdrawn

Withdrawn. The study stopped before anyone enrolled.

Official record
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Trial summary

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

Who is it for?
Ages 18 to 110 years
What is being tested?
Pirtobrutinib and Acalabrutinib
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
0 participants
Where
No sites listed yet
Study dates
30 Jun 2025to 29 Jul 2030
Phase
Phase 2
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 110 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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.

Who cannot join

  • 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.
Show all 15Show fewer
  • 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.

About this study

Official title: BOSS: BTK Inhibitor Optimal Sequencing Study Phase II Open-label Single Arm Trial of Pirtobrutinib in Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma After First-line Acalabrutinib Progression

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

Read the detailed description

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.
Being tested
Pirtobrutinib, Acalabrutinib
Keywords
Chronic Lymphocytic Leukemia, Small Lymphocytic Lymphoma
Medical subject headings
Leukemia, Lymphocytic, Chronic, B-Cell

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PirtobrutinibDrug

    Also called JAYPIRCA

    Patients will receive pirtobrutinib orally with dosing schedule as prescribed

  • AcalabrutinibDrug

    Also called CALQUENCE®

    Patients will receive acalabrutinib orally with dosing schedule as prescribed.

Study groups in NCT06839872
Study groupRoleWhat they receive
Pirtobrutinib and AcalabrutinibExperimentalParticipants will receive dose A of pirtobrutinib starting Cycle 1 Day 1 for up to 24 cycles or until disease progression, unacceptable toxicity, death, or withdrawal of consent. If they progress on pirtobrutinib, a subset will receive dose B of acalabrutinib starting Cycle 1 Day 1 for up to 12 cycles or until disease progression, death, intolerance, unacceptable toxicity, or withdrawal of consent. Those benefiting from treatment will enter the Disease Follow-up period, continuing with pirtobrutinib or acalabrutinib until disease progression, unacceptable toxicity, death, or withdrawal of consent. After 36 months from starting pirtobrutinib, participants can continue receiving treatment off-trial if beneficial, in consultation with their physician.
Receives: Drug: Pirtobrutinib; Drug: Acalabrutinib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Objective Response Rate (ORR) in participants with CLL/SLL.

    ORR is defined as the proportion of participants who achieve best response of CR, CRi, nPR, or PR per the iwCLL Criteria as assessed by the investigator.

    Measured: ORR will be assessed after 12 cycles (each cycle lasts 28 days) of pirtobrutinib.

Secondary outcomes (4)

  1. Investigator assessed ORR in participants with CLL/SLL.

    ORR is defined as the proportion of participants who achieve best response of CR, CRi, nPR, or PR per the iwCLL Criteria as assessed by the investigator.

    Measured: ORR will be assessed after 24 cycles (each cycle is 28 days) of pirtobrutinib and at 3 years from Cycle 1: Day 1 of pirtobrutinib.

  2. Progression free Survival (PFS) in participants with CLL/SLL.

    PFS is defined as time from date of the first dose of pirtobrutinib until disease progression per the iwCLL Criteria as assessed by the investigator, or death due to any cause in the absence of disease progression.

    Measured: PFS will be assessed at 24 months of pirtobrutinib treatment.

  3. Safety and tolerability of pirtobrutinib in CLL/SLL following disease progression on first-line acalabrutinib in participants with CLL/SLL.

    Safety and tolerability will be evaluated as the number of participants with Adverse Events (AEs), Serious Adverse Events (SAEs), and AE leading to treatment discontinuation.

    Measured: Safety and tolerability will be evaluated at every visit starting from pirtobrutinib treatment through the study completion (for 3 years)

  4. Safety of acalabrutinib retreatment following disease progression on pirtobrutinib in participants with CLL/SLL.

    Safety will be evaluated as the number of participants with Adverse Events (AEs), Serious Adverse Events (SAEs), and AE leading to treatment discontinuation.

    Measured: Safety will be evaluated at every visit starting from acalabrutinib treatment through the study completion (for 3 years)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted21 Feb 2025
  2. Study start30 Jun 2025 (estimated)
  3. Primary completion28 Jul 2028 (estimated)
  4. Study completion29 Jul 2030 (estimated)

Why it stopped: AstraZeneca has made the decision to cancel the trial.

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
0 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06839872
Sponsor's protocol ID
D8220R00065
Acronym
BOSS
Status last verified
Jun 2025
First submitted
21 Jan 2025
Last updated
5 Jun 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: 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

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Pirtobrutinib and Acalabrutinib in people with Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma, run by AstraZeneca.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 7 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: withdrawn, as of the sponsor's last update on 5 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study was withdrawn before enrolling participants, so there are no results.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Objective Response Rate (ORR) in participants with CLL/SLL. (time frame: ORR will be assessed after 12 cycles (each cycle lasts 28 days) of pirtobrutinib.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06839872.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jun 2025; AzTrials last refreshed its copy on 8 Nov 2026.

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