Approved treatment — U.S. FDA (2026-10-02), previously untreated CLL/SLL without 17p deletion Japan — pirtobrutinib approved for mantle cell lymphoma (2024-06); check CLL scope
A new option for first-line CLL treatment: on October 2, 2026, the U.S. FDA approved the once-daily oral targeted drug pirtobrutinib (Jaypirca) for adults starting treatment for chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). In the phase 3 BRUIN CLL-313 trial, 93.4% of patients were free of disease progression at two years, compared with 70.7% on standard chemoimmunotherapy (bendamustine plus rituximab).
What was approved: an oral BTK inhibitor as first treatment
Chronic lymphocytic leukemia is a slow-growing blood cancer of B cells, a type of lymphocyte. When the same disease appears mainly in the lymph nodes it is called small lymphocytic lymphoma, and it is treated the same way. It is the most common adult leukemia in Western countries; it is less common in Asia, but patients are diagnosed in Japan as well.
Modern CLL treatment centers on BTK inhibitors. BTK (Bruton's tyrosine kinase) is a signaling protein that B cells need to survive and grow, so blocking it slows the cancer. The existing drugs ibrutinib, acalabrutinib and zanubrutinib are “covalent” inhibitors that bind tightly to one site on BTK (C481). Pirtobrutinib binds differently: it is a non-covalent BTK inhibitor and the first of this class approved by the FDA. It can therefore act even when a C481 mutation has made earlier drugs stop working.
In the U.S., pirtobrutinib was first used in December 2023 for CLL that relapsed after a covalent BTK inhibitor (converted to full approval in December 2025). This approval extends its use to patients starting treatment for the first time. The dose is 200 mg once daily, with or without food, continued until the disease progresses or side effects become unacceptable.
Who is eligible: first-line patients without 17p deletion
According to the FDA wording, the approval covers adults who meet all of the following:
- Diagnosed with chronic lymphocytic leukemia or small lymphocytic lymphoma
- No previous treatment for this disease
- No known 17p deletion (del(17p)) on chromosome testing
17p deletion is the loss of the chromosome region carrying the TP53 gene; chemotherapy often works poorly in this setting, so these patients were not part of the comparison. Genetic and chromosome tests such as FISH are therefore checked before treatment begins. The trial balanced patients by IGHV mutation status (a prognostic marker), and the benefit pointed in the same direction regardless of IGHV status. U.S. NCCN guidelines also list pirtobrutinib as an option for older patients with heart conditions.
BRUIN CLL-313 results: 80% lower risk of progression or death
The approval rests on the international randomized phase 3 trial BRUIN CLL-313 (NCT05023980). A total of 282 untreated patients were assigned to pirtobrutinib (141) or bendamustine plus rituximab for six cycles (141), with a median follow-up of 28 months. The results were published in the Journal of Clinical Oncology (Jurczak W et al., online December 2025).
| Measure | Pirtobrutinib | Bendamustine + rituximab |
|---|---|---|
| 2-year progression-free survival | 93.4% | 70.7% |
| Median progression-free survival | Not reached | 33.5 months |
| Hazard ratio (progression or death) | 0.20 (95% CI 0.11–0.37) — 80% risk reduction | |
| Overall response rate | 94% | 81% |
| Grade 3 or higher adverse events | 40.0% | 67.4% |
| Dose reduction due to side effects | 3.6% | 31.1% |
Sources: Eli Lilly release (2026-10-02), ONS summary of the FDA approval (2026-10-05), The ASCO Post, February 2026 (JCO paper). Progression-free survival was assessed by an independent review committee.
“Progression-free survival” is the time patients live without the disease growing or death. In the pirtobrutinib group, more than half of patients remained progression-free during follow-up, so the median has not yet been reached. Overall survival is still early, but deaths were reported in 3 patients (2.1%) on pirtobrutinib versus 10 (7.1%) in the comparison group.
In the companion BRUIN CLL-314 trial (662 patients), pirtobrutinib was compared head to head with the established BTK inhibitor ibrutinib. The overall response rate was 87.0% versus 78.5%, meeting the non-inferiority goal, and atrial fibrillation or flutter was less frequent (2.4% versus 13.5%).
Side effects and management: infection prevention and regular blood tests
The most common side effects in BRUIN CLL-313 were upper respiratory tract infection (27%), rash (22%) and COVID-19 infection (21%). On blood tests, low neutrophil count (48%) was the most frequent finding. Serious adverse reactions occurred in 28%, most often pneumonia (5%). Only 4.3% stopped the drug because of side effects (15.4% in the comparison group), and atrial fibrillation or flutter, a known concern with BTK inhibitors, occurred in 1.4% (1.5% in the comparison group). Minor bruising or bleeding was reported in 25.7%.
The FDA label lists infections, bleeding, low blood counts, heart rhythm problems, second cancers (mainly skin cancer), liver toxicity and harm to an unborn baby as warnings. In practice, regular blood tests check blood counts and liver function, patients report fever or other signs of infection promptly, and whether to pause the drug before surgery or procedures is decided with the care team. Some medicines (strong CYP3A inhibitors or inducers) change drug levels, so all current medications should be shared with the doctor.
Where it is available: approved in the U.S., recommended in Europe
- United States: approved by the FDA on October 2, 2026 as first-line treatment for CLL/SLL without 17p deletion (approved treatment).
- Europe: on June 26, 2026, the European Medicines Agency's CHMP issued a positive opinion recommending approval for CLL across all lines of therapy, regardless of prior BTK inhibitor use. The final decision is made by the European Commission.
- Japan: pirtobrutinib (also sold as Jaypirca) was approved in June 2024 for relapsed or refractory mantle cell lymphoma resistant or intolerant to other BTK inhibitors and is in use. For CLL, check the current Japanese approval scope in announcements from Eli Lilly Japan or PMDA.
Approval scope and insurance coverage differ by country, so if you are considering treatment abroad, check that country's approval and costs first. Guidance on reading Japanese medical information is available in Other Japan medical information.
What to check and questions for your doctor
- Do I need to start treatment now, or is watchful waiting appropriate?
- What are my 17p deletion, TP53 mutation and IGHV test results?
- Is a continuous BTK inhibitor or a fixed-duration treatment (such as a venetoclax combination) better for me?
- I have heart disease or take blood thinners — which BTK inhibitor suits me best?
- How often will I need blood tests, and how should I prevent infections (vaccines, etc.)?
Frequently asked questions
How is pirtobrutinib different from other BTK inhibitors?
Drugs such as ibrutinib bind covalently to the C481 site of BTK, while pirtobrutinib binds non-covalently. It can therefore act even when a C481 mutation has made earlier drugs stop working, and with this approval it can also be used as a first treatment.
How effective was it as first-line CLL treatment?
In BRUIN CLL-313, the 2-year progression-free survival rate was 93.4% versus 70.7% with bendamustine plus rituximab, and the risk of progression or death fell by 80%. The overall response rate was 94%.
What are the side effects of pirtobrutinib?
Upper respiratory infections, rash, COVID-19 infection and low neutrophil counts were common. Only 4.3% stopped treatment because of side effects, and atrial fibrillation occurred in 1.4%, similar to the comparison group. Regular blood tests and attention to signs of infection help manage them.
Can pirtobrutinib be prescribed in Japan?
In Japan it was approved in June 2024 for relapsed or refractory mantle cell lymphoma and is prescribed for that use. For first-line CLL, check the latest announcements from Eli Lilly Japan and PMDA for the approval scope as of the source check date (2026-10-23).
Related: HER2 breast cancer maintenance: FDA approves tucatinib · CAR-NK vs CAR-T · All articles by cancer type
Sources
- Eli Lilly and Company — FDA approves expanded indication for Lilly's Jaypirca (pirtobrutinib) as first-line treatment for CLL/SLL (2026-10-02)
investor.lilly.com
Checked: 2026-10-23 - Oncology Nursing Society (ONS) Voice — FDA approves pirtobrutinib for previously untreated chronic lymphocytic leukemia or small lymphocytic lymphoma (2026-10-05)
ons.org
Checked: 2026-10-23 - Jurczak W, Kwiatek M, Czyz J, et al. BRUIN CLL-313: randomized phase III trial of pirtobrutinib versus bendamustine plus rituximab in untreated CLL/SLL. J Clin Oncol 2025 — The ASCO Post summary (2026-02)
ascopost.com
Checked: 2026-10-23 - ClinicalTrials.gov — NCT05023980: Pirtobrutinib versus bendamustine plus rituximab in untreated CLL/SLL (BRUIN CLL-313)
clinicaltrials.gov/study/NCT05023980
Checked: 2026-10-23 - OncLive — CHMP recommends pirtobrutinib for EU approval in CLL across all lines of therapy (2026-06-26)
onclive.com
Checked: 2026-10-23 - Eli Lilly Japan — Japan approval of pirtobrutinib (Jaypirca) for relapsed or refractory mantle cell lymphoma (2024-06-24, Japanese-language source)
mediaroom.lilly.com
Checked: 2026-10-23
Written by the FTH editorial team. Sources checked 2026-10-23 · Medical review: not applicable
This article is general information based on public sources and does not replace diagnosis or treatment. Please discuss treatment decisions with your medical team.
