Imetelstat, as a novel targeted agent, has no absolute contraindications, but special populations require extra caution.

I. Contraindications and General Warnings

1. No Absolute Contraindications

(1) The prescribing information for imetelstat does not list any absolute contraindications, meaning there is no situation in which the drug is completely prohibited.

(2) However, this does not imply that it can be used indiscriminately. Strict adherence to indication screening is still required, and decisions should be made cautiously after a thorough assessment of the patient's overall condition.

2. Exclusion of Pregnancy Status

Although there are no absolute contraindications, for pregnant women, animal studies suggest that the drug may cause harm to the fetus. Therefore, pregnancy status must be confirmed before use, and the benefits and risks must be evaluated before deciding on treatment.

II. Considerations for Special Populations

1. Pregnant and Breastfeeding Women

(1) Pregnancy: Animal studies have shown that this product may cause embryonic death. Pregnant women should be fully informed of the potential risks. Women of childbearing age should undergo pregnancy testing before treatment.

(2) Breastfeeding: There are currently no data on whether the drug is excreted in human milk. To avoid adverse effects on infants, breastfeeding is not recommended during treatment and for one week after the last dose.

2. Children and Adolescents

The safety and efficacy of this product in pediatric patients have not been established through research; therefore, it is not recommended for use in individuals under 18 years of age.

3. Elderly Patients

(1) In clinical studies, patients aged 65 years and older accounted for a significant proportion, and no differences in safety or efficacy were observed compared with younger adults.

(2) No specific dose adjustment is required based on age.

4. Patients with Impaired Hepatic or Renal Function

(1) No significant changes in pharmacokinetics were observed in patients with mild to moderate hepatic impairment or mild to moderate renal impairment.

(2) Data are insufficient for patients with severe renal impairment (creatinine clearance below 30 mL/min), end-stage renal disease, or severe hepatic impairment. The risk of drug use is not clearly defined, and careful evaluation is required.

III. Fertility and Contraceptive Recommendations

1. Contraceptive Requirements for Women of Childbearing Age

(1) Animal studies suggest that this product may cause harm to the fetus. Therefore, women of childbearing potential must use effective contraception during treatment and for one week after the last dose.

(2) If pregnancy is suspected during treatment, the physician should be informed immediately.

2. Potential Effects on Fertility

(1) In animal studies, high doses were observed to affect the endometrium in females, but this was reversible after drug discontinuation.

(2) Although human fertility studies have not been conducted, patients with fertility needs should fully discuss the potential impact with their physician before treatment.

3. Considerations for Male Fertility

Currently, there are no clear data indicating an effect of this product on male fertility. However, men with reproductive plans are advised to consult a specialist before treatment to assess potential risks.

Note: Specific treatment regimens and individualized adjustments for special populations must follow the comprehensive evaluation and guidance of the attending physician.