FDA Grants Orphan Drug Designation for JBI-802 in SCLC and AML

JBI-802, which is being evaluated in a phase 1/2 trial, received an orphan drug designation from the FDA for the treatment of patients with small cell lung cancer and acute myeloid leukemia.

The FDA has granted an orphan drug designation to JBI-802 for the treatment of patients with small cell lung cancer (SCLC) and acute myeloid leukemia (AML), according to Jubilant Therapeutics Inc.1

JBI-802 is a dual epigenetic modulator. The agent is engineered in a single pharmacophore and works to achieve optimal inhibition of the transcriptional regulator CoREST, which regulates the development of cellular lineages responsible for neuroendocrine tumors, including SCLC, and hematopoietic tumors like AML.

"JBI-802 is the lead product candidate from our TIBEO [Therapeutic Index and Brain Exposure Optimization] Discovery Engine. It is our unique approach of structure-based drug design to generate novel pharmacophores with improved target product profile compared to existing agents. The orphan drug designations were supported by several relevant preclinical models. In SCLC, JBI-802 showed unique activity not just in normal neuroendocrine models but also in the 'variant' models driven by MYC amplification. This data also supports the ongoing [phase 1/2] clinical trial in neuroendocrine tumor patients. In AML the activity was uniquely seen in models of erythroleukemia, a subset of leukemia, with a unique erythroid phenotype and a very high unmet need based on its aggressive nature and limited therapy,” said Syed Kazmi, chief executive officer of Jubilant Therapeutics Inc, in the press release.

In preclinical research examining JBI-802, the agent demonstrated its synergistic anti-tumor activity, which showed to be superior when compared with inhibitors of either target alone. JBI-802 also demonstrated a favorable safety profile with no significant safety concerns or accumulation.

JBI-802 has a unique profile which previously elicited synergistic antitumor activity. Treatment with JBI-802 is expected to overcome tolerability limitations of first-generation, single target epigenetic modulators.

To further examine JBI-802, investigators are clinically evaluating the agent in multiple neuroendocrine tumors, including SCLC. The goal of this research is to expand into hematological cancers, such as AML, essential thrombocythemia, and other myeloproliferative cancers.

This phase 1/2 multicenter, first-in-human, open-label, 2-part, dose-escalation and expansion study (NCT05268666), will determine the safety, tolerability, maximum tolerated dose (MTD), pharmacologically active dose, preliminary efficacy, and predictive and pharmacodynamic biomarkers in up to 126 participants with advanced solid tumors.2

In the expansion cohorts of the trial, patients with SCLC, neuroendocrine prostate cancer (NEPC), and other neuroendocrine-derived cancers will be treated at the recommended phase 2 dose (RP2D), starting at 10 mg orally once daily, 4 days on and 3 days off cycle. The goal for these cohorts is to obtain additional safety and efficacy data.

The primary end point of the trial is to determine the MTD. Secondary end points include evaluating safety, including the incidence of adverse events, pharmacokinetics, investigator-assessed overall response rate, duration of response, progression-free survival, overall survival, and more.

Patients are eligible for enrollment in the study if aged 18 years and older with at least 1 measurable lesion on CT scan or MRI per RECIST 1.1, and an ECOG performance status of ≤2. In part 1 of the trial, patients must have a histologically confirmed diagnosis of locally advanced or metastatic solid tumors and have no available effective therapeutic options. This portion of the trial excludes patients with microsatellite stable colorectal cancer and hepatocellular carcinoma.

In part 2, patients must have a histologic diagnosis of advanced SCLC not amenable to curative therapy, have received ≤2 prior regimens, including a checkpoint inhibitor and a platinum-based chemotherapy, or have novo or treatment-emergent NEPC.

The trial is ongoing in Colorado, Ohio, Tennessee, and Virginia, and has an estimated study completion date of August 2025.

“This designation and emerging clinical data from the ongoing fist-in-human JBI-802 study will now underpin expansion of our clinical activities in thrombocythemia, leukemia and other erythroid tumors like MPN," added Kazmi in the press release.

REFERENCES:
Jubilant Therapeutics Inc. receives orphan drug designation for JBI-802 for acute myeloid leukemia (AML) and small cell lung cancer (SCLC). News release. Jubilant Therapeutics Inc. January 5, 2023. Accessed January 12, 2023. https://prn.to/3iBFV5t
A study of orally administered JBI-802, an LSD1/HDAC6 inhibitor, in patients with advanced solid tumors. ClinicalTrials.gov. Updated August 22, 2022. Accessed January 12, 2023. https://clinicaltrials.gov/ct2/show/NCT05268666?term=JBI-802&draw=2&rank=1