Word to mean "then-current" [duplicate]

Solution 1:

prevailing: existing or most common at a particular time

"The doctor's report of June 2008 set forth the patient's prevailing complaints."

The OP's phrasing of 'then-current':
then in this sense does not agree with current – then refers to a time in the past and current to the present.

The adjective for a particular time in the past corresponding to current is prevailing (at that time).

Use cases:

• Practically the entire dried apricot crop was sold at the prevailing market price …
• On the parent books, the declared dividend was valued at the prevailing USD/EUR exchange rate and recognised as dividend income and a dividend receivable.
• Less than two per cent of the total consumption of newsprint consumed in the United States during the period in question was sold at gray market prices, and the remaining 98 plus per cent was sold at the prevailing base prices.
• When both the status of the physical system and the signal timing are ideal, the traffic signal system can achieve its ideal performance which can generally represent the best performance the system can achieve under a specific prevailing condition.
• In monitoring physical adjustment it is important to check out the symptoms prevailing at the time of assessment, and whether they have changed over time, as a result of treatment.
• In nearly every case thus reported the symptoms prevailing at the time developed later into diphtheria.
• At the time of issue, the bonds are generally priced at the prevailing market price.
• The writer has tested this new tail-piece many times and has never seen any good results unless the remedy was indicated by the symptoms prevailing at the time.

Solution 2:

I think you should say something like concurrent symptoms or complaints. In the current context it would be an almost literal translation of 'then-current'.

adj. taking place at the same time.

Here is a good example of the use of concurrent in this context. And here's another good one.