Does "phase 1/2 clinical trial' mean "phase 1 and phase 2 clinical trials"?

1)Does "phase 1/2 clinical trial' mean "phase 1 and phase 2 clinical trials"?
2) Does " viral (AAV) vector encoding REP1" mean "viral vector that encodes REP1"?
3) What is "genome particles"?

Context:

Retinal gene therapy in patients with choroideremia: initial findings from a phase 1/2 clinical trial

Background
Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1). We assessed the effects of retinal gene therapy with an adeno-associated viral (AAV) vector encoding REP1 (AAV.REP1) in patients with this disease.
Methods
In a multicentre clinical trial, six male patients (aged 35—63 years) with choroideremia were administered AAV.REP1 (0·6—1·0×1010 genome particles, subfoveal injection). Visual function tests included best corrected visual acuity, microperimetry, and retinal sensitivity tests for comparison of baseline values with 6 months after surgery. This study is registered with ClinicalTrials.gov, number NCT01461213.
Findings