Study of RP1 Monotherapy and RP1 in Combination With Nivolumab

RP1 is a genetically modified herpes simplex type 1 virus that is designed to directly
destroy tumors and to generate an anti-tumor immune response. This is a Phase 1/2, open
label, multicenter, dose escalation and expansion, first-in-human (FIH) clinical study to
evaluate the safety and tolerability, biodistribution, shedding, and preliminary efficacy of
RP1 alone and in combination with nivolumab in adult subjects with advanced and/or refractory
solid tumors. The study will include a dose escalation phase for single agent RP1, an
expansion phase with a combination of RP1 and nivolumab and a Phase 2 portion in specified
tumor types for the combination therapy.

Inclusion Criteria:

- Must be willing and able to participate and comply with all trial requirements and
able to provide signed and dated informed consent prior to initiation of any trial
procedures

- Male or Female ≥ 18 years of age

- Have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1.

- Have at least one injectable tumor

- Have laboratory values (obtained ≤ 28 days prior to first infusion day) in accordance
with the study protocol

- Women of child-bearing potential (WOCBP) must have a negative urine pregnancy test at
screening and a negative urine pregnancy test prior to administration of each dose of
RP1 or nivolumab

- WOCBP must agree to use adequate birth control throughout their participation and for
3 months after RP1 alone and 5 months after nivolumab last study treatment

- Males with partners of child-bearing potential must agree to use adequate birth
control throughout their participation and for 3 months for RP1 alone and 7 months
after nivolumab last study treatment

For Subjects in the Combination Treatment

- Baseline ECG that does not show abnormalities according to the protocol

- Baseline oxygen saturation levels that do not show abnormalities according to the
protocol

- Have provided a former tumor pathology specimen or be willing to supply a new tumor
sample from a biopsy

For Subjects in Phase 2 only

- Have a predicted life expectancy of ≥ 3 months

- Evaluable or measurable disease, according to Response Evaluation Criteria in Solid
Tumors (RECIST) v1.1 criteria,

- Subjects with melanoma: has Stage IIIb to IV (skin, eye or mucosal) for whom anti PD-1
therapy is indicated or who have previously received an anti-PD-1 therapy, or have
refused, become intolerant to or have no further therapy options available

- Subjects with MSI-H tumors: has diagnosis of MSI-H tumor (according to protocol
definition) for whom anti PD-1 therapy is indicated, or have refused, become
intolerant to or have no further therapy options available

- Subject with dMMR tumors: has diagnosis of dMMR tumor (according to protocol
definition) for whom anti PD-1 therapy is indicated, or have refused, become
intolerant to or have no further therapy options available

- Subject with NMSC: has diagnosis of locally advanced or metastatic NMSC that are not
considered treatable by surgery including basal cell carcinoma, cutaneous squamous
cell carcinoma, basosquamous carcinoma, Merkel cell carcinoma and other non-melanoma
skin cancers (per protocol) for whom anti PD-1 therapy is indicated, or have refused,
become intolerant to or have no further therapy options available Subjects with
bladder cancer: diagnosis of locally advanced or metastatic bladder cancer for whom
anti PD-1 therapy is indicated, or have refused, become intolerant to or have no
further therapy options available

Exclusion Criteria:

- Prior treatment with an oncolytic therapy

- History of viral infections according to the protocol

- Systemic infection requiring IV antibiotics within 14 days prior to dosing

- Prior complications with herpes infections

- Chronic use of anti-virals

- Systemic therapies for cancer within 4 weeks of first dose (some others may be
accepted with shorter time periods)

- Conditions that require certain doses of steroids (some doses and types will be
permitted)

- Known active brain metastases - previously treated brain metastases may be permitted

- Prior certain other diagnosis of cancer

- Is participating in another clinical study or has participated in the past 4 weeks
prior to the first dose

Combination Phase Subjects

- Certain autoimmune diseases, some types will be permitted

- Allergy or sensitivity to study drug components

- History of interstitial lung disease

- History of non-infectious pnuemonitis

- Other serious or uncontrolled medical disorders