I wrote a quick script based on the documentation from PDF::API2 and it works fine without using an intermediate file:

#!/usr/bin/env perl
use strict;
use warnings;
use PDF::API2;

# Create a blank PDF file
my $pdf = PDF::API2->new();

# Add a blank page
my $page = $pdf->page();

# Set the page size
$page->mediabox('Letter');

# Add a built-in font to the PDF
my $font = $pdf->corefont('Helvetica-Bold');

# Add some text to the page
my $text = $page->text();
$text->font($font, 20);
$text->translate(200, 700);
$text->text('Hello World!');

# Save the PDF
$pdf->saveas('new.pdf');
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