UPDATE 2-Novartis joins CureVac's vaccine contractor line-up

* Trial read-out expected early in second quarter

* Other partners include Bayer, GSK, Fareva, Rentschler

* Novartis site to come online in summer of 2021

* Novartis to make up to 50 mln doses this year (Adds update on timing of trial read-out, production plan)

By Ludwig Burger

FRANKFURT, March 4 (Reuters) - German biotech firm CureVac has enlisted Swiss pharmaceutical giant Novartis to help produce its experimental COVID-19 vaccine, boosting a network of contract manufacturers ahead of results from a pivotal trial.

Novartis plans to manufacture the mRNA molecules the two-shot vaccine is based on as well as "bulk drug product" for up to 50 million doses by the end of 2021 and up to a further 200 million doses in 2022, the two companies said on Thursday.

Delivery from the manufacturing site in Kundl, Austria, is expected to start in summer 2021, they said.

CureVac expects initial results from its late-stage trial early in the second quarter rather than this month because the biotech company plans to publish read-outs for specific variants, a spokesman said.

"We need a certain number of cases for each virus variant to arrive at statistically significant results," he said.

Variants that are on the rise in South Africa and Brazil in particular have raised concerns about a potential loss in vaccine efficacy.

Novartis joins a list of CureVac partners for manufacturing and filling vials that include Bayer, family-owned Fareva of France, Wacker and Rentschler Biopharma SE.

Britain's GlaxoSmithKline, which is working with CureVac on next-generation vaccines that target several coronavirus variants with one shot, will also help with production this year.

CureVac, which began late-stage testing of the vaccine in December, reiterated that it aims to produce up to 300 million doses in 2021 and 600 million to 1 billion doses in 2022. (Reporting by Ludwig Burger; Editing by Thomas Escritt, Emma Thomasson and David Clarke)