January 4, 2022
Kristi Rosa

The FDA has granted a rare pediatric disease designation to IMX-110 for the treatment of rhabdomyosarcoma.

The FDA has granted a rare pediatric disease designation (RPDD) to IMX-110 for the treatment of rhabdomyosarcoma, according to an announcement from Immix Biopharma, Inc., the drug developer.1

The novel product is a Tissue-Specific Therapeutic that was built on the clinical-stage biopharmaceutical company’s TME Normalization Technology, which allows for the agent to circulate in the bloodstream, subsequently exit through porous tumor blood vessels, and accumulate in the tumor microenvironment.2

Then, IMX-110 simultaneously attacks the following 3 components of the microenvironment: cancer-associated fibroblasts, tumor-associated macrophages/immune cells, and the cancer itself; this severs the lifelines between the tumor and its metabolic and structural support. The product’s technology causes tumor apoptosis.

RPDD is only given to products developed to treat serious and life-threatening diseases that primarily affect children aged up to 18 years of age, and impact fewer than 200,000 individuals in the United States. If a new drug application for the agent is approved in the country, the company may be eligible to receive a priority review voucher from the agency, which can then be redeemed to obtain priority review for any subsequent marketing application.

“We are pleased by the FDA’s acknowledgement of the urgent need for a safe and effective treatment for children with this devastating disease,” Ilya Rachman, MD, PhD, chief executive officer of Immix Biopharma, Inc., stated in a press release.

Clinical findings across several soft tissue sarcoma subtypes in several heavily pretreated patients indicated that the investigational agent resulted in a median progression-free survival (PFS) of 4.0 months.3 Tumor shrinkage was observed in 75% of these patients. Moreover, no treatment-related serious adverse effects (AEs), nor dose interruptions due to toxicity, were reported.

“We are encouraged by our phase 1b/2a clinical data in soft tissue sarcoma,” Rachman added. “IMX-110 is a tissue-specific therapeutic that simultaneously attacks all 3 components of the tumor microenvironment, severing the critical lifelines between the tumor and its metabolic and structural support. We believe our SMARxT platform generating Tissue-Specific Therapeutics represents a distinct alternative to the traditional ‘single target, single mutation’ development model.”

The safety, tolerability, and pharmacokinetics of IMX-110 in patients with advanced solid tumors is currently under investigation as part of an open-label, multicenter, dose-escalation/-expansion phase 1/2 trial (NCT033892340).4

To be eligible for enrollment, patients need to be at least 18 years of age, have a confirmed advanced solid tumor as per histology and have progressed or are refractory or intolerant to standard treatment. Patients need to have an ECOG performance status ranging from 0 to 2, a life expectancy of at least 3 months, acceptable cardiac function, and must meet certain laboratory requirements.

If patients have a history of severe allergic reactions to any unknown allergens or any components of the study drug formulation, received chemotherapy within 14 days of dosing, immunotherapy within 28 days of dosing, or a biologic of hormonal therapy within 28 days of dosing, they will be excluded.

Other exclusion criteria include having participated in any other drug study up to 4 weeks before study drug administration, requiring surgery or benefit from other anticancer agents, a history of and/or risk factors for ischemic heart disease, no recovery of toxicities from prior treatment, and being positive for human immunodeficiency virus, hepatitis B virus, or hepatitis C virus.

The primary outcome measures are examining the number of treatment-related AEs and identifying the maximum tolerated dose of IMX-110 and the recommended phase 2 dose of the agent. Secondary outcome measures include evaluating plasma concentrations of IMX-110, response rate, PFS, overall survival, and duration of response.

Investigators will also examine the pharmacodynamic activity of the agent with appropriate biomarkers.

Previously, in September 2021, the FDA granted an orphan drug designation to IMX-110 for use as a potential therapeutic in patients with soft tissue sarcoma.2


  1. US Food and Drug Administration approves Immix Biopharma rare pediatric disease designation for IMX-110 as a treatment for life-threatening pediatric cancer in children. News release. Immix Biopharma, Inc.; January 3, 2022. Accessed January 4, 2022. https://bit.ly/3sVKfiI
  2. ImmixBio announces FDA orphan drug designation for IMX-110 for the treatment of soft tissue sarcoma. News release. Immix Biopharma, Inc.; September 30, 2021. Accessed January 4, 2022. https://bit.ly/3qRKLvH
  3. Novel tissue-specific therapeutics (TSTx): targeting oncology & immuno-dysregulated diseases. Immix Biopharma, Inc. website. Accessed January 4, 2022. https://bit.ly/3mXFUYx
  4. IMX-110 in patients with advanced solid tumors. ClinicalTrials.gov. Updated January 21, 2020. Accessed January 4, 2022. https://clinicaltrials.gov/ct2/show/NCT03382340

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