Item 7.01. Regulation FD.

On January 19, 2023, Sonnet BioTherapeutics Holdings, Inc. (the “Company”)
issued a press release announcing that pharmacokinetic (“PK”) profile simulation
of SON-1010 dosing has been completed in its randomized, placebo-controlled
Phase 1 clinical trial in healthy volunteers. A copy of the press release is
attached hereto as Exhibit 99.1.

The information in this Current Report on Form 8-K under Item 7.01, including
the information contained in Exhibit 99.1, is being furnished to the Securities
and Exchange Commission, and shall not be deemed to be “filed” for the purposes
of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange
Act”), or otherwise subject to the liabilities of that section, and shall not be
deemed to be incorporated by reference into any filing under the Securities Act
of 1933, as amended, or the Exchange Act, except as shall be expressly set forth
by a specific reference in such filing.

Item 8.01. Other Events.

On January 19, 2023, the Company issued a press release announcing that PK
profile simulation of SON-1010 dosing has been completed in its randomized,
placebo-controlled Phase 1 clinical trial in healthy volunteers. Historically,
the therapeutic application of cytokines has been limited by relatively short
half-lives and off-target toxicities that are typically associated with peak
plasma levels. SON-1010 is a proprietary version of recombinant human
interleukin-12 (“rhIL-12”), configured using the Company’s Fully Human Albumin
Binding (“FHAB”) technology, which has been shown to extend PK and to reduce
peak drug levels for improving pharmacodynamic (“PD”) toxicity. The FHAB
technology was designed to promote targeting to the tumor microenvironment
(“TME”), particularly when levels of secreted protein acidic and rich in
cysteine are elevated in the TME. Study SB102 (“SB102”) is a single-ascending
dose trial in healthy volunteers (NCT05408572) that was initiated in July, 2022
to address the safety, PK, and PD of SON-1010 in subjects without interference
from prior chemotherapy. The Safety Review Committee has found no significant
safety concerns to date and has approved advancing to each higher dose level.

Typical dose-related increases were seen with SON-1010 using a validated
electrochemi¬luminescence assay after subcutaneous administration. Drug levels
peaked at about 11 hours with a geometric mean maximum concentration (“Cmax”) of
29, 68, and 125 pg/mL for the 50, 100, and 150 ng/kg dose groups, respectively.
The mean elimination half-life (“T½”) after a 150 ng/kg dose of SON-1010 was 112
hours, compared to 12 hours for rhIL-12.

Observed increases in interferon gamma (“IFN?”) were most pronounced and were
dose-related, controlled, and prolonged. SON-1010 induced IFN? in all
active-drug subjects, which peaked at 24 to 48 hours then returned to baseline
after 2 weeks. The IFN? geomean Cmax was 398, 384, and 666 pg/mL after 50, 100,
or 150 ng/kg of SON-1010, respectively, while the AUC over 48 hours was 6050,
10200, and 14600 h*pg/mL. Linear regression was used to predict the IFN? Cmax at
higher doses, which remain well within the range of safety. Low amounts of IL-10
were induced in a dose-dependent manner, which could also be due to the increase
in IFN?. There were small transient increases in IL-6, IL-8, and TNF? after
dosing but no consistent pattern was seen with IL-1?, IL-2, or IL-4 and there
was no evidence of cytokine release syndrome. Safety was consistent with what
has been reported previously; adverse events have generally been mild/moderate,
transient in nature, and have all been tolerable.

SB102 is designed to robustly evaluate the safety, PK and PD of single ascending
doses of SON-1010, using larger groups of healthy volunteers, and is being
conducted at a single site in Australia. The study is done in a blinded fashion,
comparing a single dose of SON-1010 to placebo utilizing up to five cohorts.
Both PK and PD will be closely followed during dose escalation in this
double-blind, placebo-controlled study, along with an assessment of the cellular
immune responses at each dose using sophisticated fluorescence activated cell
sorting analysis. The primary endpoint explores the safety and tolerability of
SON-1010, with key secondary endpoints intended to measure PK, PD, and

Item 9.01. Financial Statements and Exhibits.

(d) The following exhibit is furnished with this report:

Exhibit No.   Description
99.1            Press Release issued by Sonnet BioTherapeutics Holdings, Inc.,
              dated January 19, 2023.
104           Cover Page Interactive Data File (embedded within the Inline XBRL

© Edgar Online, source Glimpses

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