Doesn't look good, does it?

1. Debenture kicked down the road again? - not likely, would have heard that by now, plus the opened Hepa BoD seat suggests otherwise

I agree, although there is a chance that Hepa and RVX are in late stage negotiations to kick the can down the road depending on how other options are looking to pay Hepa out. For instance, if Zenith is close to a deal, but not quite there, Hepa might elect to defer repayment for some amount of time to get the deal closed. Since the clearest picture will be closer to the deadline, if a deferral is granted then it won't be until on or close to the deadline.

2. RVX pays the debenture? - possible, thru Zenith, Don, Insiders, etc. Qater? Plus the vacated BoD seat could be an indication. Holding news till the last minute for PPS considerations for financier(s)?

IMO this is unlikely since money has been scarce and who would pay $6MM without any reasonable assurance that future trials are going to be completed? They'd just take the place of Hepa now, and Hepa wants to get repaid for a reason (no prospects).

3. Hepa conversion? - possible also, maybe the likeliest probability. No cash or ability to raise capital. Holding news for conversion PPS optimization? Might also explain the BoD vacancy, but it seems to me they would keep theur BoD seat thru all of that?

Hepa wouldn't leave the board if they were going to convert, IMO. So I don't think this will happen.

4. Loggerheads? - RVX can't pay debenture, but won't cooperate, unaffordable lawsuit coming over IP control and curing current issue? Delay tactic?

This makes sense and is the simplest explanation. Hepa wants to get their money back and RVX can't pay.

I could see either #4 and #1 being reality come Monday. If there's no news on or before Monday, I guess that means RVX is then in default of the Hepa loan.