- Men and women aged 18 or older.
- Willingness to provide written informed consent for the study.
- Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1.
- Locally advanced or metastatic disease; locally advanced disease must not be amenable
to resection with curative intent.
- Subjects with advanced or metastatic head and neck squamous cell carcinoma, non-small
cell lung cancer, and breast cancer who are Siglec-15 positive.
- Subjects who have disease progression after treatment with available therapies that
are known to confer clinical benefit, or who are intolerant to treatment, or who
refuse standard treatment. Note: There is no limit to the number of prior treatment
- Presence of measurable disease based on RECIST v1.1. Tumor lesions situated in a
previously irradiated area, or in an area subjected to other locoregional therapy, are
not considered measurable unless there has been demonstrated progression in the
- Willing to undergo pretreatment and on-treatment tumor biopsies (core or excisional).
- Female subjects of childbearing potential (defined as women who have not undergone
surgical sterilization with a hysterectomy and/or bilateral oophorectomy and are not
postmenopausal, defined as ≥ 12 months of amenorrhea) must have a negative serum
pregnancy test at screening. All female and male subjects of childbearing potential
must agree to take appropriate precautions to avoid pregnancy or fathering children
(with at least 99% certainty) from screening through 60 days after the last dose of
- Inability to comprehend or unwilling to sign the Informed Consent Form.
- Screening laboratory values of:
1. Absolute neutrophil count < 1.5 × 10^9/L
2. Platelets < 100 × 10^9/L
3. Hemoglobin < 9 g/dL or < 5.6 mmol/L
4. Serum creatinine > 1.5 × institutional upper limit of normal (ULN)
5. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≥ 2.5 × ULN
6. Total bilirubin ≥ 1.5 × ULN.
7. International normalized ratio (INR) or prothrombin time (PT) > 1.5 × ULN
8. Activated partial thromboplastin time (aPTT) > 1.5 × ULN
- Transfusion of blood products (including platelets or red blood cells) or
administration of colony-stimulating factors (including granulocyte colony-stimulating
factor, granulocyte macrophage colony-stimulating factor, or recombinant
erythropoietin) within 7 days before the first administration of study drug.
- Receipt of anticancer medications or investigational drugs within the following
intervals before the first administration of study drug:
1. ≤ 14 days for chemotherapy, targeted small molecule therapy, or radiation
therapy. Subjects must also not require chronic use of corticosteroids and must
not have had radiation pneumonitis because of a treatment. A 1-week washout is
permitted for palliative radiation to non-central nervous system (CNS) disease
with medical monitor approval. Note: Bisphosphonates and denosumab are permitted
2. ≤ 28 days for prior immunotherapy or persistence of active cellular therapy
(e.g., chimeric antigen receptor T cell therapy; other cellular therapies must be
discussed with the medical monitor to determine eligibility).
3. ≤ 28 days for a prior monoclonal antibody used for anticancer therapy except for
4. ≤ 7 days for immune-suppressive-based treatment for any reason. Note: Use of
inhaled or topical steroids or corticosteroid use for radiographic procedures is
permitted. Note: The use of physiologic corticosteroid replacement therapy may be
approved after consultation with the medical monitor.
5. ≤ 28 days or 5 half-lives (whichever is longer) before the first dose for all
other investigational study drugs or devices. For investigational agents with
long half-lives (e.g., > 5 days), enrollment before the fifth half-life requires
medical monitor approval.
6. ≤ 14 days for COVID-19 vaccine.
- Has not recovered to ≤ Grade 1 from toxic effects of prior therapy (including prior
immunotherapy) and/or complications from prior surgical intervention before starting
therapy. Note: Subjects with stable chronic conditions (≤ Grade 2) not expected to
resolve (such as neuropathy and alopecia) are exceptions and may enroll. Note:
Subjects with a history of any grade immune-related ocular AE (e.g., episcleritis,
scleritis, uveitis) will be excluded.
- Receipt of a live vaccine within 30 days of planned start of study therapy. Note:
Examples of live vaccines include, but are not limited to, the following: measles,
mumps, rubella, chicken pox/zoster, yellow fever, rabies, Bacillus Calmette-Guérin,
and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed
virus vaccines and are allowed; however, intranasal influenza vaccines (e.g.,
FluMist®) are live attenuated vaccines and are not allowed.
- Active autoimmune disease that required systemic treatment in the past (i.e., with use
of disease-modifying agents, corticosteroids, or immunosuppressive drugs). Note:
Subjects with hyperthyroidism or hypothyroidism, who have not required systemic
treatment for an autoimmune disease for at least 2 years and are stable on thyroid
hormone replacement are allowed to participate in the study. Note: Replacement and
symptomatic therapies (e.g., levothyroxine, insulin, or physiologic corticosteroid
replacement therapy for adrenal or pituitary insufficiency, etc.) are not considered a
form of systemic immune suppressive therapy and are allowed.
- Known active CNS metastases and/or carcinomatous meningitis. Note: Subjects with
previously treated brain metastases may participate provided they are stable (without
evidence of progression by imaging for at least 28 days before the first dose of study
drug and any neurologic symptoms have returned to baseline), have no evidence of new
or enlarging brain metastases or CNS edema, and have not required steroids for at
least 7 days before the first dose of study drug.
- Known additional malignancy that is progressing or requires active treatment, or
history of other malignancy within 2 years of study entry after treatment with
curative intent. Note: Cured basal cell or squamous cell carcinoma of the skin,
superficial bladder cancer, prostate intraepithelial neoplasm, carcinoma in situ of
the cervix, or other noninvasive or indolent malignancy, or cancers from which the
subject has been disease-free for > 1 year are not considered exclusionary.
- Evidence of active, noninfectious pneumonitis or history of interstitial lung disease.
- History or presence of an abnormal electrocardiogram (ECG) that, in the investigator's
opinion, is clinically meaningful.
- Uncontrolled systemic fungal, bacterial, viral, or other infection despite appropriate
- Evidence of hepatitis B virus (HBV) or hepatitis C virus (HCV), unless the hepatitis
is considered to be cured.
- Known history of HIV (HIV 1 or HIV 2 antibodies).
- Known allergy or reaction to any component of study drug or formulation components.
- Is pregnant or breastfeeding or expecting to conceive or father children within the
projected duration of the study, starting with the screening visit through 60 days
after the last dose of study treatment.