On June 30, 2022 Inhibrx, Inc. (Nasdaq: INBX), a biotechnology company with four clinical programs in development and a robust preclinical pipeline, reported the completion of Phase 1 dose escalation of INBRX-105, a novel targeted 4-1BB agonist, in combination with Keytruda (Press release, Inhibrx, JUN 30, 2022, View Source [SID1234616421]). It also reported the funding of an additional $60 million from its Loan and Security Agreement, as amended (the "Loan Agreement"), with Oxford Finance, LLC ("Oxford"), to bring its cash balance to approximately $176 million as of June 30, 2022.

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"We are very encouraged by the results observed in Part 3 and believe the Part 4 expansion cohorts have been designed to demonstrate the potential of INBRX-105," commented Mark Lappe, Inhibrx’s CEO. "The additional debt provided by Oxford provides non-dilutive financing and, we believe, the time needed to mature our programs ahead of various potential strategic options."

Phase 1 Dose Escalation Results for INBRX-105 in Combination with Keytruda
INBRX-105 is a precisely engineered multi-specific therapeutic candidate based on our single domain antibody ("sdAb") platform designed to agonize 4-1BB selectively in the presence of programmed death ligand 1 ("PD-L1"), a protein typically enriched in the tumor microenvironment and lymphoid tissues.

The study is a first-in-human, multicenter, open-label, non-randomized, Phase 1 trial in patients with locally advanced or metastatic solid tumors. This four-part trial is designed to determine the safety profile and identify the maximum tolerated dose and the recommended Phase 2 dose of INBRX-105 administered in combination with Keytruda, a programmed death receptor-1 checkpoint inhibitor. Part 3, dose escalation in combination with Keytruda, has concluded with a total of 30 patients enrolled. Patients were not pre-screened for PD-L1 expression. INBRX-105 in combination with Keytruda was reasonably well-tolerated and we observed durable responses in checkpoint-naïve and relapsed refractory patients. These results informed what we believe to be the optimal dose level for INBRX-105 in combination with Keytruda in Part 4. Additionally, single agent responses have been observed at this same dose level in both checkpoint-naïve and relapsed/refractory patients.

Part 4, dose expansion cohorts of INBRX-105 in combination with Keytruda, initiated enrollment in May 2022. This will include a total of approximately 90 patients in five separate cohorts and we expect to announce initial data from these cohorts in the first half of 2023.

Additional $60 Million in Debt from Oxford
On June 29, 2022, Inhibrx drew two additional term loans from its Loan Agreement with Oxford for an aggregate principal amount of $60.0 million. The two additional term loans were based on the completion of the following:

$30 million upon the receipt of positive topline data from the Phase 1 clinical trial of INBRX-101, our AAT-Fc fusion protein for the treatment of Alpha-1 antitrypsin deficiency, which we released in May 2022; and
$30 million upon initiation of Part 4 of the Phase 1 clinical trial of INBRX-105, our PD-L1x4-1BB tetravalent conditional agonist.
Inhibrx has one additional $30 million tranche available under the Loan Agreement, which will be available to fund upon the initiation of a potential registration-enabling clinical trial of INBRX-101. To date, the aggregate balance of Inhibrx’s outstanding term loans, which mature in January 2027, is $170.0 million. The repayment schedule provides for interest-only payments until March 2025 with a potential 12-month extension.