Summer doesn't officially arrive for a few more weeks, but the first week of June packed some real heat. That's especially true for three biotech stocks that rank as our most humongous of the week.

Give me a double
The Motley Fool's David Williamson summed up the great week for Clovis Oncology (NASDAQ:CLVS) perfectly in his headline a few days ago: "1 Biotech + 2 Cancer Drugs = 100% Pop." While that 100% pop drifted down to 96% by the end of the week, Dave hit the nail on the head.

Clovis blew everyone away at the ASCO conference earlier this week, when it announced phase 1 results for cancer drug rucaparib. The drug showed a disease control rate of 89% for ovarian cancer patients across all dose levels. Clovis also said that the safety profile for rucaparib looked good.

The second set of results presented at ASCO centered on experimental drug CO-1686. Phase 1 findings for the drug in treating patients with non-small-cell lung cancer were generally positive but weren't as dazzling as those for rcaparib. Clovis shareholders aren't complaining a bit, though.   

Positive response
Clovis wasn't the only company to bring good news about an ovarian cancer drug to ASCO. TESARO (NASDAQ:TSRO) announced phase 1 results for niraparib. Shares of the biotech jumped 16% for the week.

TESARO reported a Response Evaluation Criteria In Solid Tumors, or RECIST, of 75% for patients with platinum-sensitive high-grade serous ovarian cancer who took a 300 mg dose of niraparib. A 50% RECIST response rate was achieved for patients across all dose levels with platinum sensitive ovarian cancer and germline BRCA mutations.

The biotech also had positive news for the drug in treating other forms of cancer. Two out of four patients with BRCA-positive breast cancer achieved a response. Also, seven out of 10 prostate cancer patients with evaluable circulating tumor cell count levels experienced a reduction of at least 30% in circulating tumor cell count, or CTC, levels. 

Good and better
ACADIA Pharmaceuticals
(NASDAQ:ACAD) benefited from two significant announcements this week. One item was good, but the second was even better. Shares soared 21% on the double-whammy.

First, the good news. ACADIA stated on Monday that its partner Allergan (NYSE:AGN) advanced another new chemical entity from the two companies' collaboration into pre-clinical development. ACADIA's CEO, Dr.  Uli Hacksell, said the molecule has "distinctly different properties from other glaucoma compounds" previously advanced by Allergan. The two companies first partnered on development of new treatments for glaucoma back in 2003.

The better news for ACADIA's stock was announced on Thursday morning. An SEC filing by Baker Bros. Advisors disclosed a 22.6% stake in ACADIA. Baker Bros. Advisors is a hedge fund that holds significant positions in a number of biotechs, including previously mentioned Clovis Oncology. 

Best pick
Which of this week's stars looks to be the best pick now? I'll go with Clovis.

Granted, the stock could see a pullback after the tremendous pop this week. And we're still looking only at phase 1 results for rucaparib. There's a lot that can happen in the days ahead that could derail the company's success.

But this is biotech. Risks are part of the game. If rucaparib experiences positive results in later-stage studies, this humongous week for Clovis could turn into a humongous decade.

Fool contributor Keith Speights and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.