Recurred. How does this change my treatment choices, and are new targeted therapies using biomarkers (BCR-ABL, FLT3)...

I'm sorry to hear that your leukemia has recurred. Relapsed or recurrent leukemia often requires adjustments to the treatment plan.

For acute lymphoblastic leukemia (ALL), the treatment approach upon relapse depends on several factors outlined in the NCCN Guidelines:

Timing of Relapse:

• If the relapse occurs within 6 months of initial treatment, it is considered an early relapse and has a worse prognosis. More aggressive therapy is typically recommended.
• If relapse occurs after 6 months, it is considered a late relapse and may allow for more standard re-induction regimens.

Site of Relapse:

• Bone marrow relapse is most common and may be treated with chemotherapy +/- stem cell transplant.
• Isolated extramedullary (e.g. CNS) relapse may require radiation and/or intensive systemic therapy.

Prior Therapy Responses:

• Patients who achieved a longer initial remission may be re-treated with their initial successful regimen.
• Those with chemotherapy-resistant disease may be candidates for targeted therapies or more intensive regimens.

Regarding targeted therapies, the NCCN Guidelines mention several biomarker-driven options for relapsed/refractory ALL (pages 39-42):

• Blinatumomab (anti-CD19) for Philadelphia chromosome-negative disease
• Inotuzumab ozogamicin (anti-CD22) for Philadelphia chromosome-positive or negative disease
• Ponatinib or other TKIs if BCR-ABL positive
• Gilteritinib if FLT3 mutation positive

However, your specific eligibility would depend on your leukemia subtype, genomic markers, prior responses, and other clinical factors. Discussing the risks and benefits of various approaches with your oncologist is recommended.