April's biggest gainer in the healthcare sector was Akorn (AKRX) - Get Report which confirmed on April 7 that it is in deal discussions with Fresenius Kabi, a subsidiary of Fresenius SE. Then on April 24, the firms made it official: Akorn agreed to sell to Fresenius for $4.75 billion.

Akorn shares rose from $23.33 on April 4 to 33.39 and a 37% gain through mid-day trading Friday.

Akorn's rise led the list of biggest risers among healthcare stocks in the S&P 1500, according to FactSet.

Shares of MiMedx (MDXG) began rising steadily on April 13 after the company reported that first-quarter revenue would exceed the upper end of MiMedx's guidance. The company said it would record first-quarter revenue of $72.6 million, a $19.1 million or 36% increase over 2016 first quarter revenue of $53.5 million.

MiMedx makes regenerative biomaterial products and bioimplants from human amniotic membrane and other birth tissues and human skin and bone.

COO Bill Taylor noted at the time the strong first-quarter performance "is a firm indicator to us that we are gaining market share quarter-over-quarter."

He predicted the momentum will continue and demand from physicians, patients and payors for the company's dehydrated Human Amnion/Chorion Membrane products will continue to increase throughout 2017 and beyond.

During 2016 MiMedx launched three products, EpiCord, a new dehydrated human umbilical cord allograft; AmnioFill, the company's first commercial launch in its placental collagen matrix product family; and OrthoFlo Lyophilized, an extension of the company's amniotic fluid product family.

MiMedx formally reported earnings Friday that alone pushed the shares up 11.32% for the day to $12.69, a $1.29 rise. For the month MiMedx was up 33%.

Cytokinetics (CYTK) - Get Report climbed 32.3% to $17 during the month, largely after an April 17 announcement that its shares would be added to the S&P Small Cap 600. Cytokinetics replaced Cardinal Financial (CFNL)  , which is being acquired by United Bankshares (UBSI) - Get Report .

Cytokinetics started the month at $12.85 and dipped as low as $11.20 on April 5. 

On April 25 H.C. Wainwright analyst Joseph Pantginis issued a buy recommendation on Cytokinetics, with a price target of $25.

Wainwright said he was optimistic about prospects for Cytokinetics' lead drug, CK-107, a treatment for spinal muscular atrophy (SMA), a rare and often fatal genetic disease affecting muscle strength and movement. 

He noted the strong early uptake for Biogen's (BIIB) - Get Report Spinraza, approved by the Food and Drug Administration in December, the first drug approved to treat children and adults with SMA.

Wainwright said that CK-107's muscle activation mechanism is likely to be complementary to Spinraza's and other SMA drugs in the works. "As physicians are finally being provided with treatment options for SMA, we believe that the market will be primed for CK-107, if approved," he wrote.

Shareholders of C.R. Bard (BCR)  gained a windfall when Becton, Dickinson (BDX) - Get Report announced April 23, that it will acquire its medical technology peer for $24 billion, the largest-ever deal for the 120-year-old buyer.

The purchase price represents a 25.3% premium over Bard's closing price of $253.07 the previous trading day. For the month, C.R. Bard shares were up 23%, according to FactSet.

Shares ofInvacare (IVC) - Get Reportjumped 23.5% to $14.70 in April. The Elyria, Ohio-based medical equipment maker and distributor said April 27 it has completed the final two milestones needed to initiate the U.S. Food and Drug Administration's re-inspection of its corporate and Taylor Street facilities. The facilities have been impacted by a consent decree with FDA since December 2012.

Spectrum Pharmaceuticals (SPPI) - Get Report has risen 21% after presenting positive preclinical data on Rolontix (eflapegrastim) at the American Association for Cancer Research annual meeting April 4. Rolontix is being developed to fight infection in patients undergoing chemotherapy.

It is meant to be a competitor to pegfilgrastim, which is sold around the world by Amgen (AMGN) - Get Report , Roche (ROG) - Get Report and other drug companies.

"We are excited to see positive data continuing to develop in our highest priority program," Spectrum chairman and CEO Rajesh Shrotriya, said at the time. "The data shows that in this preclinical study, eflapegrastim was found to be more potent in shortening the duration of severe neutropenia. Eflapegrastim was more potent than pegfilgrastim at G-CSF equivalent doses in neutropenic animal models."

Shrotriya said Spectrum is enrolling patients for an upcoming trial and expects to file a biologics license application with the FDA next year.

Editors' pick: Originally published April 28.