It seems like it has pretty good support at $4

It seems like it has pretty good support at $4 and pretty substantial resistance at $5.50.  Forming a pennant. 

If there is an "announcement" on May 23rd, it could really move the stock quite a bit in either direction.  I always get nervous about the potential moves of these biotech firms.

It is a little risky holding uncovered calls in this situation.  Theoretically, you have unlimited loss potential with only a bit a premium received to show for the risk.

Even the covered call, in my opinion, is not the best strategy.  It only partially protects you on the downside, but can substantially limit your upside potential.

I do agree in selling the volatility in this security.  IV/HV is near 3 right now.  That is crazy volatility ripe to be sold.

However, it would be better to play a butterfly or straddle.  If you opened a butterfly at June 4-5-6 (1 long 4 Call, 2 short 5 Call, 1 long 6 Call), then maximum gain for per 1-2-1 contract ratio would be ~$80 per lot and maximum loss would be ~$20. Breakevens at expiration would be $4.20 and $5.80.  To top it off, the overall position would be a net negative VEGA position.  So, if volatility decreased then the overall position would further benefit through increased gain and wider breakevens.

Since the IV avg is near 175 before this "announcement" and HV is near 50, it can be anticipated that volatility will drop after the announcement.  Playing this IV crush in your favor would be a good strategy.

Selling a Jun 5 straddle is also a great Net negative Vega strategy, particularly with such ridiculous IV at this point.  If you sold a 1 contract Jun 5 straddle you could capture $197.50 at midpoint fill and only take about $92.20 margin due to the low value of the security.  Typically, brokerages require 20% of the cost of the underlying as a margin requirement.  In this situation, Breakevens would be $3.02 and $6.98.  Because it is a net negative Vega strategy, with the anticipated IV drop, you could easily cash out either of these positions well before June Expiration and capture most of the profit early.

The positions you put yourself in have very limited upside and greater risk of loss relative to eithe of the above positions.  You are not really taking full advantage of the increased volatility as well.

There is going to be an up and coming Volatility Crush.  You want to be on the right side of it and maximize probability of profit while carrying the least amount of downside risk.