Isatuximab subcutaneous injection is a cytolytic antibody targeting CD38, used in combination therapy for multiple myeloma.

I. Indications

1. Relapsed or Refractory Multiple Myeloma

(1) Isatuximab subcutaneous injection in combination with pomalidomide and dexamethasone is indicated for adult patients who have received at least one prior line of therapy, including lenalidomide and a proteasome inhibitor.

(2) Isatuximab subcutaneous injection in combination with carfilzomib and dexamethasone is indicated for adult patients with relapsed or refractory multiple myeloma who have received 1 to 3 prior lines of therapy.

2. Newly Diagnosed Multiple Myeloma

This product, in combination with bortezomib, lenalidomide, and dexamethasone, is indicated for adult patients with newly diagnosed multiple myeloma who are not eligible for autologous stem cell transplantation.

II. Dosage and Administration

1. Route of Administration and Dose

(1) This product is for subcutaneous injection into the abdomen only. The recommended fixed dose is 1,400 mg (i.e., 10 mL solution). Do not administer intravenously.

(2) Each injection must be administered by a healthcare professional, using either the CirCLIQ® infusion system or a manual syringe (with an infusion device).

2. Dosing Frequency in Combination Regimens

(1) In combination with pomalidomide/dexamethasone or carfilzomib/dexamethasone: Cycle 1 (28 days) – once weekly (Days 1, 8, 15, 22); from Cycle 2 onward – once every 2 weeks (Days 1, 15).

(2) In combination with bortezomib/lenalidomide/dexamethasone: Cycle 1 – once weekly; Cycles 2 to 12 – once every 2 weeks; from Cycle 13 onward – once every 4 weeks (Day 1).

(3) Treatment continues until disease progression or unacceptable toxicity.

3. Management of Missed Dose

If a planned dose is missed, administer it as soon as possible and adjust subsequent dosing intervals accordingly to maintain the original treatment cycle duration.

III. Pre‑administration Preparation and Administration Instructions

1. Premedication Requirements

(1) Within 15–60 minutes before each injection, administer dexamethasone (dose adjusted according to the combination regimen and age), a leukotriene receptor antagonist (only during Cycle 1), acetaminophen, and an antihistamine (e.g., diphenhydramine) to reduce the risk of systemic reactions.

(2) If no reaction occurs during Cycle 1, premedication may be omitted in subsequent cycles at the discretion of the physician.

2. Preparation and Storage of the Solution

(1) After removal from refrigeration, allow the vial to stand at 18–28°C room temperature for approximately 20 minutes. Do not heat or shake.

(2) Once the vial is punctured, the injection must be completed within 4 hours; any unused solution should be discarded.

(3) The solution should be clear to slightly opalescent, colorless to slightly yellow, with a small amount of translucent particles considered normal. Do not use if the solution is cloudy or discolored.

3. Injection Site and Procedure

(1) Administer into the abdomen only. Rotate injection sites each time (at least 2.5 cm from the previous injection point), avoiding the 2‑inch area around the navel and skin with lesions, redness, scarring, or excessive hair.

(2) For manual injection, insert the needle at a 45° angle quickly, and push the solution over approximately 6 minutes. If pain occurs, pause or slow the injection rate; if necessary, switch to the opposite side of the abdomen to complete the remaining dose.