Which Statements Are True?

Statements a, b, c, and e are true; statement d is false.

Statement-by-Statement Analysis

Lenalidomide combined with dexamethasone is an established treatment for relapsed or refractory multiple myeloma, demonstrating 58-59% response rates in phase III trials 1.
This regimen provides a treatment option alongside bortezomib and thalidomide-based regimens for relapsed/refractory disease 1.
The standard dosing is lenalidomide 25 mg/day orally in combination with dexamethasone, continued until disease progression 1.

Cytarabine is a cornerstone agent in acute myeloid leukemia (AML) treatment, used in multiple regimens 2.
The NCCN guidelines specifically include cytarabine-based induction regimens such as ATRA + cytarabine (AIDA regimen) for acute promyelocytic leukemia 2.
For higher-risk MDS and AML, combinations of cytarabine with idarubicin, fludarabine, or topotecan are standard regimens with equivalent efficacy 2.
Low-dose cytarabine (20 mg/m²/day for 14-21 days every 4 weeks) is also used as an alternative treatment option in certain MDS patients 2.

Lenalidomide is FDA-approved for low-risk MDS with deletion 5q cytogenetic abnormality 1.
The ESMO guidelines recommend lenalidomide for anemia in lower-risk MDS with del(5q), achieving 60-65% response rates with median RBC transfusion independence of 2-2.5 years 2.
The recommended starting dose is 10 mg/day orally for 3 weeks every 4 weeks 2.
Cytogenetic responses occur in 50-75% of patients (including 30-45% complete cytogenetic responses) 2.
Lenalidomide should be the drug of choice for patients with low and intermediate-1 risk MDS with chromosome 5q31 deletion 1.
In the EU, lenalidomide is approved specifically for lower-risk MDS with del(5q) and RBC transfusion dependence after failure or ineligibility to erythropoietin-stimulating agents 2.

This statement is completely incorrect. Vitamin B12 is used to treat B12-deficiency megaloblastic anemia, not immune thrombocytopenic purpura (ITP) 2.
ITP is an autoimmune disorder causing platelet destruction and requires treatments such as corticosteroids, intravenous immunoglobulin, or thrombopoietin receptor agonists—not vitamin supplementation.
Vitamin B12 deficiency causes macrocytic anemia with low reticulocytes, not thrombocytopenia 2.

The FDA label explicitly states that folic acid is effective in the treatment of megaloblastic anemias due to folic acid deficiency 3.
This includes megaloblastic anemias seen in tropical or nontropical sprue and anemias of nutritional origin, pregnancy, infancy, or childhood 3.
Folate deficiency is characterized by macrocytic anemia with normal or low reticulocytes and occurs with increased folate requirements (pregnancy, hemolysis, chronic myeloid leukemia) 2.

For lenalidomide in MDS:

Close monitoring for grade 3-4 neutropenia and thrombocytopenia is essential, occurring in ~60% of patients during the first weeks of treatment 2.
TP53 mutations (found in ~20% of del(5q) MDS) confer resistance to lenalidomide and higher risk of AML progression, requiring intensified surveillance 2.
Dose reduction is frequently required due to myelosuppression 1.

For cytarabine in acute leukemia:

AML-like intensive chemotherapy with cytarabine has limited indication in higher-risk MDS patients, particularly those with unfavorable karyotype who show few complete remissions and shorter CR duration 2.
Low-dose cytarabine was found significantly inferior to azacitidine in terms of response and survival in a randomized phase III study 2.