7+3 (chemotherapy)


"7+3" in the context of chemotherapy is an acronym for a chemotherapy regimen that is most often used today as first-line induction therapy in acute myelogenous leukemia, excluding the acute promyelocytic leukemia form, which is better treated with ATRA and/or arsenic trioxide and requires less chemotherapy.
The name "7+3" comes from the duration of chemotherapy course, which consists of 7 days of standard-dose cytarabine, and 3 days of an anthracycline antibiotic or an anthracenedione, most often daunorubicin.

Dosing regimen

Standard-dose cytarabine plus daunorubicin (DA or DAC chemotherapy)

DrugDoseModeDays
Cytarabine100–200 mg/m2IV continuous infusion over 24 hoursDays 1-7
Daunorubicin 60–90 mg/m2IV bolusDays 1-3

Standard-dose cytarabine plus idarubicin (IA or IAC chemotherapy)

DrugDoseModeDays
Cytarabine100–200 mg/m2IV continuous infusion over 24 hoursDays 1-7
Idarubicin12 mg/m2IV bolusDays 1-3

Standard-dose cytarabine plus mitoxantrone (MA or MAC chemotherapy)

DrugDoseModeDays
Cytarabine100–200 mg/m2IV continuous infusion over 24 hoursDays 1-7
Mitoxantrone7 mg/m2IV infusionDays 1, 3 and 5

Intensified versions

There were attempts to intensify the "7+3" regimen in order to try to improve its efficacy. Attempts were made to prolong the course.
On the other hand, there were attempts to minimize the toxicity of the regimen by reducing the dose or the duration of the course. But this proved to compromise the efficacy of the regimen.
The addition of vinca alkaloids to the "7+3" regimen, which addition was quite popular in AML in old times proved to be harmful in AML, lowering the chance of the patient to get remission. This is because vinca alkaloids are rapidly deactivated in myeloid cells by their enzyme myeloperoxidase. So the vinca alkaloids do much more damage to the lymphoid cell lines than to the myeloid cell lines. Moreover, vinca alkaloids in the context of AML cause AML cells to undergo a cell cycle arrest in the phase that renders those cells less sensitive to cytarabine and anthracyclines.
Addition of glucocorticoids or methotrexate or alkylating drugs to the "7+3" regimen is also of no benefit in AML.
The addition of etoposide to the standard "7+3" regimen is sometimes of benefit in poor-risk patients. It gave rise to the so-called ADE induction regimen in AML. The ADE induction is still sometimes used, especially in poor-risk AML patients.
The addition of 6-thioguanine gave rise to the DAT regimen, and the addition of 6-mercaptopurine gave rise to the DAM regimen.